STATEMENT OF THE CLASS SUBJECT MATTER:
A. Systems and processes for transmission or reception of radio wave energy for obtaining or utilizing information (using radio wave transmitters or receivers), as to an object, or as to the directional characteristics of the radio wave energy, per se.
B. This class includes radar systems wherein radio wave energy from a transmitter is reflected or otherwise returned from an object to a receiver which may be at the same location as the transmitter.
C. This class includes subsystems, components, and related processes which are limited to use in connection with the above and not provided for elsewhere.
D. This class is limited to electromagnetic radio frequency waves in the radiation field. Radiation waves produces by lasing (coherent addition) action and induction field electromagnetic waves are excluded from this class, even though they may operate at radio frequencies. See "radio wave" definition above for other type exclusions.

REFERENCES TO OTHER CLASSES

SEE OR SEARCH CLASS:
73, Measuring and Testing, 570 for miscellaneous apparatus for testing devices by means of vibratory forces (e.g., certain types of compressional waves), see indented subclasses 584+ where sound waves are used. Class 73 provides for measuring and testing methods and apparatus which involve a radiant energy test and a nonelectrical test. Class 73 is the generic class for measuring and testing methods and apparatus, Search notes to the class definition of Class 73 should be consulted for other classes which provide for measuring and testing processes and apparatus.
89, Ordnance, 1.1 and 41 for apparatus designed to control or move a gun for aiming it towards a target, including such apparatus where radiant energy is utilized and subclasses 1.51+ for radiant energy actuated or controlled devices for
releasing bombs, flares, etc., from aircraft.
102, Ammunition and Explosives, subclass 384 for drop bombs with direction controlling means, including those controlled by radiant energy; subclasses 416+ and the subclasses specified in the notes thereto for explosive mines adapted to be fixed automatically, the firing device of the mine being actuated by electrical, magnetic, wave or radiant energy and the igniting, per se, for such mines; and subclass 214 for fuses, primers and igniting devices for explosives which involve the utilization of electrical, magnetic, wave or radiant energy in their operation.
136, Batteries: Thermoelectric and Photoelectric, 200 for thermoelectric generators, particularly subclasses 213+ for radiation (e.g., infrared) pyrometers.
137, Fluid Handling, appropriate subclasses for fluid flow control systems including radiant energy systems for valve actuation.
178, Telegraphy, appropriate subclasses with respect to inductive coupling where the sole disclosure is of a radiant energy telegraph system, but the claimed subject matter is not limited to radiant energy transmission of the signals. See especially subclass 18.07 and 19.03 for handwriting and drawing systems with inductive coupling, subclass 43 for space induction systems, subclasses 66.1+ for miscellaneous systems using alternating current (including high frequency current) to transmit the signal. Note that many of the patents in subclasses 66.1+ of Class 178 are analogous to the patents of Class 375, subclasses 259+ for miscellaneous telegraph apparatus useful in either radio or wire telegraphy, for example, subclasses 371+ for receivers and subclasses 348+ for keys.
181, Acoustics, is the generic class for inventions in sound wave radiation, transmission or reception and instruments specific thereto.
191, Electricity: Transmission to Vehicles, subclass 10 for systems for transferring energy from a roadway or other place to a movable vehicle by means of electromagnetic induction.
244, Aeronautics, subclass 3.1 for control means for missiles and subclass 77 for systems for automatically controlling aircraft by means of electrical apparatus and radiant energy controlled steering and for a statement as to the lines between the classes.
250, Radiant Energy, subclasses 200-239 for light sensitive systems and subclass 336.1 for methods and apparatus utilizing invisible ray energy for measuring and detecting purposes; subclass 492.1 for methods and apparatus utilizing invisible ray energy such as X-rays, ultraviolet infrared rays. Class 250 is the generic class of radiant energy. It and other classes specified in the search class notes to it
should be searched for the patents relating to radiant energy apparatus, processes and devices, especially for processes and apparatus for subjecting materials to radiant energy.
318, Electricity: Motive Power Systems, subclass 16 for electric motor systems where the motor is controlled or supplied by space transmitted electromagnetic or electrostatic energy (including radio energy), subclass 460 for electric motor systems controlled by sound or supersonic vibrations, subclass 480 for electric motor systems controlled by radiant energy (e.g., light).
324, Electricity: Measuring and Testing, is the generic class for methods and apparatus for testing to determine electrical properties by electrical means; 323 and 344+ provide for ore detection determination by electrical means, including the use of radio waves, except such methods and apparatus which involve the use of reflected or otherwise returned radio waves, the excepted matter being in this class (342). Class 324 provides for electrical testing methods and apparatus which include a test by means of radio waves and another electrical test.
333, Wave Transmission Lines and Networks, appropriate subclasses for wave transmission lines or networks which may be used for communication purposes wherein the wave energy is guided or constrained by a wave propagating medium of appreciable electrical length with respect to the wave length of the propagated energy. For example, 1 provides for plural channel systems and subclasses 236+ provides for single channel long lines having distributed electrical parameters, such as parallel conductors, wave guides and shielded lines. This class also contains systems and networks useful in communication with radiant energy. See particularly subclasses 109+ for directional couplers, subclass 117 for hybrid type networks, subclass 13 for resonator type breakdown discharge systems, e.g., T-R or R-T systems, subclass 23 for dissipating terminations for long lines, subclasses 24+ for coupling networks including filters, equalizers, dealt networks and impedance matching networks and subclass 81 for attenuators.
334, Tuners, appropriate subclasses for tuner networks adapted for use in radiant energy systems.
343, Communications: Radio Wave Antennas, appropriate subclass for structural apparatus for the transmission or reception of radio waves.
345, Computer Graphics Processing, Operator Interface Processing, and Selective Visual Display Systems, 418 for computer s:graphic processing and subclasses 326+ for computer operator interface processing.
348, Television, appropriate subclasses for television systems whether the signals are transmitted by radiant energy or otherwise.
356, Optics: Measuring and Testing, appropriate subclasses for devices which utilize visible light and optical principles for the measurement of angles, distances, chromatic effects and the intensity of light, flaw analysis and fiducial instruments not provided for elsewhere.
358, Facsimile and Static Presentation Processing, appropriate subclasses for facsimile systems whether the signals are transmitted by radiant energy or otherwise.
359, Optics: Systems (Including Communication) and Elements, 109 for light wave communication.
367, Communications, Electrical: Acoustic Wave Systems and Devices, appropriate subclass for apparatus for detecting objects or determining their distance or direction which are provided with means to transmit and receive sonic or supersonic waves, the sonic or supersonic waves being either generated or received by electrical means. See 87 for echo systems, subclasses 131+ for underwater systems and subclasses 115+ for distance or direction finding. (Note that the class for acoustics has similar apparatus.)
369, Dynamic Information Storage and Retrieval, 6 for combined radio and phonography systems.
375, Pulse or Digital Communication, appropriate subclass for pulse communication via radio waves. (Note: See the Class 178 search note above for Class 375, 259, 371+, for and 348+ reference).
380, Cryptography, appropriate subclasses, for cryptos:graphic communications equipment.
395, Information Processing System Organization, 80 for data processing of robot control systems.
455, Telecommunications, appropriate subclass for analog modulated carrier wave. Class 455 includes transmitters and receivers of signals having arbitrary information content, whereas Class 342 is limited to transmitter beacons, directional receivers and radar transponders of regular, periodic and in general nonvarying signals having fixed information content relating to locating or identifying a target.
505, Superconductor Technology: Apparatus, Material, Process, 150 for high temperature (T[subscrpt]c[end subscrpt] 30 K) superconducting devices, and particularly subclasses 202+ for electrical communication systems.
700, Data Processing: Generic Control Systems or Specific Applications, subclasses 1-89 for generic data processing control systems; and subclasses 90-306 for particular applications of digital data processing systems or calculating computers.
701, Data Processing: Vehicles, Navigation, and Relative Location, 200 and 300+ for computer applications in the area of navigation and determining the relative location between two points.
704, Data Processing: Speech Signal Processing, Linguistics, Language Translation and Audio Compression/Decompression, 200 for artificial intelligence systems that process speech signals.
706, Data Processing: Intelligent Processing Systems and Methods, various subclasses for artificial intelligence systems that represent, apply, and acquire knowledge.
708, Electrical Computers: Arithmetic Processing and Calculating, 1 for hybrid computers; subclasses 100+ for digital calculating computers; and subclasses 800+ for analog computers.
709, Electrical Computers and Digital Processing Systems: Multiple Computer or Process Coordinating, 200 for data transfer among a plurality of spatially distributed computers or digital data processing systems.

GLOSSARY:
ACTIVE ANTENNA
Part of the antenna which is directly coupled to free space and radiates electromagnetic energy into, or collects electromagnetic energy from, free space and is also directly coupled to a transmitter or receiver.
COMMUNICATION
The conveying or transferring or information; specifically a system, as a radio, television, telephone for conveying or transferring information.
DISTANCE
The space between two points, which may be immediately juxtaposed or widely spaced.
ELECTROMAGNETIC WAVE POLARIZATION CONVERTER
Structure which acts directly on the electromagnetic wave energy to modify the polarization pattern of the wave, for example, to change a plane polarized wave into a circularly polarized wave.
FAR FIELD
The space beyond the near field of an antenna in which radiation is essentially confined to a fixed pattern falls off inversely with the square of the distance.
FREE SPACE
Space where the movement of energy in any direction is substantially unimpeded, such as the atmosphere, the ocean or the earth.
MESSAGE
A signal used to convey intelligence, such as telephone signals (e.g., speech).
"Message" is used in a more limited sense than "signal" for the purpose of classification in this class, in that "signal" includes the transmission of control impulses for operating mechanisms other than mere signal reproducers.
NEAR FIELD
The electromagnetic field within a distance of 1 wavelength from a transmitting antenna.
ORIENTING
Changing the beam direction of an antenna with respect to some reference point.
RADAR
Acronym for radio detecting and ranging. A system that measures distance (and usually the direction) to an object by determining the amount of time required by electromagnetic energy to travel to and return from an object. Called primary radar when signals are returned by reflection. Called secondary radar when the incident signal triggers a responder beacon and causes it to transmit a second signal.
RADIANT ENERGY
The energy (partially kinetic, partially potential) associated with waves produced in free space by a source of energy, such as light wave, electromagnetic radiation (including radio waves), or neutron and similar radiation, subsonic, supersonic and sonic waves.
RADIATION
The emanation of energy into free space.
RADIATION FIELD
An electromagnetic wave whose frequency spectrum extends over a range from somewhat above the frequency of audible sound waves to somewhat below the frequency of heat and light waves. Values of 10 kilocycles and 30,000 megacycles have been given as the lower the upper limits of the range for radio waves, although values exist beyond these limits. Radio
waves as defined here exclude compressional waves, light waves, heat waves, infrared waves, ultraviolet waves, X-ray, cathode rays, gamma rays, and ion beams. The radio waves are produced by oscillations of electric change in an antenna.
SIGNAL
Control impulse, wave energy, intelligence or message, such as sing, or a noise indication agreed upon, under stood and used to convey information at a distance.
TELEGRAPHY
The transmission to a distance of signals, unlimited with respect to the extent of the message communicated, by the utilization of energy, the elements of the message being selected or composed at will according to a prearranged code.
TELEPHONY
The conversion of spoken or sound waves into energy which is transmitted a distance and reconverted into sound waves for reproduction of the speech or sounds.
TELEDYNAMICS
The transmission of signal energy for the control of apparatus or mechanisms, at a distance.

RADIO WAVE ABSORBER:
This subclass is indented under the class definition. Subject matter wherein a material or device takes up and dissipates far field radar or radio wave signals.
(1) Note. An example of a device used a radar absorber is an anechoic chamber.

SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, subclass 81 for waveguide attenuators or subclass 22 for sidewall absorption.
343, Communications: Radio Wave Antennas, 700 for radio wave antenna absorbers, per se.

For aircraft or missile:
This subclass is indented under subclass 1. Subject matter including use with air vehicles or projectiles.

For camouflage:
This subclass is indented under subclass 1. Subject matter including means to disguises an object by radar absorption.

SEE OR SEARCH THIS CLASS, SUBCLASS:
13 for radar electronic warfare.

With particular geometric configuration:
This subclass is indented under subclass 1. Subject matter wherein the absorber has significant topological structural details.

RADAR REFLECTOR:
This subclass is indented under the class definition. Subject matter wherein there are means primarily intended to echo or return far field radar signals.
(1) Note. Subject matter of this subclass excludes antenna reflectors which are part of a radar antenna with nominal radar recitation.
(2) Note. Nominal radar recitation for use with radar reflectors is included in this subclass.

SEE OR SEARCH CLASS:
343, Communications: Radio Wave Antennas, 700 for antenna reflectors, per se.

With modulation:
This subclass is indented under subclass 5. Subject matter including means to vary the amplitude, frequency of phase of a far field radar signal as it is being reflected.
(1) Note. Subject matter of this subclass excludes passive transponders.

SEE OR SEARCH THIS CLASS, SUBCLASS:
51 for passive transponders.
187 for augmenters, per se.

Corner:
This subclass is indented under subclass 5. Subject matter wherein the reflecting surfaces are arranged to intersect so as to provided a retrodirective reflection.

Inflatable or collapsible:
This subclass is indented under subclass 7. Subject matter wherein the corner reflector has the capability of being: (1) distended by gas (e.g., air); or (2) deflated of gas; or (3) folded together so as to occupy a smaller volume of space.

Decoy or tow target:
This subclass is indented under subclass 7. Subject matter wherein the corner reflectors is (1) either part of a vehicle or part of a device pulled by a vehicle which provides reflected signals which disguise the true location of the vehicle or (2) used to move the primary point of reflection.

Inflatable or collapsible:
This subclass is indented under subclass 5. Subject matter wherein the reflector has the capability of being: (1) distended by gas (e.g., air); or (2) deflated of gas; or (3) folded together so as to occupy a smaller volume of space.

With spherical lens(e.g., Luneberg lens):
This subclass is indented under subclass 5. Subject matter wherein the reflector includes a spherically shaped structure transparent to radio waves having a relative dielectric constant different from unity.
(1) Note. A Luneberg lens is a lens with a circular cross section having an index of refraction varying only in the radial direction such that a feed located on or near a surface or edge of the leans produce a major lobe diametrically opposite the feed.

SEE OR SEARCH CLASS:
343, Communications: Radio Wave Antennas, subclass 911 for an antenna with a Luneberg lens.

Chaff:
This subclass is indented under subclass 5. Subject matter wherein the reflector including thin, narrow, metallic strips of various length and frequency responses.
(1) Note. Subject matter of this subclass excludes chaff dispensing means.

SEE OR SEARCH CLASS:
102, Ammunition and Explosives, appropriate subclasses for explosive type chaff dispensers.
221, Article Dispensing, appropriate subclasses for chaff dispensers, per se.
222, Dispensing, appropriate subclasses for chaff dispensing processes or systems.

RADAR EW (ELECTRONIC WARFARE):
This subclass is indented under the class definition. Subject matter including means for intentionally interfering with systems or devices within the class, for avoiding such interference or for use in support of such means.

ECM (electronic countermeasures, i.e., jamming):
This subclass is indented under subclass 13. Subject matter including means for intentionally interfering with the transmission or reception of signals of systems or devices with the this class.

SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for decoy corner reflectors.
12 for chaff.

SEE OR SEARCH CLASS:
455, Telecommunications, subclass 1 for jamming of telecommunication signals, per se.

With repeater:
This subclass is indented under subclass 14. Subject matter including means to provide a false target replica of a received radar signal.

SEE OR SEARCH THIS CLASS, SUBCLASS:
187 for radar augmenter circuitry, per se.
353 for retransmissions of directive radio wave energy be an object in orbit about the earth.

ECCM (electronic counter-/countermeasures, i.e., anti-jamming):
This subclass is indented under subclass 13. Subject matter including means to avoid interferences with the transmission or reception of signals by systems or devices within this class.

Radar reacts to jamming:
This subclass is indented under subclass 16. Subject matter wherein a radar system being interfered with changes its mode of operation in response to the interference.

By changing frequency:
This subclass is indented under subclass 17. Subject matter wherein the radar system changes its operating frequency in response to being jammed.

By varying gain or blocking receiver:
This subclass is indented under subclass 17. Subject matter wherein the receiver gain is reduced or the receiver is gated off in response to being jammed.

SEE OR SEARCH THIS CLASS, SUBCLASS:
94 for returned signal control of radar systems by gating the radar receiver.

Detection of surveillance:
This subclass is indented under subclass 13. Subject matter including means to indicate only the presence of systematic radio signal observation means.
(1) Note. This subclass includes devices commonly called "Fuzzbuster".

BASE BAND SYSTEM:
This subclass is indented under the class definition. Subject matter wherein a radar signal extends over a broad band of frequencies rather than being at a single carrier frequency.

SEE OR SEARCH CLASS:
375, Pulse or Digital Communications, subclass 256 for pulse
transmission via radiated base band.

TRANSMISSION THROUGH MEDIA OTHER THAN AIR OR FREE SPACE:
This subclass is indented under the class definition. Subject matter wherein a radar signal is sent through a substance other than air or free space.

SEE OR SEARCH CLASS:
324, Electricity: Measuring and Testing, 323 for electrical wave subsurface geophysical exploration.
455, Telecommunications, subclass 40 for transmission of modulated carrier wave signals through the medium of earth or water, per se.

BERTHING OR DOCKING:
This subclass is indented under the class definition. Subject matter wherein a radar system is used to assist in bringing a vehicle to a space allowed for its safety or convenience between other vehicles, piers, wharves or portals.

BLIND AID:
This subclass is indented under the class definition. Subject matter wherein a radar system generates the effect of a long antenna by signal processing means rather than by the actual use of a long physical antenna.

SYNTHETIC APERTURE RADAR:
This subclass is indented under the class definition. Subject matter wherein a radar system generates the effect of a long antenna by signal processing means rather than by the actual use of a long physical antenna.
(1) Note. The long antenna is synthesized through the motion of a small antenna relative to the target with either
the antenna or the target or both moving. The signal received by the antenna is processed coherently over an integration time. The synthesized antenna length is given by the trajectory traversed by the small antenna relative to the target during the coherent integration time. Because of the two-way phase shift in forming the effective radiation pattern, the effective half-power beam-width must be computed considering twice the synthesized antenna length.

WEATHER RADAR:
This subclass is indented under the class definition. Subject matter wherein a radar systems is used to evaluate meteorological conditions.

SEE OR SEARCH THIS CLASS, SUBCLASS:
460 for storm position indicating using radio wave directive devices.

PRESENCE DETECTION ONLY:
This subclass is indented under the class definition. Subject matter wherein a radar system senses the existence of a target without quantifying any of its characteristics.

SEE OR SEARCH CLASS:
340, Communications: Electrical, 541 for intrusion detection alarm systems.

By motion detection:
This subclass is indented under subclass 27. Subject matter wherein the presence of a target is detected by sensing target movement.

SEE OR SEARCH THIS CLASS, SUBCLASS:
104 for determining velocity by radar sensing of target motion.
106 for moving target indicators (MTI), per se, where the signals from nonmoving targets are eliminated.

AIRCRAFT COLLISION AVOIDANCE SYSTEM (CAS):
This subclass is indented under the class definition. Subject matter wherein a radar signal is used to assist in preventing aircrafts from flying into one another, or other obstacles.

SEE OR SEARCH THIS CLASS, SUBCLASS:
455 for collision avoidance position indicating.

SEE OR SEARCH CLASS:
340, Communications: Electrical, subclass 903 and 961 for potential collision alerting systems.
701, Data Processing: Vehicles, Navigation, and Relative Location, subclass 17 for computerized radar for vehicle indication or guidance; subclass 223 for computerized radar ground scanners; and subclass 301 for computer avoidance collision systems.

With transponder:
This subclass is indented under subclass 29. Subject matter including a radio signal receiver-transmitter to convey the radar signal.

SEE OR SEARCH THIS CLASS, SUBCLASS:
42 for radar transponder systems, per se.

SEE OR SEARCH CLASS:
340, Communications: Electrical, 870.31 for inductively coupled signal transmitter used in continuously variable indicating systems.
375, Pulse or Digital Communications, 211 for pulse or digital signal repeaters.
455, Telecommunications, 7 for carrier wave repeaters.

Including synchronized clock:
This subclass is indented under subclass 30. Subject matter including means to operate plural transponders on separate aircraft or on the ground, on a common time base.

SEE OR SEARCH CLASS:
368, Horology: Time Measuring Systems or Devices, subclass 47 for wireless synchronization of timepieces, per se.

Included in secondary surveillance radar (SSR or air traffic control radio beacon system (ATCRBS):
This subclass is indented under subclass 30. Subject matter wherein the transponder means are part of a secondary surveillance radar (SSR) or an air traffic control radio beacon system (ATCRBS).

SEE OR SEARCH THIS CLASS, SUBCLASS:
37 for air traffic control system including SSR or ATCRBS, per se.

SEE OR SEARCH CLASS:
701, Data Processing: Vehicles, Navigation, and Relative Location, 120 for aircraft traffic control by computers.

AIRCRAFT LANDING SYSTEM:
This subclass is indented under the class definition. Subject matter wherein a radar signal is used by an airborne vehicle to enable the vehicle to land safely on the ground.

SEE OR SEARCH THIS CLASS, SUBCLASS:
37 for air traffic control system including SSR OR ATCRBS, per se.
410 for directive signal glide slope transmitters or receivers.

SEE OR SEARCH CLASS:
701, Data Processing: Vehicles, Navigation, and Relative Location, subclass 17 for computerized radar guidance of vehicle landing.

Ground control approach (GCA):
This subclass is indented under subclass 33. Subject matter including a ground radar system providing information by which aircraft approaches to landing may be directed via radio communications.

Microwave landing system (MLS):
This subclass is indented under subclass 33. Subject matter including an airfield approach microwave radar generating a guideline for landing.

AIR TRAFFIC CONTROL:
This subclass is indented under the class definition. Subject matter wherein a radar signal is used to maintain cognizance or to regulate the movement of aircraft in relation to each other or to other objects.

SEE OR SEARCH THIS CLASS, SUBCLASS:
454 for directive position signaling for plurality of vehicles.

Secondary surveillance radar (SSR) or air traffic control radar beacon system (ATCRBS):
This subclass is indented under subclass 36. Subject matter including a radar beacon-transponder means to maintain cognizance or to regulate the paths of selected vehicles within a selected area such as an airport terminal area or air route.

SEE OR SEARCH THIS CLASS, SUBCLASS:
32 for aircraft collision avoidance systems having SSR or ATCRBS.

With altitude information:
This subclass is indented under subclass 37. Subject matter wherein the transponder signal includes information about the vertical distance of an aircraft or other object above a given reference plane such as the ground or sea.

SEE OR SEARCH THIS CLASS, SUBCLASS:
118 for radar distance determination, per se.

With side lobe suppression:
This subclass is indented under subclass 37. Subject matter including circuitry means to exclude or greatly attenuate a portion of the beam for an antenna, other than the main lobe.

SEE OR SEARCH THIS CLASS, SUBCLASS:
379 for directive radio wave communications utilizing correlation techniques to eliminate side lobes.

With defruiting or degarbling:
This subclass is indented under subclass 37. Subject matter including means to eliminate random nonsynchronous unintentional return signals in a beacon system or to decode multiple overlapping signal transmission interference.

SEE OR SEARCH THIS CLASS, SUBCLASS:
159 for clutter elimination, per se.

SHIP COLLISION AVOIDANCE:
This subclass is indented under the class definition. Subject matter wherein a radar signal is used to assist in preventing naval craft from running into one another.

SEE OR SEARCH CLASS:
701, Data Processing: Vehicles, Navigation, and Relative Location, subclass 301 for computer navigation systems having collision avoidance means.

RADAR TRANSPONDER SYSTEM:
This subclass is indented under the class definition. Subject matter having means wherein the radar signal is received from an originating station, has information coded thereon or added and is retransmitted to the originating station.

SEE OR SEARCH THIS CLASS, SUBCLASS:
15 for repeater jammers which add false information to the radar signal.
30 for transponder used in aircraft collision avoidance systems.
187 for radar augmenter circuitry, per se.

Combined with primary radar system:
This subclass is indented under subclass 42. Subject matter wherein the transponder system is combined with a system in which the retransmitted (reply) signal is a reflection of the transmitted energy from the surface of the target.

Unique identity:
This subclass is indented under subclass 42. Subject matter wherein the coded radar retransmitted (reply) signal contains information used to distinguish the transponder station from all others.

IFF or SIF:
This subclass is indented under subclass 42. Subject matter including means to transmit radio signals between two stations located on ships, aircraft, or the ground, for automatic identification of particular station characteristics, such as station type (e.g., ally or enemy, bomber or fighter, etc.).
(1) Note. IFF is an acronym for Identification - Friend or Foe.
(2) Note. SIF is an acronym for Selective Identification Feature.

Navigational:
This subclass is indented under subclass 42. Subject matter wherein the transponder system is used to direct a vehicle to an intended destination.

SEE OR SEARCH THIS CLASS, SUBCLASS:
701 Data Processing: Vehicles, Navigation, and Relative Location, subclasses 200+ for computer navigation systems, per se.

Distance measuring equipment (DME):
This subclass is indented under subclass 46. Subject matter including means to provide distance information by measuring total round-trip time of transmission from an interrogator to a transponder and return, with internationally recognized signals.

SEE OR SEARCH THIS CLASS, SUBCLASS:
125 for distance determining system having an augmenter.

SEE OR SEARCH CLASS:
701, Data Processing: Vehicles, Navigation, and Relative Location, 201 for computer navigation systems.

With automatic lock-on:
This subclass is indented under subclass 47. Subject matter wherein the interrogator station includes circuit means which is self-activating to lock-on the reply signal.

With VOR/TACAN:
This subclass is indented under subclass 47. Subject matter including means operating at VHF and providing radial lines of positioning any direction as determined by bearing selection within the receiving equipment, or means operating at UHF using pulse techniques to provide a polar coordinate (rho-theta) system of navigation.
(1) Note. The VOR means emits a (variable) modulation whose phase relative to a reference modulation is different for each bearing of the receiving point from the interrogator station.
(2) Note. For TACAN the distance, (rho), function operates as DME and the bearing function is derived by rotating the ground transponder antenna so as to obtain a rotating multilobe pattern for coarse and fine information.

SEE OR SEARCH THIS CLASS, SUBCLASS:
399 for directive radio communication beacon systems including TACAN equipment and subclasses 401+ and 404+ for systems which include VOR equipment.

SEE OR SEARCH CLASS:
701, Data Processing: Vehicles, Navigation, and Relative Location, subclass 218 for computer navigation systems utilizing TACAN equipment.

With telemetry:
This subclass is indented under subclass 42. Subject matter wherein the coded transponder signal contains telemetry information.

SEE OR SEARCH CLASS:
340, Communications: Electrical, 807.1 for generic telemetering.
455, Telecommunications, appropriate subclass for telecommunications subject matter, per se.

Transponder only:
This subclass is indented under subclass 42. Subject matter
including the transponder means, per se.

SEE OR SEARCH THIS CLASS, SUBCLASS:
30 for transponders in aircraft collision avoidance systems.
37 for transponders is SSR or ATCRBS systems.

COMBINED WITH DIVERSE TYPE RADIANT ENERGY SYSTEM:
This subclass is indented under the class definition. Subject matter wherein a radar system operates in conjunction with a different type of far field radiant energy system.

With infrared device:
This subclass is indented under subclass 52. Subject matter including a device which operates using radiant energy within the wavelength range 780 to 10[supscrpt]5[end supscrpt] nanometers.

SEE OR SEARCH CLASS:
250, Radiant Energy, 338 for infrared responsive electric signaling apparatus.
356, Optics: Measuring and Testing, subclass 51 for infrared optical measuring and testing systems.
372, Coherent Light Generators, subclass 4 for infrared coherent, light generators, per se.

With laser:
This subclass is indented under subclass 52. Subject matter including a device which provides an intense, coherent, directional beam of light by stimulating electronic, ionic or molecular transitions to lower energy levels.

SEE OR SEARCH THIS CLASS, SUBCLASS:
167 for testing or calibrating radar apparatus with laser means.

SEE OR SEARCH CLASS:
356, Optics: Measuring and Testing, appropriate subclasses for laser radar, per se.
372, Coherent Light Generators, for laser apparatus, per se.

With television:
This subclass is indented under subclass 52. Subject matter including the electronic transmission and reception of transient visual images.

SEE OR SEARCH THIS CLASS, SUBCLASS:
142 for distance and direction determination with pulse modulation and CRT display.
176 for radar display circuitry, per se.

SEE OR SEARCH CLASS:
348, Television, appropriate subclass for television systems, per se.

With direction finding:
This subclass is indented under subclass 52. Subject matter including a device used to determine the direction of arrival of remotely transmitted radio signals.

SEE OR SEARCH THIS CLASS, SUBCLASS:
107 and 113, for radar device or systems which determine velocity and direction.
133 139+ and 146, for radar devices or systems which determine distance and direction.
147 for radar direction finding, per se.
350 for radio wave direction finding devices or system other than radar devices or systems.

With radio voice communication:
This subclass is indented under subclass 52. Subject matter including the transmission and reception of human voice communication by radio wave.

SEE OR SEARCH CLASS:
455, Telecommunications, for generic radio wave voice communications.

With transmission to a remote station:
This subclass is indented under subclass 52. Subject matter including radiant energy means to send a received radar signal to a distant location.

PLURAL RADAR:
This subclass is indented under the class definition. Subject matter wherein there are two or more radar systems.

TRANSMITTING INTELLIGENCE:
This subclass is indented under the class definition. Subject matter wherein the radar signal beam is used as a carrier for transmitting information in addition to radar information.

SEE OR SEARCH CLASS:
455, Telecommunications, appropriate subclass for communication systems operating at radar frequencies.

RETURN SIGNAL CONTROLS EXTERNAL DEVICE:
This subclass is indented under the class definition. Subject matter wherein the reflected radar signal is used to regulate a device separate from the radar system.

SEE OR SEARCH THIS CLASS, SUBCLASS:
73 for return signal control of the radar system.

Missile or spacecraft guidance:
This subclass is indented under subclass 61. Subject matter including control of a projectile or a space vehicle.

SEE OR SEARCH CLASS:
244, Aeronautics, 3.1 and 158+ for control of missile or spacecraft, per se.

Aircraft guidance:
This subclass is indented under subclass 61. Subject matter including means to control an air-borne vehicle's flight path.

SEE OR SEARCH CLASS:
244, Aeronautics, 175 for aircraft guidance control, per se.

With map matching:
This subclass is indented under subclass 63. Subject matter including means to compare radar data with previously stored location information to derive guidance signals.

With terrain avoidance or alarm:
This subclass is indented under subclass 63. Subject matter including means either (1) to automatically control the aircraft to follow ground contour or to prevent the aircraft from hitting ground based obstacles or (2) to develop signals to alert the aircraft operator.

SEE OR SEARCH CLASS:
340, Communications: Electrical, subclass 945 for aircraft alarm or indicating systems, per se.

Camera:
This subclass is indented under subclass 61. Subject matter including means to control the operation of a photos:graphic device.

SEE OR SEARCH CLASS:
396, Photography, 89 for automatic range and focus control for photos:graphic devices.

Gun (e.g., fire control):
This subclass is indented under subclass 61. Subject matter including means to control the operation of a firearm.

SEE OR SEARCH CLASS:
42, Firearms, appropriate subclass for firearms and firearm operation, per se.
89, Ordnance, 125 for automatic gun control, per se.
235, Registers, 400 for ordnance or weapons system computers, per se.

Proximity fuze:
This subclass is indented under subclass 61. Subject matter including means to control the operation of a fuze device as it approaches its target.

SEE OR SEARCH THIS CLASS, SUBCLASS:
166 for testing or radar apparatus which includes means to control the operation of a fuze device.

SEE OR SEARCH CLASS:
102, Ammunition and Explosives, 211 for proximity fuze, per se.

Device actuated by presence of land vehicle:
This subclass is indented under subclass 61. Subject matter including means controlled by a return signal indicative of the presence of a land vehicle.

SEE OR SEARCH THIS CLASS, SUBCLASS:
27 for radar presence detection, per se.

Radar mounted on and controls land vehicle:
This subclass is indented under subclass 61. Subject matter including radar means attached to a land vehicle and the return signal is used to control the operation of the land vehicle.

With control of brakes or steering:
This subclass is indented under subclass 70. Subject matter including regulation of the land vehicle's stopping means or its direction control means.

SEE OR SEARCH CLASS:
180, Motor Vehicles, 167 for motor vehicle control means responsive to electromagnetic radiation including radio waves reflected from a surface located apart from the vehicle.

With control of safety device (e.g., air bags):
This subclass is indented under subclass 70. Subject matter including regulation of the operation of occupant protective means.

SEE OR SEARCH CLASS:
280, Land Vehicles, subclass 735 for land vehicle air bag inflation sensors, per se.

RETURN SIGNAL CONTROLS RADAR SYSTEM:
This subclass is indented under the class definition. Subject matter wherein the reflected radar signal is used to regulate the operation of the radar system.

SEE OR SEARCH THIS CLASS, SUBCLASS:
61 for return signal control of external devices.
422 for self-orienting antenna pattern directional receivers.

Antenna control:
This subclass is indented under subclass 73. Subject matter including control by the returned signal of the radar system antenna.

SEE OR SEARCH CLASS:
343, Communications: Radio Wave Antennas, 757 for control means for moving directive antennas.

Physical orientation:
This subclass is indented under subclass 74. Subject matter including control of which way the antenna is pointing or its bearing.

With ground tracking:
This subclass is indented under subclass 75. Subject matter wherein the returned signal is used to align the antenna in an aircraft with the actual path of the aircraft along the ground.

With signal error correction:
This subclass is indented under subclass 75. Subject matter
wherein circuitry is provided to correct for errors in the returned signal.
(1) Note. Other than boresight errors.

SEE OR SEARCH THIS CLASS, SUBCLASS:
189 for radar signal correlation circuitry, per se.

SEE OR SEARCH CLASS:
714, Error Detection/Correction and Fault Detection/Recovery, appropriate subclasses for signal error detection and correction, per se.

Conical scan:
This subclass is indented under subclass 75. Subject matter wherein the rotation of the beam of the radar system describes a cone, the axis of which coincides with that of the antenna boresight.

SEE OR SEARCH THIS CLASS, SUBCLASS:
158 for radar direction determination by scanning.

Lobe switching:
This subclass is indented under subclass 75. Subject matter wherein the antenna's maximum reception orientation is periodically switched to each of two or more direction in turn.

SEE OR SEARCH THIS CLASS, SUBCLASS:
155 for radar direction determination by lobe switching.

Monopulse:
This subclass is indented under subclass 75. Subject matter including the use of a technique in which information concerning the angular location of a source or target is derivable from each pulse or signal detection by comparison of signals received simultaneously in two or more antenna beams.

SEE OR SEARCH THIS CLASS, SUBCLASS:
149 for radar direction determination with monopulse techniques.
427 for self-orienting antenna pattern monopulse directional receivers.

Beam direction by phase or frequency control:
This subclass is indented under subclass 74. Subject matter including control of which way the signal emanating from the antenna is directed by varying the phase or frequency of the signal.

SEE OR SEARCH THIS CLASS, SUBCLASS:
83 for control of the radar transmitter signal phase or frequency other than pulse repetition frequency (PRF).
154 for radar direction determination combined with beam steering.
157 for radar direction determination with frequency or phase steering.

Transmitter:
This subclass is indented under subclass 73. Subject matter including control by the returned signal of the means used to transmit the radar signal.

Signal phase or frequency other than pulse repetition frequency (PRF):
This subclass is indented under subclass 82. Subject matter including control of the radar signal phase or frequency other than pulse repetition frequency.

SEE OR SEARCH THIS CLASS, SUBCLASS:
81 for return signal control of antenna beam direction by frequency control.

Function of doppler frequency:
This subclass is indented under subclass 83. Subject matter wherein the radar transmitter frequency shift component of the returned signal which is due to the target velocity as it approaches toward or recedes from the radar.

SEE OR SEARCH THIS CLASS, SUBCLASS:
99 for doppler frequency tracking by returned signal control of radar receiver means.
104 for velocity determination be radar using doppler techniques.
171 for testing radar apparatus with simulated doppler signals.

Function of distance:
This subclass is indented under subclass 83. Subject matter wherein the radar transmitter frequency is varied as function of target distance.

With constant phase:
This subclass is indented under subclass 85. Subject matter wherein a constant phase relationship is maintained between the transmitted and returned signals.

With constant beat frequency:
This subclass is indented under subclass 85. Subject matter wherein a constant beat frequency is maintained between the transmitted and received signals.

Transmission Timing (e.g., Ring Around):
This subclass is indented under subclass 82. Subject matter including control of the transmitter signal timing.
(1) Note. Ring Around is the triggering of a radar transmitter by its own returned signal.

Receiver:
This subclass is indented under subclass 73. Subject matter including control of the means used to receive the radar signal.

Automatic target detection:
This subclass is indented under subclass 89. Subject matter including self-acting means to distinguish between the presence of a return signal from a source having predetermined characteristics versus noise or clutter.

SEE OR SEARCH THIS CLASS, SUBCLASS:
27 for presence detection only radar systems.

Gain or threshold:
This subclass is indented under subclass 89. Subject matter including control of the receiver signal strength or sensitivity.

Automatic gain control (AGC):
This subclass is indented under subclass 91. Subject matter including self-acting circuit means to adjust the receiver gain.

Constant false alarm rate (CFAR):
This subclass is indented under subclass 91. Subject matter including means specially designed to regulate false alarm caused by noise, or clutter.

SEE OR SEARCH THIS CLASS, SUBCLASS:
16 for electronic counter-countermeasures (ECCM), per se.
159 for clutter elimination, per se.

Gating:
This subclass is indented under subclass 89. Subject matter including control of a device having the ability to permit or inhibit the passage of a signal.

SEE OR SEARCH THIS CLASS, SUBCLASS:
19 for electronic counter-countermeasures by varying the gain of or blocking the radar receiver.

Automatic range tracking:
This subclass is indented under subclass 94. Subject matter including self-acting circuit means to control the timing of a gate in relation to the range of the target.

SEE OR SEARCH THIS CLASS, SUBCLASS:
47 for navigational radar transponder systems having distance measuring equipment (DME).

Automatic track while scan (ATWS):
This subclass is indented under subclass 95. Subject matter including self-acting circuit means to control a gate to keep a receiver locked on a target while continuing to receive return signals from various elements in a given region.

With automatic lock-on:
This subclass is indented under subclass 95. Subject matter including self-acting circuit means to continuously track a target.

Frequency:
This subclass is indented under subclass 89. Subject matter including control of the receiver frequency.

SEE OR SEARCH THIS CLASS, SUBCLASS:
81 for return signal control of antenna beam direction by frequency control.

Doppler frequency tracking:
This subclass is indented under subclass 98. Subject matter wherein circuitry is provided to follow variations in the doppler component of the returned signal.

SEE OR SEARCH THIS CLASS, SUBCLASS:
84 for radar transmitter control by returned signal control as a function of doppler frequency.
104 for velocity determination by radar using doppler techniques.
171 for testing radar apparatus with simulated doppler signals.

With local oscillator control:
This subclass is indented under subclass 98. Subject matter wherein the returned signal is used to regulate the frequency of the receiver local oscillator.

With filter control:
This subclass is indented under subclass 98. Subject matter
wherein the returned signal is used to vary the center frequency or the bandwidth of a receiver filter circuit.

Phase:
This subclass is indented under subclass 98. Subject matter including control of the receiver phase.

Phase locked loop:
This subclass is indented under subclass 102. Subject matter including circuit means to compare the phases of an output signal and the return signal of a target, with any phase differences converted into a correction voltage that causes the phase of the output signal to change so that it tracks the return signal.

DETERMINING VELOCITY:
This subclass is indented under the class definition. Subject matter wherein a returned radar signal is used to measure the speed of an object.

SEE OR SEARCH THIS CLASS, SUBCLASS:
324 Electricity: Measuring and Testing, subclasses 160+ for electrical speed measuring, per se.
364 Electrical Computers and Data Processing Systems, subclass 565 for computerized speed determination, per se.

Other than doppler (e.g., range rate):
This subclass is indented under subclass 104. Subject matter including velocity determination other than by measuring the doppler shift of the radar signal.
(1) Note. For example, the velocity may be obtained by measuring the rate of change of the range (i.e., range rate) of an object.

Combined with determining acceleration:
This subclass is indented under subclass 104. Subject matter including measurement of the rate of change in the velocity of the object.

SEE OR SEARCH CLASS:
702, Data Processing: Measuring, Calibrating, or Testing, subclass 141 for acceleration, determination and subclasses 142+ for speed determination.

Combined with determining distance and direction:
This subclass is indented under subclass 104. Subject matter including the radar measurement of the distance and direction of the object from a given point.

SEE OR SEARCH THIS CLASS, SUBCLASS:
109 for velocity and distance determination only.
113 for velocity and direction determination only.

With correlation:
This subclass is indented under subclass 107. Subject matter including a measurement of a relationship between the transmitted and the received radar signals.

SEE OR SEARCH THIS CLASS, SUBCLASS:
145 for radar distance determination with correlation.
189 for radar correlation circuitry, per se.
378 for directive radio communication utilizing correlation techniques.

Combined with determining distance:
This subclass is indented under subclass 104. Subject matter including the radar measurement of the distance of an object from a given point.

SEE OR SEARCH THIS CLASS, SUBCLASS:
107 for velocity, distance and direction determination.
118 for radar distance determination, per se.

With plural fixed range gates:
This subclass is indented under subclass 109. Subject matter wherein the returned signal corresponding to the respective transmitted radar pulses is applied to plural processing channels which are sequentially activated for short predetermined periods of time to represent range increments.

SEE OR SEARCH THIS CLASS, SUBCLASS:
136 for distance determination using pulse modulation with digital processing and plural fixed range gates.

With plural receiver frequency band separation:
This subclass is indented under subclass 109. Subject matter including the use of more than one frequency separation filter.

SEE OR SEARCH THIS CLASS, SUBCLASS:
116 for velocity determination with plural received frequency band separation.

With plural frequencies transmission:
This subclass is indented under subclass 109. Subject matter including transmitting two or more discrete frequencies and determining distance from changes in each of the received frequencies.

SEE OR SEARCH THIS CLASS, SUBCLASS:
116 for velocity determination with plural received frequency band separation.

Combined with determining direction (i.e., bearing):
This subclass is indented under subclass 104. Subject matter including the radar gauging of direction of an object from a given point.

SEE OR SEARCH THIS CLASS, SUBCLASS:
107 for velocity, distance and direction determination by radar systems or device.
133 139+ and 146, for radar distance and direction determination without velocity determination.
350 for direction finding with radio wave signals other than radar systems or devices.

Combined with determining sense of motion (i.e., approaching or receding):
This subclass is indented under subclass 104. Subject matter including detection of whether an object is moving toward or from a given point.

SEE OR SEARCH THIS CLASS, SUBCLASS:
28 for presence detection only with motion detection.

Digital:
This subclass is indented under subclass 104. Subject matter including digital processing of the returned radar signal.

SEE OR SEARCH THIS CLASS, SUBCLASS:
195 for radar signal digital processing, per se.

With plural received frequency band separation:
This subclass is indented under subclass 104. Subject matter
including the use of more than one frequency separation filter.

SEE OR SEARCH THIS CLASS, SUBCLASS:
111 for determining velocity combined with plural receiver frequency band separation.

With plural beams (e.g., "Janus"):
This subclass is indented under subclass 104. Subject matter including the use of two or more radar beams in making the velocity determination.
(1) Note. The "Janus"-type systems comprise two "back-to-back" antennas, respectively facing forward and rearward with nonoverlapping radiation patterns, each antenna serving to provide transmitting and receiving functions. The respective backscatter signal portions received by the antennas are added and subtracted to derive sum and difference signals from which the Doppler speed is determined.

DETERMINING DISTANCE:
This subclass is indented under the class definition. Subject matter wherein a returned radar signal is used to measure the range of an object from a reference point.

SEE OR SEARCH THIS CLASS, SUBCLASS:
458 for directive radio wave communication distance determination apparatus.

SEE OR SEARCH CLASS:
356, Optics: Measuring and Testing, 3 for range finding using visible radiation signals.
702, Data Processing: Measuring, Calibrating, or Testing, 158 for linear distance or length determination, and subclasses 163+ for rotary distance or length determination.

Miss distance indicator (MDI):
This subclass is indented under subclass 118. Subject matter including measuring the distance to an object at the closest point of approach to a reference point.

Altimeter:
This subclass is indented under subclass 118. Subject matter including determining the distance an aircraft to the earth's surface from the aircraft.

SEE OR SEARCH THIS CLASS, SUBCLASS:
38 for air traffic control systems with altitude information.

With additional indicator:
This subclass is indented under subclass 120. Subject matter including means to display information in addition to altitude.

FM type:
This subclass is indented under subclass 120. Subject matter wherein the radar altimeter carrier signal is frequency modified.

SEE OR SEARCH THIS CLASS, SUBCLASS:
128 for radar distance determination with frequency modulation circuitry, per se.
200 for frequency modulation radar circuitry, per se.

Height finder:
This subclass is indented under subclass 118. Subject matter including determining the distance from the earth's surface to an aircraft from the ground.
(1) Note. Earth curvature correction (ECC) circuits are
included in this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:
38 for air traffic control system with altitude information.

Material level within container:
This subclass is indented under subclass 118. Subject matter including determining the height of a substance in a vessel.

SEE OR SEARCH CLASS:
73, Measuring and Testing, 290 for liquid level measurement, per se.

With remote cooperating station:
This subclass is indented under subclass 118. Subject matter including determining the distance between the radar station and a station detached from the radar station using means on the detached station to interact cooperatively with the radar station's radar signal.

Triangulation:
This subclass is indented under subclass 118. Subject matter including distance determination be radar derived procedures of finding the location of a third point by taking bearings from two fixed points a known distance apart from each other or the third point; or by determining the distance from a third point to two known points.

SEE OR SEARCH THIS CLASS, SUBCLASS:
450 for position determining using triangulation by the transmission or reception of signals from two or more points from or to another point.

SEE OR SEARCH CLASS:
356, Optics: Measuring and Testing, 3.01 for triangulation by light beam.

Phase comparison:
This subclass is indented under subclass 118. Subject matter including determining distance by comparing the phase of the transmitted radar with the returned radar carried signal.

With frequency modulation:
This subclass is indented under subclass 118. Subject matter including determining distance by using a frequency modified radar carrier signal.

SEE OR SEARCH THIS CLASS, SUBCLASS:
122 for radar altitude determination with FM type altimeters.
200 for frequency modulation radar circuitry, per se.

Plural frequency transmitted:
This subclass is indented under subclass 128. Subject matter including the transmission of two or more discrete frequency modulated radar carrier signals.

Plural modulation:
This subclass is indented under subclass 128. Subject matter wherein the radar carrier signal is modified by more than one modifying signal.

Combined with pulse modulation (e.g., frequency agile):
This subclass is indented under subclass 130. Subject matter including the use of pulse modified radar carrier signals in making the distance determination.
(1) Note. Frequency agile radar is a pulse radar in which the transmitter carrier frequency is changed between pulses in a random or pseudo-random way be an amount comparable to the reciprocal of the pulse width, or multiple thereof.

SEE OR SEARCH THIS CLASS, SUBCLASS:
134 for distance determination using pulse modulation radar.
201 for radar frequency modulation combined with pulse modulation circuitry, per se.
202 for radar pulse modulation circuitry, per se.

Within pulse modulation (e.g., "CHIRP"):
This subclass is indented under subclass 131. Subject matter including modulation of the frequency within the duration of the pulse modulation.
(1) Note. "CHIRP" is a technique for pulse compression which uses linear frequency modulation during the pulse.

Combined with determining direction:
This subclass is indented under subclass 128. Subject matter including determining the direction of the object from the radar source.

SEE OR SEARCH THIS CLASS, SUBCLASS:
139 for distance and direction determination with pulse modulated radar signals.
146 for distance and direction determination with radar signals, per se.

With pulse modulation:
This subclass is indented under subclass 118. Subject matter including the use of pulse modified radar carrier signals in making the distance determination.

SEE OR SEARCH THIS CLASS, SUBCLASS:
131 for distance determination by using frequency modulation combined with pulse modulation radar.
201 for radar frequency modulation combined with pulse modulation circuitry, per se.
202 for radar pulse modulation circuitry, per se.

Digital (e.g., with counter):
This subclass is indented under subclass 134. Subject matter including digitally processing the returned radar signal.

SEE OR SEARCH THIS CLASS, SUBCLASS:
195 for radar signal digital processing, per se.

With plural fixed range gates:
This subclass is indented under subclass 135. Subject matter wherein the returned signal corresponding to respective transmitted radar pulses is applied to plural processing channels which are sequentially activated for short predetermined periods of time to represent range increments.

SEE OR SEARCH THIS CLASS, SUBCLASS:
110 for velocity determination combined with distance determination using plural fixed range gates.

With variable pulse repetition frequency (PRF) or pulse width:
This subclass is indented under subclass 134. Subject matter including changing the rate of the pulse transmission or the width of the pulse transmissions from the radar source.

With type "A" or "J" range scope:
This subclass is indented under subclass 134. Subject matter
including cathode ray tube display of the returned radar signal as ordinates vs. time as abscissas (Type "A") or with the time base as a circle and the returned signal appearing as a radial deflection from it (Type "J").

SEE OR SEARCH THIS CLASS, SUBCLASS:
55 for radar systems combined with television.
142 for radar distance and direction determination with CRT display.
176 for radar display circuitry, per se.

Combined with determining direction:
This subclass is indented under subclass 134. Subject matter including determining the direction of the object from the radar source.

SEE OR SEARCH THIS CLASS, SUBCLASS:
133 for distance and direction determination with frequency modulation radar signals.
146 for distance and direction determination with radar signal, per se.

With azimuth and elevation determination:
This subclass is indented under subclass 139. Subject matter including the object's angular measurement in a horizontal plane and in a clockwise direction and its angular position tangent to the earth's surface.

Off boresight:
This subclass is indented under subclass 139. Subject matter including means for measuring the angle between the antenna boresight and the line of sight to the target.

With CRT display:
This subclass is indented under subclass 139. Subject matter including cathode ray tube (CRT) display means.

SEE OR SEARCH THIS CLASS, SUBCLASS:
55 for radar system combined with television.
138 for radar distance determination with pulse modulation and with a type "A" or "J" range scope (CRT) display.
176 for radar display circuitry, per se.

Plural:
This subclass is indented under subclass 142. Subject matter including more than one CRT.

PPI type:
This subclass is indented under subclass 142. Subject matter wherein the display represents the signal as a bright spot, with range indicated by the distance of the spot from the center of the screen and the bearing by the radial angle of the spot.

With correlation:
This subclass is indented under subclass 118. Subject matter including a measurement of relationship between the transmitted and the received radar signals.

SEE OR SEARCH THIS CLASS, SUBCLASS:
108 for velocity, distance and direction determination with radar signal correlation.
189 for radar correlation circuitry, per se.
378 for directive radio communication utilizing correlation techniques.

Combined with determining direction:
This subclass is indented under subclass 118. Subject matter including determining the direction of the object from the radar source.

SEE OR SEARCH THIS CLASS, SUBCLASS:
133 for distance and direction determination with frequency modulated radar signals.
139 for distance and direction determination with pulse modulated radar signals.

DETERMINING DIRECTION:
This subclass is indented under the class definition. Subject matter wherein a returned radar signal is used to indicate the direction of an object from a reference point.

SEE OR SEARCH THIS CLASS, SUBCLASS:
107 and 113, for radar velocity and direction determination.
133 139 and 146, for radar distance and direction determination.

Low angle processing:
This subclass is indented under subclass 147. Subject matter including direction determination of an object at a low angle elevation with respect to the radar signal source.
(1) Note. This subclass contains circuitry to eliminate indirect radar signal returns due to reflection off the ground.

Monopulse:
This subclass is indented under subclass 147. Subject matter including the use of a radar technique in which the angular location information of a source or target object is
derivable from each pulse or signals received simultaneously in two or more antenna beams, i.e., sum and difference channels in the receiver compare the amplitudes or phases of the antenna outputs.

SEE OR SEARCH THIS CLASS, SUBCLASS:
80 for antenna physical orientation control by return signal monopulse techniques.
427 for self-orienting antenna pattern monopulse directional receivers.

With common if channel:
This subclass is indented under subclass 149. Subject matter wherein the signals for comparison share an IF channel.

With channel equalization:
This subclass is indented under subclass 149. Subject matter including means to balance the signal processing in each of the channels.

With quadrature difference processing:
This subclass is indented under subclass 149. Subject matter wherein the "in phase" sum signal is combined with the "quadrature" phase difference signals.
(1) Note. "In phase" signals have the same frequency and pass through their maximum and minimum vales of like polarity at the same instant.
(2) Note. "Quadrature" signals exist when the phase difference between them and the "in phase" signals is one-fourth of a period of 90 degrees.

SEE OR SEARCH THIS CLASS, SUBCLASS:
194 for complex signal circuitry having means to separate returned radar signals into "in phase" and "quadrature" components.

With particular antenna or waveguide:
This subclass is indented under subclass 149. Subject matter including a significant antenna apparatus or wave guide structure.

SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, appropriate subclasses for wave guides, per se.
343, Communications: Radio Wave Antennas, appropriate subclass for structural apparatus for the transmission or reception of radio waves.

Combined with beam steering:
This subclass is indented under subclass 149. Subject matter including control of which direction the signal is emanating from the antenna by varying the phase or frequency of the signal.

SEE OR SEARCH THIS CLASS, SUBCLASS:
81 for beam direction by returned signal phase or frequency control.

Lobe switching:
This subclass is indented under subclass 147. Subject matter including periodically and discretely shifting a directive radiation pattern in position so as to produce a variation of the signal at the target.

SEE OR SEARCH THIS CLASS, SUBCLASS:
79 for return signal control of the physical orientation of the radar antenna by lobe switching.

Interferometer:
This subclass is indented under subclass 147. Subject matter
including a receiving antenna system which determines the angle of arrival of the radar signal by phase comparison in the signals at several points on the antenna system.

SEE OR SEARCH THIS CLASS, SUBCLASS:
424 for self-orienting antenna pattern plural antenna tracking interferometers.

With frequency or phase steering:
This subclass is indented under subclass 147. Subject matter including means to adjust by radar signal over the elements of a given region.

Scanning:
This subclass is indented under subclass 147. Subject matter including directing the radar signal over the elements of a given region.

SEE OR SEARCH THIS CLASS, SUBCLASS:
78 for conical scan radar, per se.

CLUTTER ELIMINATION:
This subclass is indented under the class definition. Subject matter wherein unwanted echoes are cancelled from the returned radar signal.

SEE OR SEARCH THIS CLASS, SUBCLASS:
40 for elimination of unwanted transponder replies in air traffic control systems.

MTI (moving target indicator):
This subclass is indented under subclass 159. Subject matter including means to eliminate stationary targets from the returned radar signal.

SEE OR SEARCH THIS CLASS, SUBCLASS:
28 for presence detection by motion detection.
104 for determining velocity by radar sensing of target motion.

With vehicle movement compensation (e.g., AMTI (airborne MTI):
This subclass is indented under subclass 160. Subject matter including means to adjust for the movement of the craft in which the MTI radar is located.

Digital:
This subclass is indented under subclass 160. Subject matter including means to process the returned radar signal as information in the form of one of a discrete number of codes.

SEE OR SEARCH THIS CLASS, SUBCLASS:
195 for radar digital signal processing, per se.

With blind speed elimination:
This subclass is indented under subclass 160. Subject matter wherein circuitry is provided to compensate for targets having radial velocities such that the returned signals cancel each other to produce a false indication of a stationary target.

With storage tube:
This subclass is indented under subclass 160. Subject matter including a CRT that stores images on a separate screen behind the viewing screen to distinguish between target return signals having variations indicative of motion.

SEE OR SEARCH THIS CLASS, SUBCLASS:
176 for radar display circuitry, per se.

TESTING OR CALIBRATING OF RADAR SYSTEMS:
This subclass is indented under the class definition. Subject matter wherein either: (1) a determination is made how the radar apparatus is functioning, including the existence, type and location of any trouble; or (2) a comparison or measurement is made of the radar apparatus with a standard in order to: (a) determine its accuracy; (b) devise a corrected scale; (c) determine the performance level of the equipment with regard to technical order specification; or (d) generate a correction or compensation signal.

SEE OR SEARCH CLASS:
375, Pulse or Digital Communications, 224 for measuring or testing pulse communication.
455, Telecommunications, subclass 115 for measuring, testing or monitoring radio wave transmitters, per se, and subclasses 226.1+ for measuring or testing radio wave receivers, per se.

Proximity fuze:
This subclass is indented under subclass 165. Subject matter wherein the radar apparatus under test includes means to control the operation of a fuze device as it approaches its target.

SEE OR SEARCH THIS CLASS, SUBCLASS:
68 for radar return signal control of proximity fuzes.

With laser:
This subclass is indented under subclass 165. Subject matter wherein the radar test apparatus includes a device for transforming incoherent light of various frequencies of vibration into a very narrow, intense beam of coherent light.

SEE OR SEARCH THIS CLASS, SUBCLASS:
54 for radar apparatus combined with laser means.

SEE OR SEARCH CLASS:
356, Optics: Measuring and Testing, appropriate subclasses for laser radar, per se, and measuring and testing with visible light.

With noise generation:
This subclass is indented under subclass 165. Subject matter including means in the test apparatus to produce random electrical disturbances or spurious signals.

By simulation:
This subclass is indented under subclass 165. Subject matter wherein the test apparatus includes means to apply signals representative of radar return signals (e.g., simulating a radar target object) to the radar apparatus.
(1) Note. Systems for generating a simul