Method and system for determining a position of a transceiver unit utilizing two-way ranging in a polystatic satellite configuration including a ground radar

• US 6,340,947 B1
• Filed: 12/22/2000
• Issued: 01/22/2002
• Est. Priority Date: 02/21/1997
• Status: Expired due to Term

• Current Assignee: Hughes Electronics Corporation (AT&T, Inc.)
• Original Assignee: Hughes Electronics Corporation (AT&T, Inc.)
• Inventors: Goliff, William, Chang, Donald C. D., Novak, John I. III, Yung, Kar W.
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US09/746,997
• Publication Number:
  US 20020003490A1
• Time in Patent Office: 396 Days
• Field of Search: 342/357.01, 342/126, 342/453, 342/36, 342/37, 342/353, 342/387
• US Class Current: 342/357.43
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 13/74 Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous 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 19/03 Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers
• CPC Class Codes: G01S 19/09 providing processing capability normally carried out by the receiver
• CPC Class Codes: G01S 19/15 Aircraft landing systems
• CPC Class Codes: G01S 19/36 relating to the receiver frond end
• CPC Class Codes: G01S 5/0054 of actual mobile position, i.e. position calculation on base station
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location

Abstract

A method and system for determining the position of an object, such as an aircraft, utilizes two-way ranging with a polystatic satellite configuration and ground radar. A ground transceiver at a first known location provides a bidirectional communication path between the ground transceiver and the object wherein the ground transceiver transmits a first ranging signal to the object and the object transmits a second ranging signal to the ground transceiver in response to the first ranging signal. A first communication transceiver at a second known location provides a first unidirectional communication path between the first communication transceiver and the object wherein the first communication transceiver performs one of transmitting a third ranging signal to the object and receiving a third ranging signal from the object in response to the first ranging signal. A second communication transceiver at a third known location for providing a second unidirectional communication path between the second communication transceiver and the object wherein the second communication transceiver performs one of transmitting a fourth ranging signal to the object and receiving a fourth ranging signal from the object in response to the first ranging signal. A signal processor determines a first, second and third path length, and determines the position of the object based on the first, second and third known locations and the first, second and third path lengths.

Claims

1. A method for determining position of an object using a ground radar and first and second satellites located in a field of view of the object, wherein the first and second satellites are separated from the object and the ground radar in a substantially vertical plane, the method comprising:

transmitting a first ranging signal from the ground radar directly to the object;

transmitting a second ranging signal from the object directly to the ground radar, in response to the object receiving the first ranging signal;

transmitting a third ranging signal from the object directly to the first satellite, in response to the object receiving the first ranging signal;

transmitting a fourth ranging signal from the first satellite directly to a satellite ground station, in response to the first satellite receiving the third ranging signal;

transmitting a fifth ranging signal from the object directly to the second satellite, in response to the object receiving the ranging signal;

transmitting a sixth ranging signal from the second satellite directly to the satellite ground station,, in response to the second satellite receiving the fifth ranging signal;

determining a first time delay corresponding to a time difference between transmission of the first ranging signal and receipt of the second ranging signal;

determining a second time delay to a time difference between transmission of the first ranging signal and receipt of the fourth ranging signal;

determining a third time delay corresponding to a time difference between transmission of the first ranging signal and receipt of the sixth ranging signal; and

determining the position of the object based on known locations of the ground radar, the first satellite, the second satellite, and the satellite ground station, and the first, second, and third time delays.

2. The method of claim 1 wherein:

the first ranging signal includes a unique code assigned to the object, wherein transmitting the second, third, and fifth ranging signal from the object is performed in response to the object receiving a first ranging signal having the unique code assigned to the object.

3. The method of claim 1 wherein:

the first, second, third, fourth, fifth, and sixth ranging signals are AB CDMA ranging signals.

4. The method of claim 1 wherein:

the ground radar is a secondary surveillance ground radar.

5. The method of claim 1 wherein:

the object is an aircraft.

6. A system for determining position of an object, the system comprising:

a satellite ground station;

a ground radar for transmitting a first ranging signal directly to the object, and for receiving a second ranging signal transmitted from the object directly to the ground radar in response to the object receiving the first ranging signal;

a first satellite located in the field of view of the object for receiving a third ranging signal transmitted from the object directly to the first satellite in response to the object receiving the first ranging signal, and for transmitting a fourth ranging signal directly to the satellite ground state in response to receiving the third ranging signal from the object;

a second satellite located in the field of view of the object for receiving a fifth ranging signal transmitted from the object directly to the second satellite in response to the object receiving the first raging signal, and for transmitting a sixth ranging signal directly to the satellite ground station in response to receiving the fifth ranging signal from the object, wherein the first and second satellites are separated from the object and the ground radar in a substantially vertical plane; and

a processor for determining a first time delay corresponding to a time difference between transmission of the first ranging signal and receipt of the second ranging signal, for determining a second time delay corresponding to a time difference between transmission of the first ranging signal and receipt of the fourth ranging signal, and for determining a third time delay corresponding to a time difference between transmission of the first ranging signal and receipt of the sixth ranging signal, wherein the processor determines the position of the object based on known locations of the ground radar, the first satellite, the second satellite, and the satellite ground station, and the first, second, and third time delays.

7. The system of claim 6 wherein:

the first ranging signal includes a unique code assigned to the object, wherein transmitting the second, third, and fifth ranging signal from the object is performed in response to the object receiving a first ranging signal having the unique code assigned to the object.

8. The system of claim 6 wherein:

the first, second, third, fourth, fifth, and sixth ranging signals are AB CDMA ranging signals.

9. The system of claim 6 wherein:

the ground radar is a secondary surveillance ground radar.

10. The system of claim 6 wherein:

the object is an aircraft.