Multipath mitigation in positioning systems
AssigneeCellguide Ltd.
InventorMoshe Tocker
Life of this patent
Estimating the term…
Abstract
The location of a receiver is determined by receiving respective ranging signals from each of a plurality of transmitters at known locations. The ranging signals are cross-correlated with respective model signals to provide respective cross-correlation functions. For cross correlation functions that are determined to include multipath noise, the multipath noise is estimated and removed. Respective delays of the cross-correlation functions are estimated and the location of the receiver is inferred from the delays.
Claims17
A method of determining a location of a receiver, comprising the steps of:
- (a) using the receiver, receiving, from each of a plurality of transmitters at known locations, a respective ranging signal;
- and
- (b) for each said ranging signal:
- (i) cross-correlating said each ranging signal with a respective model signal thereby obtaining a respective cross-correlation function,
- (ii) determining whether said respective cross-correlation function includes multipath noise, by steps including:
- for each said ranging signal:
- (A) generating a template function from said respective cross-correlation function,
- (B) computing a quality measure for said respective cross-correlation function by comparing said template function to said respective cross-correlation function, and
- (C) comparing said quality measure to a predetermined threshold,
- and
- (iii) if said respective cross-correlation function includes multipath noise:
- (A) estimating said multipath noise, and
- (B) removing said multipath noise from said respective cross-correlation function.
A device for determining a location at which a plurality of ranging signals are received from a plurality of transmitters at known respective locations, comprising:
- (a) a receiver for receiving the ranging signals;
- (b) at least one cross-correlator for cross-correlating each ranging signal with a respective model signal, thereby obtaining, for each ranging signal, a corresponding cross-correlation function;
- and
- (c) a multipath mitigation unit for, for each cross-correlation function:
- (i) determining whether said each cross-correlation function includes multipath noise, by steps including:
- for each said ranging signal:
- (A) generating a template function from said respective cross-correlation function,
- (B) computing a quality measure for said respective cross-correlation function by comparing said template function to said respective cross-correlation function, and
- (C) comparing said quality measure to a predetermined threshold,
- and
- (ii) if said each cross-correlation function includes multipath noise:
- (A) estimating said multipath noise, and
- (B) removing said multipath noise from said corresponding cross-correlation function.
A non-transitory computer-readable storage medium having embodied thereon computer-readable code for mitigating multipath noise in a cross-correlation function obtained by cross-correlating a ranging signal with a model signal, the computer-readable code comprising:
- (a) program code for determining whether the cross-correlation function includes multipath noise, by steps including:
- for each said ranging signal:
- (i) generating a template function from said respective cross-correlation function,
- (ii) computing a quality measure for said respective cross-correlation function by comparing said template function to said respective cross-correlation function, and
- (iii) comparing said quality measure to a predetermined threshold;
- and
- (b) program code for, if the cross-correlation function includes multipath noise:
- (i) estimating said multipath noise;
- and
- (ii) removing said multipath noise from the cross-correlation function.
A method of determining a location of a receiver, comprising the steps of:
- (a) using the receiver, receiving, from each of a plurality of transmitters at known locations, a respective ranging signal;
- and
- (b) for each said ranging signal:
- (i) cross-correlating said each ranging signal with a respective model signal thereby obtaining a respective cross-correlation function,
- (ii) explicitly determining whether said respective cross-correlation function includes multipath noise, and
- (iii) only if, according to said determining, said respective cross-correlation function includes multipath noise:
- (A) estimating said multipath noise, and
- (B) removing said multipath noise from said respective cross-correlation function.
A device for determining a location at which a plurality of ranging signals are received from a plurality of transmitters at known respective locations, comprising:
- (a) a receiver for receiving the ranging signals;
- (b) at least one cross-correlator for cross-correlating each ranging signal with a respective model signal, thereby obtaining, for each ranging signal, a corresponding cross-correlation function;
- and
- (c) a multipath mitigation unit for, for each cross-correlation function:
- (i) explicitly determining whether said each cross-correlation function includes multipath noise, and
- (ii) only if, according to said determining, said each cross-correlation function includes multipath noise:
- (A) estimating said multipath noise, and
- (B) removing said multipath noise from said corresponding cross-correlation function.
A non-transitory computer-readable storage medium having embodied thereon computer-readable code for mitigating multipath noise in a cross-correlation function obtained by cross-correlating a ranging signal with a model signal, the computer-readable code comprising:
- (a) program code for explicitly determining whether the cross-correlation function includes multipath noise;
- and
- (b) program code for, only if, according to said determining, the cross-correlation function includes multipath noise:
- (i) estimating said multipath noise;
- and
- (ii) removing said multipath noise from the cross-correlation function.
Dependencies are inferred from the claim text.