Method for Determining a Confidence Indicator Relating to the Trajectory Followed by a Moving Object
First Claim
1. A method for determining a confidence indicator relating to the trajectory of a moving object equipped with a receiver able to estimate the position of the moving object on the basis of the reception of navigation signals emitted by a constellation of satellites, the navigation signals being modulated by a code and the receiver comprising a local replica of the code, said method comprising the following steps:
- a. estimating the successive positions of the receiver at various instants of position measurement,b. identifying a trajectory segment passing in proximity to the successive estimated positions,c. determining the successive auto-correlation functions between the navigation signals received and the local replica of the code,d. making an assumption about the speed of displacement of the receiver over the identified trajectory segment,e. deducing from the assumption about the speed of displacement of the receiver, a Doppler delay function corresponding to the motion of the receiver,f. applying the Doppler delay function to each auto-correlation function determined in step c and deducing therefrom corrected auto-correlation functions,g. summing the corrected auto-correlation functions, the result of the summation corresponding to the corrected auto-correlation function {circumflex over (R)}(τ
) of the navigation signal,h. comparing the result of the summation of the corrected auto-correlation functions {circumflex over (R)}(τ
) with a theoretical auto-correlation function RTheo(τ
) and deducing therefrom a confidence indicator that the trajectory segment identified corresponds to the real trajectory followed by the moving object equipped with the receiver.
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Accused Products
Abstract
A method includes estimating the position of the moving object on the basis of the reception of navigation signals emitted by a constellation of satellites, the navigation signals being modulated by a code and the receiver comprising a local replica of the code. The determination of the confidence indicator consists in estimating a speed of displacement of the receiver over an identified trajectory segment, deducing therefrom a Doppler delay function corresponding to the motion of the receiver, in correcting the auto-correlation function of the GNSS navigation signal received from each satellite of the constellation by means of the delay function, in comparing the corrected auto-correlation function with a theoretical auto-correlation function by applying a quadratic criterion corresponding to the confidence indicator.
3 Citations
5 Claims
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1. A method for determining a confidence indicator relating to the trajectory of a moving object equipped with a receiver able to estimate the position of the moving object on the basis of the reception of navigation signals emitted by a constellation of satellites, the navigation signals being modulated by a code and the receiver comprising a local replica of the code, said method comprising the following steps:
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a. estimating the successive positions of the receiver at various instants of position measurement, b. identifying a trajectory segment passing in proximity to the successive estimated positions, c. determining the successive auto-correlation functions between the navigation signals received and the local replica of the code, d. making an assumption about the speed of displacement of the receiver over the identified trajectory segment, e. deducing from the assumption about the speed of displacement of the receiver, a Doppler delay function corresponding to the motion of the receiver, f. applying the Doppler delay function to each auto-correlation function determined in step c and deducing therefrom corrected auto-correlation functions, g. summing the corrected auto-correlation functions, the result of the summation corresponding to the corrected auto-correlation function {circumflex over (R)}(τ
) of the navigation signal,h. comparing the result of the summation of the corrected auto-correlation functions {circumflex over (R)}(τ
) with a theoretical auto-correlation function RTheo(τ
) and deducing therefrom a confidence indicator that the trajectory segment identified corresponds to the real trajectory followed by the moving object equipped with the receiver. - View Dependent Claims (2, 3, 4, 5)
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Specification
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- Resources
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Current AssigneeCentre National D'Etudes Spatiales, Thales SA
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Original AssigneeCentre National D'Etudes Spatiales, Thales SA
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InventorsMONNERAT, Michel, RIES, Lionel
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Granted Patent
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Time in Patent OfficeDays
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Field of Search
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US Class Current342/357.23
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CPC Class CodesG01S 19/22 Multipath-related issuesG01S 19/40 Correcting position, veloci...G01S 19/49 whereby the further system ...G01S 19/50 whereby the position soluti...
