Method and system for attitude determination of a platform using global navigation satellite system and a steered antenna

• US 7,397,422 B2
• Filed: 09/19/2006
• Issued: 07/08/2008
• Est. Priority Date: 09/19/2006
• Status: Expired due to Fees

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Tekawy, Jonathan A., DiEsposti, Raymond S.
• Primary Examiner(s): Tarcza; Thomas H.
• Assistant Examiner(s): Mull; Fred H.
• Application Number:
  US11/533,059
• Publication Number:
  US 20080068263A1
• Time in Patent Office: 658 Days
• Field of Search: 342/357.11, 342/422, 342/425, 342/426
• US Class Current: 342/357.36
• CPC Class Codes: G01S 19/53 Determining attitude

Abstract

A system and method for determining the attitude of a platform is provided. The method includes: (a) Searching and scanning for one or more GPS satellite(s) to determine initial platform position; wherein a single directionally steered antenna scans for the GPS/GNSS satellite; (b) pointing and scanning the antenna to GPS/GNSS satellite to determine a first angular measurement of a direction of a GPS/GNSS signal; (c) measuring carrier to noise ratio of the GPS/GNSS satellite; (d) dithering the single directionally steered antenna to obtain an angular measurement relative to an antenna pattern bore-sight reference; (e) repeating steps (b)-(d) to determine a second angular measurement of the direction of a second GPS signal; (f) determining the attitude error of the platform using the first and second angular measurements; (g) updating the platform position and attitude.

Claims

1. A method for determining the attitude of a platform, comprising:

(a) searching and scanning for at least one GPS/GNSS satellite to determine initial platform position;

wherein a single directionally steered antenna scans for the at least GPS/GNSS satellite;

(b) pointing and scanning the single directionally steered antenna to the at least one GPS/GNSS satellite to determine a first angular measurement of a direction of a GPS/GNSS signal;

(c) measuring carrier to noise ratio of the at least one GPS/GNSS satellite;

(d) dithering the single directionally steered antenna to obtain an angular measurement relative to an antenna pattern bore-sight reference;

(e) repeating steps (b)-(d) to determine a second angular measurement of the direction of a second GPS signal;

(f) determining attitude errors of the platform using the first and second angular measurements;

(g) updating the platform position and attitude.

2. The method of claim 1, wherein the platform is an aircraft.

3. The method of claim 1, wherein the platform is a satellite.

4. The method of claim 1, wherein the platform is a ground vehicle.

5. The method of claim 1, wherein the single directionally steered antenna is pointed in azimuth and elevation directions to the GPS/GNSS satellite using gimbaled motors.

6. The method of claim 1, wherein the single directionally steered antenna is pointed to the GPS/GNSS satellite using electronic steering.

7. The method of claim 1, wherein the single directionally steered antenna is dithered to obtain a variation in satellite signal power measurements associated with antenna gain nominal curve.

8. The method of claim 1, wherein a GPS receiver uses received power levels from the GPS/GNSS satellite to determine carrier to noise ratios.

9. The method of claim 8, wherein the GPS/GNSS receiver determines the attitude of the platform using the first and second angular measurements.

10. A system for determining the attitude of a platform, comprising:

a plurality of GPS/GNSS satellites;

a single directionally steered antenna on the platform for detecting a plurality of GPS/GNSS signals from the plurality of GPS satellites; and

a GPS/GNSS receiver with a processor, having attitude determination capability, on the platform for converting the plurality of signals into angular measurements;

wherein the angular measurements are used to determine the attitude of the platform.

11. The system of claim 10, wherein the single directionally steered antenna has a nominal curve.

12. The system of claim 10, wherein the GPS/GNSS receiver tracks and measures received power levels from the plurality of GPS/GNSS satellites on the L-band channel.

13. The system of claim 12, wherein the GPS/GNSS receiver relates the received power levels to the nominal curve of the single directionally steered antenna to measure angular direction of the plurality of satellites.

14. The system of claim 10, wherein the platform is an aircraft, a satellite and/or ground vehicle.