Method for determining a confidence indicator relating to the trajectory followed by a moving object
First Claim
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1. A method for determining a confidence indicator relating to a trajectory of a moving object equipped with a GNSS receiver able to estimate a position of the moving object on a basis of a reception of navigation signals emitted by a constellation of satellites, the navigation signals being modulated by a code and the GNSS receiver comprising a local replica of the code, said method comprising the following steps:
- a. estimating with the GNSS receiver successive positions of the GNSS receiver at various instants of position measurement,b. identifying with the GNSS receiver a trajectory segment passing in proximity to the successive estimated positions,c. determining with the GNSS receiver successive auto-correlation functions between the navigation signals received and the local replica of the code,d. making an assumption with the GNSS receiver about a speed of displacement of the GNSS receiver over the identified trajectory segment,e. deducing with the GNSS receiver from the assumption about the speed of displacement of the GNSS receiver, a Doppler delay function corresponding to a motion of the GNSS receiver,f. applying with the GNSS receiver the Doppler delay function to each auto-correlation function determined in step c and deducing therefrom corrected auto-correlation functions,g. summing with the GNSS receiver the corrected auto-correlation functions, a result of the summation corresponding to the corrected auto-correlation function {circumflex over (R)}(τ
) of the navigation signal, andh. comparing with the GNSS receiver 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 a real trajectory followed by the moving object equipped with the GNSS receiver.
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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.
5 Citations
8 Claims
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1. A method for determining a confidence indicator relating to a trajectory of a moving object equipped with a GNSS receiver able to estimate a position of the moving object on a basis of a reception of navigation signals emitted by a constellation of satellites, the navigation signals being modulated by a code and the GNSS receiver comprising a local replica of the code, said method comprising the following steps:
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a. estimating with the GNSS receiver successive positions of the GNSS receiver at various instants of position measurement, b. identifying with the GNSS receiver a trajectory segment passing in proximity to the successive estimated positions, c. determining with the GNSS receiver successive auto-correlation functions between the navigation signals received and the local replica of the code, d. making an assumption with the GNSS receiver about a speed of displacement of the GNSS receiver over the identified trajectory segment, e. deducing with the GNSS receiver from the assumption about the speed of displacement of the GNSS receiver, a Doppler delay function corresponding to a motion of the GNSS receiver, f. applying with the GNSS receiver the Doppler delay function to each auto-correlation function determined in step c and deducing therefrom corrected auto-correlation functions, g. summing with the GNSS receiver the corrected auto-correlation functions, a result of the summation corresponding to the corrected auto-correlation function {circumflex over (R)}(τ
) of the navigation signal, andh. comparing with the GNSS receiver 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 a real trajectory followed by the moving object equipped with the GNSS receiver. - View Dependent Claims (2, 3, 4)
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5. A method for determining a confidence indicator relating to a trajectory of a moving object equipped with a GNSS receiver able to estimate a position of the moving object on a basis of a reception of navigation signals emitted by a constellation of satellites, the navigation signals being modulated by a code and the GNSS receiver comprising a local replica of the code, said method comprising the following steps:
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a. estimating with the GNSS receiver successive positions of the GNSS receiver at various instants of position measurement, b. identifying with the GNSS receiver a trajectory segment passing in proximity to the successive estimated positions, c. determining with the GNSS receiver successive auto-correlation functions between the navigation signals received and the local replica of the code, d. measuring with the GNSS receiver a speed of displacement of the GNSS receiver over the identified trajectory segment, e. deducing with the GNSS receiver from the measured speed of displacement of the GNSS receiver, a Doppler delay function corresponding to a motion of the receiver, f. applying with the GNSS receiver the Doppler delay function to each auto-correlation function determined in step c and deducing therefrom corrected auto-correlation functions, g. summing with the GNSS receiver the corrected auto-correlation functions, a result of the summation corresponding to the corrected auto-correlation function {circumflex over (R)}(τ
) of the navigation signal, andh. comparing with the GNSS receiver 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 a real trajectory followed by the moving object equipped with the GNSS receiver. - View Dependent Claims (6, 7, 8)
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Specification
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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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Primary Examiner(s)Gregory, Bernarr
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Assistant Examiner(s)Mull, Fred H
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Application NumberUS13/763,717Publication NumberTime in Patent Office1,486 DaysField of SearchUS Class Current1/1CPC 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...
