Method and apparatus for a satellite payload and radiodetermination
First Claim
9. A method of satellite radiodetermination, comprising receiving a multiple frequency ranging signal from a first satellite;
- receiving a further ranging signal from a second satellite, deriving first ionospheric delay data from said multiple frequency ranging signal; and
estimating second ionospheric delay data for the further ranging signal on the basis of said first ionospheric delay data.
0 Assignments
0 Petitions
Accused Products
Abstract
A satellite radiodetermination system comprises global navigation service (GNSS) satellites 2 such as GPS satellites, which generate GNSS ranging signals Rn, geostationary satellites 6 which retransmit ranging signals Rg generated at a navigation land earth station (NLES) 8, including augmentation data A, and medium earth orbit (MEO) satellites 10 which generate ranging signals Rm including regional augmentation data RA transmitted from a satellite access node (SAN) 14. The regional augmentation data RA is supplied by regional augmentation systems 21a, 21b.
A navigation receiver 11 receives the ranging signals Rg, Rm, Rn and calculates ionospheric delay values for those ranging signals which are provided on dual frequencies. Using these ionospheric delay values, and optionally the regional augmentation data RA and the augmentation data A, the navigation receiver estimates ionospheric delay values for those ranging signals which are provided on single frequencies. The navigation receiver uses the ranging signals, corrected for ionospheric delay and errors indicated by the augmentation data A and regional augmentation data RA, to calculate position and time accurately.
35 Citations
27 Claims
-
9. A method of satellite radiodetermination, comprising receiving a multiple frequency ranging signal from a first satellite;
-
receiving a further ranging signal from a second satellite, deriving first ionospheric delay data from said multiple frequency ranging signal; and
estimating second ionospheric delay data for the further ranging signal on the basis of said first ionospheric delay data.
-
-
10. A satellite payload adapted for a satellite designed for a non-geostationary orbit, comprising:
-
a clock for generating a time signal;
a ranging signal generator for generating a ranging signal including timing data derived from said time signal;
relaying means for retransmitting data received by the satellite from a ground station; and
means for selectively activating and deactivating said relaying means independently of the activation of the ranging signal generator. - View Dependent Claims (26)
-
-
11. A satellite payload adapted for a satellite designed for a non-geostationary orbit, comprising:
-
a clock for generating a time signal;
a ranging signal generator for generating a ranging signal including timing data derived from said time signal;
relaying means for retransmitting received data received by the satellite from a ground station;
means for detecting an absence of said received data; and
means for generating dummy data for transmission in response to detection of said absence.
-
-
12. Apparatus for providing augmentation data for transmission by a satellite, comprising:
-
means for receiving the augmentation data;
means for providing position data relating to the position of the satellite;
determining means for determining whether the position data satisfies a predetermined criterion; and
means for selectively enabling output of said augmentation data for transmission to said satellite in response to the determining means. - View Dependent Claims (1, 2, 3, 4, 5, 6, 7, 8, 25, 24, 27)
-
-
13. A method of providing augmentation data for transmission by a satellite, comprising:
-
providing position data relating to the position of the satellite;
determining whether the position data satisfies a predetermined criterion; and
selectively enabling output of said augmentation data for transmission to a satellite in response to the result of said determining step.
-
-
14. Satellite radiodetermination apparatus, comprising:
-
means for receiving a plurality of ranging signals from a corresponding plurality of satellites; and
means for receiving ionospheric delay data, the apparatus being arranged to perform radiodetermination on the basis of said plurality of ranging signals and selectively on the basis of said ionospheric delay data in response to authorization data provided at said apparatus. - View Dependent Claims (15, 16, 17)
-
-
18. Apparatus for providing augmentation data for transmission via a satellite, comprising:
-
means for receiving said augmentation data which includes unencrypted ionospheric delay data and unencrypted differential correction data which is substantially independent of ionospheric delay;
means for encrypting said ionospheric delay data; and
means for outputting said encrypted ionospheric delay data and said unencrypted differential correction data for transmission via said satellite.
-
-
19. A method of providing ionospheric delay data and differential correction data which is substantially independent of ionospheric delay for transmission via a satellite, comprising:
-
receiving said ionospheric delay data and said differential correction data in an unencrypted form;
encrypting said ionospheric delay data; and
outputting said encrypted ionospheric delay data and said unencrypted differential correction data for transmission via said satellite.
-
-
20. Satellite radiodetermination apparatus, comprising:
-
means for receiving a plurality of ranging signals from a corresponding plurality of satellites;
means for receiving ionospheric delay data; and
means for receiving residual error data relating to residual errors in said ionospheric delay data, said satellite radiodetermination apparatus being arranged to perform radiodetermination on the basis of said plurality of ranging signals, said ionospheric delay data and said residual error data. - View Dependent Claims (21)
-
-
23. Apparatus as claimed in claim 22, wherein said means for receiving said ranging signals comprises a dispersed plurality of receiving stations, said calculating means being arranged to calculate a plurality of positions corresponding respectively to said receiving stations, and said error calculating means being arranged to calculate said errors on the basis of the respective differences between said calculated positions and predetermined positions corresponding to said receiving stations.
-
25-1. A terrestrial station including apparatus as claimed in any one of claims 12, 18, 22 or 23.
Specification