System for determining position from suppressed carrier radio waves

• US 5,384,574 A
• Filed: 03/15/1993
• Issued: 01/24/1995
• Est. Priority Date: 03/01/1982
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Western Atlas International Incorporated (Northrop Grumman Corporation)
• Inventors: Counselman, III, Charles C.
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US08/031,649
• Time in Patent Office: 680 Days
• Field of Search: 342/352, 342/357, 342/463, 342/464, 342/465
• US Class Current: 342/357.26
• CPC Class Codes: G01C 15/00 Surveying instruments or accessories not provided for in groups G01C1/00 - G01C13/00
• CPC Class Codes: G01S 19/35 Constructional details or hardware or software details of the signal processing chain
• CPC Class Codes: G01S 19/44 Carrier phase ambiguity resolution; Floating ambiguity; LAMBDA [Least-squares AMBiguity Decorrelation Adjustment] method

Abstract

The invention is a system for determining position by measuring phases of suppressed carrier-waves implicit in radio signals received from earth-orbiting satellites which include receiving the signals from a plurality of satellites simultaneously by means of an omnidirectional antenna, separating the received signals into first and second portions representing different radio-frequency bands and correlating the first portion with the second portion to obtain data representing the phases of the carrier-waves for a plurality of the satellites simultaneously.

Claims

1. In a method of determining position by measuring phases of suppressed carrier-waves implicit in radio signals received from earth-orbiting satellites, an improvement comprising:

(a) receiving said signals from a plurality of said satellites simultaneously by means of an omnidirectional antenna;

(b) separating said received signals into first and second portions representing different radio-frequency bands; and

(c) correlating said first portion with said second portion to obtain data representing the phases of said carrier-waves for a plurality of said satellites simultaneously.

2. The method of claim 1 wherein said signals have Doppler shifts and satellite-specific estimates of said Doppler shifts are utilized in obtaining said data representing the phases of said carrier waves.

3. The method of claim 1 wherein said signals have modulation, and said first and second portions are similar by virtue of said modulation.

4. The method of claim 3 wherein said modulation may be encrypted.

5. In an apparatus for determining position by measuring phases of suppressed carrier-waves implicit in radio signals received from earth-orbiting satellites, an improvement comprising:

(a) an omnidirectional antenna for receiving said signals from a plurality of said satellites simultaneously;

(b) a frequency band separator for separating said received signals into first and second portions representing different radio-frequency bands; and

(c) a correlator for correlating said first portion with said second portion to obtain data representing the phases of said carrier-waves for a plurality of said satellites simultaneously.

6. The apparatus of claim 5 wherein said signals have Doppler shifts and satellite-specific estimates of said Doppler shifts are utilized in obtaining said data representing the phases of said carrier waves.

7. The apparatus of claim 5 wherein said signals have modulation, and said first and second portions are similar by virtue of said modulation.

8. The apparatus of claim 7 wherein said modulation may be encrypted.

9. In a method of determining relative positions of a plurality of points by measuring phases of suppressed carrier-waves implicit in radio signals received at said points from earth-orbiting satellites, an improvement comprising:

(a) receiving said signals from a plurality of said satellites simultaneously by means of an omnidirectional antenna at each said point;

(b) separating said signals received at each said point into first and second portions representing different radio-frequency bands; and

(c) correlating said first portion with said second portion to obtain data representing the phases of said carrier-waves for a plurality of said satellites simultaneously, at each said point.

10. The method of claim 9 wherein said signals have Doppler shifts and satellite-specific estimates of said Doppler shifts are utilized in obtaining said data representing the phases of said carrier waves.

11. The method of claim 9 wherein said signals have modulation, and said first and second portions are similar by virtue of said modulation.

12. The method of claim 11 wherein said modulation may be encrypted.

13. In an apparatus for determining relative positions of a plurality of points by measuring phases of suppressed carrier-waves implicit in radio signals received at said points from earth-orbiting satellites, an improvement comprising:

(a) an omnidirectional antenna at each said point for receiving said signals from a plurality of said satellites simultaneously;

(b) a frequency band separator for separating said signals received at each said point into first and second portions representing different radio-frequency bands; and

(c) a correlator for correlating said first portion with said second portion to obtain data representing the phases of said carrier waves for a plurality of satellites simultaneously, at each said point.

14. The apparatus of claim 13 wherein said signals have Doppler shifts and satellite-specific estimates of said Doppler shifts are utilized in obtaining said data representing the phases of said carrier waves.

15. The apparatus of claim 13 wherein said signals have modulation, and said first and second portions are similar by virtue of said modulation.

16. The apparatus of claim 15 wherein said modulation may be encrypted.

17. A method of determining position using radio signals received from earth-orbiting satellites, when said signals have suppressed carrier-waves, said method comprising:

(a) receiving said signals from a plurality of said satellites simultaneously by means of an omnidirectional antenna;

(b) separating said received signals into first and second portions representing different radio-frequency bands;

(c) correlating said first portion with said second portion to obtain data representing the phases of said carrier-waves for a plurality of said satellites simultaneously; and

(d) determining position from said plural-satellite phase data.

18. The method of claim 17 wherein said signals have Doppler shifts and satellite-specific estimates of said Doppler shifts are utilized in obtaining said data representing the phases of said carrier waves.

19. The method of claim 17 wherein said signals have modulation, and said first and second portions are similar by virtue of said modulation.

20. The method of claim 19 wherein said modulation may be encrypted.

21. Apparatus for determining position using radio signals received from earth-orbiting satellites, when said signals have suppressed carrier-waves, said apparatus comprising:

(a) an omnidirectional antenna for receiving said signals from a plurality of said satellites simultaneously;

(b) a frequency band separator for separating said received signals into first and second portions representing different radio-frequency bands;

(c) a correlator for correlating said first portion with said second portion to obtain data representing the phases of said carrier-waves for a plurality of said satellites simultaneously; and

(d) means for determining position from said plural-satellite phase data.

22. The apparatus of claim 21 wherein said signals have Doppler shifts and satellite-specific estimates of said Doppler shifts are utilized in obtaining said data representing the phases of said carrier waves.

23. The apparatus of claim 21 wherein said signals have modulation, and said first and second portions are similar by virtue of said modulation.

24. The apparatus of claim 23 wherein said modulation may be encrypted.

25. A method of determining the relative positions of a plurality of points using radio signals received at said points from earth-orbiting satellites, when said signals have suppressed carrier-waves, said method comprising:

(a) receiving said signals from a plurality of said satellites simultaneously by means of an omnidirectional antenna at each said point;

(b) separating said received signals at each said point into first and second portions representing different radio-frequency bands;

(c) correlating said first portion with said second portion to obtain data representing the phases of said carrier-waves for a plurality of said satellites simultaneously, at each said point; and

(d) combining said plural-satellite phase data from said plurality of points to determine said relative positions.

26. The method of claim 25 wherein said signals have Doppler shifts and satellite-specific estimates of said Doppler shifts are utilized in obtaining said data representing the phases of said carrier waves.

27. The method of claim 25 wherein said signals have modulation, and said first and second portions are similar by virture of said modulation.

28. The method of claim 27 wherein said modulation may be encrypted.

29. Apparatus for determining the relative positions of a plurality of points using radio signals received at said points from earth-orbiting satellites, when said signals have suppressed carrier-waves, said method comprising:

(a) an omnidirectional antenna at each said point for receiving said signals from a plurality of said satellites simultaneously;

(b) a frequency band separator for separating said received signals, received at each said point, into first and second portions representing different radio-frequency bands;

(c) a correlator for correlating said first portion with said second portion to obtain data representing the phases of said carrier-waves for a plurality of said satellites simultaneously, at each said point; and

(d) means for combining said plural-satellite phase data from said plurality of points to determine said relative positions.

30. The apparatus of claim 29 wherein said signals have Doppler shifts and satellite-specific estimates of said Doppler shifts are utilized in obtaining said data representing the phases of said carrier waves.

31. The apparatus of claim 29 wherein said signals have modulation, and said first and second portions are similar by virtue of said modulation.

32. The apparatus of claim 31 wherein said modulation may be encrypted.