Method and apparatus for determining the position of a vehicle

• US 4,897,661 A
• Filed: 03/31/1988
• Issued: 01/30/1990
• Est. Priority Date: 04/10/1987
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Hiraiwa, Hisaki
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): Cain, David
• Application Number:
  US07/176,289
• Time in Patent Office: 670 Days
• Field of Search: 342/357, 342/457
• US Class Current: 342/457
• CPC Class Codes: G01S 13/765 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 13/785 Distance Measuring Equipment [DME] systems
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G01S 19/00 Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
• CPC Class Codes: G01S 19/38 Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system

Abstract

There is provided a system in which a transponder is carried by each vehicle traveling on or above the earth'"'"'s surface which transmits a signal which is responsive to an interrogation signal to a ground station through two or more satellites and in the ground station, the position of the vehicle is determined from the propagation time differences of the response signals received via the satellites. In this system, the information indicative of the time lag which is required for the transponder to receive the interrogation signal and to transmit the response signal responsive to the interrogation signal is included in the response signal and then such response signal is transmitted. Thus, the time lag which is peculiar to each transponder and corresponds to the time required from the reception of the interrogation signal to the transmission of the response signal can be corrected. With this system, the positioning accuracy of each vehicle can be improved.

Claims

1. A method for communicating with and determining the position which uses a satellite-based vehicle position determining and communicating service system comprising:

transmitting with a transponder which is carried by each one of a plurality of vehicles which are traveling on or above the earth'"'"'s surface a predetermined response signal in response to reception of an interrogation signal;

receiving and retransmitting with at least two or more satellites which have repeaters in each satellite the response signal transmitted from said transponder and retransmitting the response signal, said satellites positioned at spaced orbital locations above the earth'"'"'s surface;

receiving with a ground station the response signal from said transponder which have been retransmitted from each of said satellites and said ground station determining the position of each vehicle which have a transponder on the basis of each received time of the signal from the time of transmission of said interrogation signal to the time of reception of said response signal, transmitting with said transponder of said vehicle information of the time lag of said vehicle transponder from the reception signal in said response signal, and calculating at said ground station, a position measurement difference of the vehicle by correcting each of said required times on the basis of said information of the time lag of said vehicle transponder.

2. A vehicle positioning system in a satellite-based system for communicating with and determining the position of a vehicle comprising:

a vehicle transponder which is carried by each of a plurality of vehicles which travel on or above the earth'"'"'s surface and which transmits a predetermined response signal in response to reception of an interrogation signal;

at least two or more satellites each of which have repeaters for receiving the response signal transmitted from said vehicle transponder and for retransmitting the response signal, said satellites positioned at spaced orbital locations above the earth'"'"'s surface; and

a ground station for receiving the response signal from said vehicle transponder which has been retransmitted from each of the satellites and for measuring the position of each vehicle which has a vehicle transponder using the transmit time required for signals from the transmission of said interrogation signal to the reception of said response signal, wherein said vehicle transponder has receiving means for receiving said interrogation signal, decoding means for decoding the interrogation signal received by said receiving means;

encoding means for forming the response signal responsive to the interrogation signal which is synchronized with a strobe signal which is supplied from said decoding means, transmitting means for transmitting an output signal of said encoding means and which uses a carrier having a predetermined carrier frequency, and a time lag storing means for previously storing information regarding the time lag from the reception time of said interrogation signal to the transmission time of said response signal of said vehicle transponder, and wherein the time lag information of said vehicle transponder which has been stored in said time lag storing means is included in the response signal and such response signal is then transmitted by said vehicle transponder.

3. A system according to claim 2, wherein said transponder further includes a temperature measuring means for measuring the ambient temperature of circuit devices which form said vehicle transponder, a time lag correcting means for correcting said time lag information of said vehicle transponder stored in said time lag storing means with an output signal from said temperature measuring means, and wherein the time lag information which is output from said time lag correcting means is included in the response signal and such response signal is then transmitted by said vehicle transponder.

4. A system according to claim 2, wherein a value indicative of a time difference between the time lag stored in said time lag storing means and the time lag data of a standard vehicle transponder is stored in the time lag storing means in said vehicle transponder.

5. A system according to claim 2 including a tester which can be connected to said vehicle transponder and to said time lag storing means.

6. A system according to claim 5 wherein said tester includes a receive unit which has a packet sync circuit, a transmit unit which has a transmission timing generator, and a response time difference detector, which is connected to said receive unit and said transmit unit in said vehicle transponder.