Method of estimating a line of sight signal propagation time using a reduced-multipath correlation function
First Claim
Patent Images
1. In a signal processing system comprising a receiver, a method of processing a data carrying carrier modulated pseudo random noise signal received from a transmitter comprising the steps of:
- receiving the data carrying signal;
providing a reference signal;
pertaining correlations on said received data carrying signal with said reference signal at a plurality of points along the correlation function Rx (τ
) of said received data carrying signal to provide a measure of the shape of the correlation function Rx (τ
);
estimating the multipath-induced contribution to the correlation function;
subtracting said estimated multipath-induced contribution from the correlation function to obtain an estimated line of sight contribution to the correlation function; and
calculating a propagation time τ
0 for said signal propagating between said transmitter and said receiver, said propagation time τ
0 being calculated from said estimated line of sight contribution to the correlation function.
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Abstract
A method and device for processing a signal are described, wherein an estimate of a multipath-induced contribution to a demodulated navigation signal is calculated and subtracted from said demodulated navigation signal to obtain an estimated line of sight contribution to said demodulated navigation signal, and a propagation time τ0 is calculated from the thus calculated line of sight contribution to said demodulated navigation signal, such that a very accurate propagation time τ0 of said navigation signal can be calculated.
27 Citations
21 Claims
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1. In a signal processing system comprising a receiver, a method of processing a data carrying carrier modulated pseudo random noise signal received from a transmitter comprising the steps of:
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receiving the data carrying signal; providing a reference signal; pertaining correlations on said received data carrying signal with said reference signal at a plurality of points along the correlation function Rx (τ
) of said received data carrying signal to provide a measure of the shape of the correlation function Rx (τ
);estimating the multipath-induced contribution to the correlation function; subtracting said estimated multipath-induced contribution from the correlation function to obtain an estimated line of sight contribution to the correlation function; and calculating a propagation time τ
0 for said signal propagating between said transmitter and said receiver, said propagation time τ
0 being calculated from said estimated line of sight contribution to the correlation function. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. In a positioning signal processing system comprising a receiver which receives a data carrying carrier modulated pseudo random noise signal from a transmitter, a method of processing the received data carrying signal to determine a propagation time τ
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0 indicative of the time it takes the received signal to propagate directly from the transmitter to the receiver, the method comprising the steps of;
providing a reference signal; performing a correlation operation on the received data carrying signal with said reference signal in order to provide a measure of the shape of the correlation function Rx (τ
);iteratively estimating the multipath-induced contribution to the correlation function and subtracting said estimated multipath-induced contribution from the correlation function to obtain an estimated line of sight contribution to the correlation function; and calculating the propagation time τ
0 from said estimated line of sight contribution to the correlation function.
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0 indicative of the time it takes the received signal to propagate directly from the transmitter to the receiver, the method comprising the steps of;
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17. In a positioning signal processing system comprising a receiver which receives a data carrying carrier modulated pseudo random noise signal from a transmitter, a method of processing the received data carrying signal to determine an estimated propagation time τ
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0 indicative of the time it takes the received signal to propagate directly from the transmitter to the receiver, the method comprising the steps of;
A. providing a reference signal; B. generating a plurality of time delayed versions of said reference signal wherein each of said delayed reference signals has been time delayed by a different amount; C. performing, for each said plurality of delayed reference signals, a correlation operation with said received data carrying signal and providing a correlation signal value indicative thereof; D. estimating a multipath-induced contribution for each of said plurality of correlation signal values; E. subtracting said estimated multipath-induced contribution from each of said plurality of correlation signal values to obtain an estimated line of sight signal contribution for each of said plurality of correlation signal values; F. estimating the propagation time τ
0 from said estimated line of sight contributions; andG. repeating said steps D, E and F until a suitable stop criterion has been reached. - View Dependent Claims (18)
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0 indicative of the time it takes the received signal to propagate directly from the transmitter to the receiver, the method comprising the steps of;
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19. In a signal processing system comprising a receiver which receives a data carrying carrier modulated pseudo random noise signal from a transmitter, a method of processing the received data carrying signal to determine an estimated propagation time τ
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0 indicative of the time it takes the received data carrying signal to propagate directly from the transmitter to the receiver, the method comprising the steps of;
providing a plurality of delayed reference signals wherein each of said delayed reference signals has been delayed in time by a different amount; performing, for each of said plurality of delayed reference signals, a correlation operation with said received data carrying signal and providing a correlation signal value indicative thereof; estimating a multipath-induced correlation signal value for each of said plurality of correlation signal values; subtracting each of said estimated multipath-induced correlation signal values from its associated one of said plurality of correlation signal values to obtain an estimated line of sight signal correlation contribution for each of said plurality of correlation signal values; and calculating the estimated propagation time τ
0 from said estimated line of sight signal correlation contributions. - View Dependent Claims (20, 21)
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0 indicative of the time it takes the received data carrying signal to propagate directly from the transmitter to the receiver, the method comprising the steps of;
Specification