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Satellite ephemeris error

A technology for satellite ephemeris and ephemeris error, which is applied in the field of determination and/or compensation of geographic location measurement errors, and can solve the problem of not providing network users.

Inactive Publication Date: 2009-06-17
整体系统公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Sometimes more detailed ephemeris data is generated to allow satellite operators to calculate maneuvering needs, but these typically take 24 hours to calculate and of course are not made available to network users

Method used

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  • Satellite ephemeris error
  • Satellite ephemeris error
  • Satellite ephemeris error

Examples

Experimental program
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Embodiment Construction

[0047] figure 1 A prior art geolocation system, generally indicated at 10, is shown. It uses two satellites 12 and 14 monitored by respective receive antennas 16 and 18 to find the position of an unknown transmitter or target 20 causing interference to the satellite communications. The transmitter 20 has a multi-lobed transmit radiation pattern, in which a main lobe 22 and two side lobes 24 are shown. One satellite 12 receives radiation in the main lobe 22: it is designated as the main satellite and the processing electronics (not shown) associated with its monitoring receiving antenna 16 is designated as the main channel. Another satellite 14 receives radiation in the side lobe 24: it is designated as the secondary satellite and the associated processing electronics at the receiving antenna 18 is designated as the secondary channel. The primary and secondary channel generated signals are used to calculate the signal correlation to determine DTO and DFO.

[0048] Both satel...

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Abstract

A method of compensating for or correcting satellite ephemeris error involves measuring time difference of arrival (TDOA) and frequency difference of arrival (FDOA) for signal replicas received via two satellites (34, 46) from calibration transmitters (42a to 42d) at different geographical locations. An initial satellite ephemeris consisting of position and velocity vectors is used to calculate ephemeris changes yielding estimated TDOA and FDOA values providing a best fit to measured TDOA and FDOA values. This provides estimated changes required to compensate for or to correct errors in the initial satellite ephemeris. The method may be iterated to deal with large ephemeris changes: i.e. the changes obtained in one iteration may be used to correct ephemeris for use as a new initial ephemeris in a following iteration. The method may be used to correct ephemeris errors in one or both satellites, if so a greater number of calibration transmitters EphemCal 1 to EphemCal 10 may be used.

Description

technical field [0001] The present invention relates to satellite ephemeris errors, and more particularly, though not exclusively, to the determination and / or compensation of geographic location measurement errors resulting therefrom. Background technique [0002] A satellite ephemeris or ephemeris set is a list of at least six parameters with associated instants of time from which it is possible to calculate the position and velocity in space of an earth-orbiting satellite. It is an important parameter for a number of reasons, but one particularly important use is in the field of geolocation, which is the location of ground-based transmitters or ground stations causing unauthorized use or interference with satellite telecommunications channels. It is necessary to obtain satellite ephemeris information before using conventional geolocation techniques. An ephemeris has a format that depends on its coordinate system. A Kepler element most commonly refers to a reference to wh...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S5/06G01S19/48
CPCG01S19/27G01S5/06G01S19/02G01S19/05G01S19/08G01S19/20G01S19/258
Inventor R·M·赖德欧特S·R·杜克D·P·哈沃思
Owner 整体系统公司