| US 7,538,717 B2 | ||
| Adaptive ground clutter cancellation | ||
| Osten Erikmats, Mölnlycke (Sweden); Svenolov Rizell, Grabo (Sweden); Per-Arne Kindberg, Molnlycke (Sweden); and Ake Andersson, Molndal (Sweden) | ||
| Assigned to SAAB AB, Linkoping (Sweden) | ||
| Appl. No. 10/538,044 PCT Filed Dec. 20, 2002, PCT No. PCT/SE02/02426 § 371(c)(1), (2), (4) Date Jun. 08, 2005, PCT Pub. No. WO2004/077093, PCT Pub. Date Sep. 10, 2004. |
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| Prior Publication US 2006/0109173 A1, May 25, 2006 | ||
| Int. Cl. G01S 13/52 (2006.01); G01S 7/292 (2006.01); G01S 7/28 (2006.01); G01S 13/00 (2006.01) | ||
| U.S. Cl. 342—159 [342/89; 342/91; 342/175; 342/195] | 15 Claims |
| 1. An airborne radar device comprising:
at least two antennas;
wherein the radar device is arranged to send out, via the antennas, radar pulses focused in main lobes;
wherein the antennas are arranged to receive reflected radar pulses, the antennas being separated from each other vertically;
means for transforming the received radar pulses into signals in the form of sequences of bins (Rk), the signals being carried
in a first channel (K1) and a second channel (K2);
clutter-suppressing means arranged in such a way that a clutter component (ec) of a certain bin (Rk) in the first channel (K1) is also found in the second channel (K2) multiplied by a complex constant (C(Rk)), where the complex constant (C(Rk)) is a quotient between complex antenna gain of the second channel (K2) and of the first channel in a direction of ground for the current bin (Rk), the clutter-suppressing means being arranged to estimate a complex constant (Ĉ(Rk)) which describes how the signals from the receiver antennas are weighted together separately for each bin (Rk) when the resultant output signal (Ψ) is formed, the estimated constant (Ĉ(Rk)) serving to suppress the clutter component (ec) in the resultant output signal (Ψ) by subtraction of the second channel (K2) from the first channel (K1) multiplied by the estimated constant (Ĉ(Rk)).
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