METHOD FOR ESTIMATING THE LEVEL OF ERROR IN SATELLITE GEOLOCATION MEASUREMENTS AND FOR MONITORING THE RELIABILITY OF SAID ESTIMATIONS AND ASSOCIATED DEVICE

• US 20150355339A1
• Filed: 11/15/2013
• Published: 12/10/2015
• Est. Priority Date: 11/16/2012
• Status: Active Grant

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: VAN DEN BOSSCHE, Mathias
• Granted Patent: US 10,012,737 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01S 19/20 Integrity monitoring, fault detection or fault isolation of space segment
• CPC Class Codes: G01S 19/22 Multipath-related issues
• CPC Class Codes: G01S 19/24 Acquisition or tracking or demodulation of signals transmitted by the system synchronisation aspects of direct sequence spread spectrum modulation H04B1/7073

Abstract

In the field of satellite global navigation, a method is provided for estimating the level of error in global navigation satellite measurements and for ensuring the reliability of these estimations, implemented by a global navigation device in which local errors are detected by said global navigation device and errors associated with the satellites are detected by a ground segment.

Claims

1. A method for estimating and controlling integrity parameters for global navigation satellite measurements implemented by a global navigation device, wherein local errors are detected by said global navigation device and errors associated with the satellites are detected by a ground segment.

2. The method as claimed in claim 1, further comprising:

a step Etp1 of calculating local errors σ

_loc,i;

a step Etp2 of constructing an error budget from the local errors and errors associated with the satellites;

a step Etp3 of monitoring the error budget; and

a step of calculating integrity parameters using the errors estimated in the preceding steps.

3. The method as claimed in the preceding claim 2, wherein step Etp1 comprises:

a step Etp11 of calculating the error dispersion due to thermal noise;

a step Etp12 of calculating the noise due to multipath effects; and

a step Etp13 of calculating local error.

4. The method as claimed in claim 3, wherein the noise due to multipath effects is determined using the formula:

5. The method as claimed in claim 2, wherein the error budget is obtained by quadratic summation of the local errors and errors associated with the satellites.

6. The method as claimed in claim 2, wherein step Etp2 comprises:

a step Etp21 of accounting for ionospheric error;

a step Etp22 of accounting for tropospheric error;

a step Etp23 of accounting for orbit/clock error; and

a step Etp23 of calculating the error budget.

7. The method as claimed in claim 6, wherein the global navigation device is a bi-frequency device and the ionospheric error is calculated using the formula:

8. The method as claimed in claim 2 wherein step Etp3 comprises:

a step Etp31 of estimating the position of the global navigation device;

a step Etp32 of estimating pseudorange residues; and

a step Etp33 of rejecting measurements incompatible with the estimated error budgets.

9. The method as claimed in claim 2, wherein the integrity parameters are calculated by defining a radius of protection that must be smaller than a preset threshold value.

10. The method as claimed in claim 2, wherein the integrity parameters are determined by calculating directly the risk of exceeding alarm values.

11. The method as claimed in claim 1, wherein the estimations of local errors are validated with a robust algorithm.

12. The method as claimed in claim 1, wherein the calculation of the integrity parameters is carried out on the basis of previously validated estimations.

13. A global navigation device configured to implement the method as claimed in claim 1.