SIGNAL VERIFICATION

• US 20140100778A1
• Filed: 12/13/2013
• Published: 04/10/2014
• Est. Priority Date: 09/20/2010
• Status: Active Grant

• Current Assignee: STMicroelectronics Limited (STMicroelectronics NV)
• Original Assignee: STMicroelectronics Limited (STMicroelectronics NV)
• Inventors: Bagnall, Peter
• Granted Patent: US 9,140,561 B2
• Time in Patent Office: Days
• US Class Current: 701/531
• CPC Class Codes: G01C 21/24 specially adapted for cosmonautical navigation
• CPC Class Codes: G01S 19/20 Integrity monitoring, fault detection or fault isolation of space segment
• CPC Class Codes: G01S 19/215 issues related to spoofing
• CPC Class Codes: G01S 19/27 creating, predicting or correcting ephemeris or almanac data within the receiver

Abstract

A first position of a satellite is calculated at a first time in dependence on received orbit data corresponding to an orbit path of the satellite. An orbit path of the satellite is modeled from the first position at the first time to a second time to determine a second position of the satellite at the second time. A third position of the satellite is then calculated at the second time in dependence on the received orbit data. The second position and third position are compared to determine a validity of the orbit data.

Claims

1. A global navigation satellite system comprising a receiver configured to:

receive an indication of a validity of orbit data of a satellite determined from a comparison of a modeled position of the satellite to a time-calculation-based position; and

determine a validity of positional information associated with the orbit data when the received indication shows that the modeled position of the satellite is substantially identical to the time-calculation-based position.

2. The global navigation satellite system of claim 1, wherein the modeled position of the satellite is calculated using a first satellite position at a first time in dependence on the orbit data corresponding to an orbit path of the satellite.

3. The global navigation satellite system of claim 2, wherein the orbit path is modeled from the first satellite position at the first time to a second time to determine the modeled position of the satellite at the second time.

4. The global navigation satellite system of claim 3, wherein the orbit path is modeled using an orbit propagation model.

5. The global navigation satellite system of claim 4, wherein the orbit propagation model takes into account the effects of at least one of:

at least one gravitational body and solar pressure on the orbit path.

6. The global navigation satellite system of claim 3, wherein the time-calculation-based position is calculated using time information and the orbit data from the satellite at the second time.

7. The global navigation satellite system of claim 6, wherein the orbit data includes orbit parameters for predicting the orbit path of the satellite for a segment of flight.

8. The global navigation satellite system of claim 6, wherein the orbit data is received at a third time which falls within a period for which the orbit data describes a segment of the satellite'"'"'s path.

9. The global navigation satellite system of claim 8, wherein the first time is a time before the third time at which the orbit data is received and the second time is a time after the third time.

10. The global navigation satellite system of claim 8, wherein the first time is the start of the period for which the orbit data describes a segment of the satellite'"'"'s orbit path and the second time is the end time of the period for which the orbit data describes a segment of the satellite'"'"'s orbit path;

and wherein the satellite first position is a position at the start of the period for which the orbit data describes a segment of the satellite'"'"'s orbit path and the modeled second position and satellite second position are projected positions at the end of the period for which the orbit data describes a segment of the satellite'"'"'s orbit path.

11. The global navigation satellite system of claim 8, wherein the satellite first and second positions are calculated using position and velocity equations with orbit parameters from the orbit data as input parameters.

12. The global navigation satellite system of claim 1, wherein the indication comprises an error corresponding to a difference between the modeled position and the time-calculation-based position.

13. The global navigation satellite system of claim 12, wherein the processor is configured to determine a fault of positional information associated with the orbit data when the error of the indication exceeds a threshold.

14. The global navigation satellite system of claim 13, wherein the receiver, upon a determination of the fault of positional information, generates a signal indicating the orbit data being invalid.

15. The global navigation satellite system of claim 1, further comprising a ground control station feeding the orbit data to the satellite via a communication uplink.

16. The global navigation satellite system of claim 1, further comprising a data receiver receiving the validity of positional information associated with the orbit data for generating a position of the data receiver.

17. The global navigation satellite system of claim 16, wherein the position of the data receiver is used in a software application to determine a financial transaction value.

18. A global navigation satellite system validating orbit data of a satellite, the global navigation satellite comprising:

a communication receiver having a processor configured to;

calculate a modeled position of the satellite using a first satellite position at a first time in dependence on the orbit data corresponding to an orbit path of the satellite, the orbit path modeled from the first satellite position at the first time to a second time to determine the modeled position of the satellite at the second time;

calculate a time-based position of the satellite using time information and the orbit data from the satellite at the second time, wherein the orbit data comprises data points at a third time which falls within a period for which the orbit data describes a segment of the satellite'"'"'s path; and

transmit the modeled position and the time-based position; and

a data receiver configured to;

receive the modeled position and the time-based position;

compare the modeled position and the time-based position;

determine a validity of positional information associated with the orbit data when the received modeled position is substantially identical to the time based position; and

determine a fault of positional information associated with the orbit data when an error corresponding to a difference between the modeled position and the time-based position exceeds a threshold.

19. A global navigation satellite system validating orbit data of a satellite, the global navigation satellite comprising:

a communication receiver having a processor configured to;

calculate a modeled position of the satellite using a first satellite position at a first time in dependence on the orbit data corresponding to an orbit path of the satellite, the orbit path modeled from the first satellite position at the first time to a second time to determine the modeled position of the satellite at the second time;

calculate a time-based position of the satellite using time information and the orbit data from the satellite at the second time, wherein the orbit data comprises data points at a third time which falls within a period for which the orbit data describes a segment of the satellite'"'"'s path;

compare the modeled position and the time-based position;

determine a validity of positional information associated with the orbit data when the modeled position is substantially identical to the time based position; and

transmit the validity of positional information; and

a data receiver configured to receive the validity of positional information.

20. A global navigation satellite system comprising:

a satellite receiving orbit data from a ground control station, the satellite broadcasting the orbit data and time information;

a communication receiver having a processor configured to;

receive the orbit data and the time information;

calculate a modeled position of the satellite using a first satellite position at a first time in dependence on the orbit data corresponding to an orbit path of the satellite modeled from the first satellite position at the first time to a second time to determine the modeled position of the satellite at the second time;

calculate a time-based position of the satellite using the time information and the orbit data at the second time, wherein the orbit data comprises data points at a third time which falls within a period for which the orbit data describes a segment of the satellite'"'"'s path;

compare the modeled position and the time-based position;

determine a validity of positional information associated with the orbit data when the modeled position is substantially identical to the time based position;

determine a fault of positional information associated with the orbit data when an error corresponding to a difference between the modeled position and the time-based position exceeds a threshold; and

transmit the validity or the fault of positional information; and

a data receiver configured to receive the validity or the fault of positional information.