| US 7,529,551 B2 | ||
| Ranging and positioning system, ranging and positioning method, and radio communication apparatus | ||
| Katsuyuki Tanaka, Kanagawa (Japan); Mitsuhiro Suzuki, Chiba (Japan); Shin Saito, Kanagawa (Japan); and Katsumi Watanabe, Tokyo (Japan) | ||
| Assigned to Sony Corporation, Tokyo (Japan) | ||
| Filed on Feb. 18, 2004, as Appl. No. 10/779,628. | ||
| Claims priority of application No. 2003-052274 (JP), filed on Feb. 28, 2003. | ||
| Prior Publication US 2004/0235499 A1, Nov. 25, 2004 | ||
| Int. Cl. H04Q 7/20 (2006.01) | ||
| U.S. Cl. 455—456.6 [455/456.1; 455/67.11; 455/423; 370/328; 342/450] | 35 Claims |
| 1. A ranging and positioning system to measure a distance between two radio sets which send and receive packets to and from
each other and to determine a relative position of such two radio sets, said system comprising:
a sending radio set configured to transmit packets;
a receiving radio set configured to receive the packets and then send the packets back to the sending radio set after a certain
length of time corresponding to an integral multiple of a prescribed unit time,
wherein the sending radio set calculates the time required for the packets to be transmitted to, and, return from the receiving
radio set by subtracting the integral multiple of a prescribed unit time from the time taken from transmission of packets
to reception of packets, thereby determining the distance between the sending and receiving radio sets according to the time
required for the packets to be transmitted and return.
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