Method and system for estimation of mobile station velocity in a cellular system based on geographical data
First Claim
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1. A method of estimating velocity of a mobile station comprising:
- receiving, by a fixed station, a signal from a mobile terminal; and
processing said signal, by a processor operably connected to the fixed station and to a geographical database, using data from the geographical database to determine an estimate of velocity of the mobile terminal, wherein the geographical database comprises descriptive information about a geographical area,wherein said processing comprises;
analyzing said received signal using ray tracing,using a time-frequency analysis to resolve said received signal into components and identifying scatterers and scatterers'"'"' contributions to said components,identifying corresponding said scatterers and rays, and calculating Doppler estimates of said corresponding scatterers and rays, anddetermining a Doppler shift of said received signal and a delay of said Doppler shift, and using matched filtering of said received signal and said delayed Doppler shifted signal, wherein said Doppler shift is determined from a range gate;
using ray tracing to further identify scatterers by calculating a Doppler spectra from said time-frequency analysis, determining one or more biases from said Doppler estimate, and calculating a best fit of said biases to said Doppler spectra; and
determining a Doppler estimation for each said range gate using a weighted least square estimator, where said weighted least square estimator further comprises computing velocity and direction of each said scatterer in each said range gate, estimating amplitude, phase and bias, estimating a standard deviation of errors of said amplitude, phase and bias estimates, and using said standard deviation estimate to calculate said weighted least square estimate.
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Abstract
A system and method for estimating velocity of a mobile station in a wireless communication system using time-frequency signal processing and a geographical database. The geographical database is used for prediction of ray trajectory and ray power to provide an estimate of propagation delay associated with database points.
41 Citations
27 Claims
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1. A method of estimating velocity of a mobile station comprising:
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receiving, by a fixed station, a signal from a mobile terminal; and processing said signal, by a processor operably connected to the fixed station and to a geographical database, using data from the geographical database to determine an estimate of velocity of the mobile terminal, wherein the geographical database comprises descriptive information about a geographical area, wherein said processing comprises; analyzing said received signal using ray tracing, using a time-frequency analysis to resolve said received signal into components and identifying scatterers and scatterers'"'"' contributions to said components, identifying corresponding said scatterers and rays, and calculating Doppler estimates of said corresponding scatterers and rays, and determining a Doppler shift of said received signal and a delay of said Doppler shift, and using matched filtering of said received signal and said delayed Doppler shifted signal, wherein said Doppler shift is determined from a range gate; using ray tracing to further identify scatterers by calculating a Doppler spectra from said time-frequency analysis, determining one or more biases from said Doppler estimate, and calculating a best fit of said biases to said Doppler spectra; and determining a Doppler estimation for each said range gate using a weighted least square estimator, where said weighted least square estimator further comprises computing velocity and direction of each said scatterer in each said range gate, estimating amplitude, phase and bias, estimating a standard deviation of errors of said amplitude, phase and bias estimates, and using said standard deviation estimate to calculate said weighted least square estimate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for enhanced location estimation comprising:
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receiving, by a fixed station, a signal from a mobile terminal; processing said signal by a processor operably connected to the fixed station and to a geographical database, using data from the geographical database to determine an estimate of velocity of the mobile terminal, wherein the geographical database comprises descriptive information about a geographical area, wherein said processing comprises; analyzing said received signal using ray tracing, using a time-frequency analysis to resolve said received signal into components and identifying scatterers and scatterers'"'"' contributions to said components, identifying corresponding said scatterers and said rays, and calculating Doppler estimates of said corresponding scatterers and rays, and determining a Doppler shift of said received signal and a delay of said Doppler shift, and using matched filtering of said received signal and said delayed Doppler shifted signal, wherein said Doppler shift is determined from a range gate; using ray tracing to further identify scatterers by calculating a Doppler spectra from said time-frequency analysis, determining one or more biases from said Doppler estimate, and calculating a best fit of said biases to said Doppler spectra; determining a Doppler estimation for each said range gate using a weighted least square estimator, where said weighted least square estimator further comprises computing velocity and direction of each said scatterer in each said range gate, estimating amplitude, phase and bias, estimating a standard deviation of errors of said amplitude, phase and bias estimates, and using said standard deviation estimate to calculate said weighted least square estimate; integrating said velocity estimate and location measurement data; and calculating an enhanced location estimate using said integration. - View Dependent Claims (15)
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16. A system for estimating velocity of a mobile station comprising:
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a mobile station capable of transmitting signals; a fixed station capable of receiving signals transmitted by at least said mobile station; a geographical database, comprising descriptive information about a geographical area; a processor operably connected to said fixed station and said geographical database, to; process a signal sent from said mobile station to said fixed station with data from said geographical database to determine an estimate of velocity of said mobile station, wherein said signal is processed using time-frequency signal processing and ray tracing, to resolve said signal into component Parts and identify scatterers and scatterers'"'"' contributions to said components and to calculate Doppler estimates of rays corresponding to scatterers using matched filtering of said Doppler estimate and of a shifted Doppler estimate; determine said shifted Doppler estimate using a range gate; and process said signal to calculate a best fit of biases to a Doppler spectra, where said Doppler spectra is calculated from said time-frequency analysis using said ray tracing to identify said scatterers, and where said biases are calculated from said Doppler estimate. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A system for estimating velocity of a mobile station comprising:
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a mobile station capable of transmitting signals; a fixed station capable of receiving signals transmitted by at least said mobile station; a geographical database, comprising descriptive information about a geographical area; a processor operably connected to said fixed station and said geographical database, to; process a signal sent from said mobile station to said fixed station with data from said geographical database to determine an estimate of velocity of said mobile station, wherein said signal is processed using time-frequency signal processing and ray tracing, to resolve said signal into component parts and identify scatterers and scatterers'"'"' contributions to said components and to calculate Doppler estimates of rays corresponding to scatterers using matched filtering of said Doppler estimate and of a shifted Doppler estimate; determines said shifted Doppler estimate using a range gate; and processes said signal to determine a weighted least squares estimator, where said weighted least squares estimator is calculated from the velocity and direction of each said scatterer in each said range gate, an estimate of amplitude, phase and bias, and an estimate of standard deviation of errors of said amplitude, phase and bias.
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Specification