Method and apparatus for measurement processing of satellite positioning system (SPS) signals
First Claim
1. A method of measuring times of arrival of satellite signals received in a Satellite Positioning System (SPS) receiver, said method comprising:
- receiving a plurality of SPS signals from a plurality of SPS satellites;
characterizing a signal environment corresponding to the location in which said SPS receiver is located, to produce environment data which represents a manner in which SPS signals are propagated locally to said location;
measuring times of arrival of respective satellite signals from two or more satellites of said plurality of satellites; and
processing data representing said times of arrival using said environment data to produce a set of times of arrival with which to calculate a location fix for said SPS receiver.
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Abstract
A method and apparatus is disclosed for measurement processing of Satellite Positioning System (SPS) signals. A plurality of SPS signals from a corresponding plurality of SPS satellites are received in an SPS receiver. The signal environment corresponding to the location in which the SPS receiver is located is characterized to produce signal environment data. In one exemplary embodiment, an information source, such as a cellular network based database, is searched to retrieve the signal environment data given an approximate location of the GPS receiver. This approximate location may be specified by a location of a cell site which is in cellular radio communication with a cellular communication device which is co-located with the GPS receiver. One or more parameters related to signal characteristics of the satellite signals are defined. Threshold values for the parameters are determined using the signal environment data. Code phases corresponding to times of arrival of respective satellite signals from the plurality of satellites are measured. The data representing measured times of arrival are examined using threshold values for the parameters to produce a set of times of arrival from which a location fix for the GPS receiver is calculated. Other methods and apparatuses for other embodiments of the invention are also described.
159 Citations
66 Claims
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1. A method of measuring times of arrival of satellite signals received in a Satellite Positioning System (SPS) receiver, said method comprising:
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receiving a plurality of SPS signals from a plurality of SPS satellites;
characterizing a signal environment corresponding to the location in which said SPS receiver is located, to produce environment data which represents a manner in which SPS signals are propagated locally to said location;
measuring times of arrival of respective satellite signals from two or more satellites of said plurality of satellites; and
processing data representing said times of arrival using said environment data to produce a set of times of arrival with which to calculate a location fix for said SPS receiver. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of determining a position of a Satellite Positioning System (SPS) receiver, said method comprising:
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receiving an SPS signal from an SPS satellite;
determining at least a selected one of a peak-width value of a correlation output of said SPS signal or a signal-to interference ratio (SIR) of said SPS signal;
determining said position of said SPS receiver using said selected one of said peak-width value or said SIR. - View Dependent Claims (12, 13, 15, 16, 17, 18, 19, 20, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31, 59, 60, 61, 62, 65)
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14. A method of measuring times of arrival of satellite signals received in a Satellite Positioning System (SPS) receiver, said method comprising:
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receiving a plurality of SPS signals from a plurality of SPS satellites;
characterizing a signal environment corresponding to the location in which said SPS receiver is located, to produce environment data;
selecting threshold values for one or more parameters related to one or more characteristics of said satellite signals using said environment data;
measuring times of arrival of respective satellite signals from two or more satellites of said plurality of satellites, to produce a plurality of measured times of arrival; and
testing data representing said times of arrival using said threshold values for said one or more parameters to produce a set of times of arrival with which to calculate a location fix for said SPS receiver.
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24. A method of determining a location using a satellite positioning system (SPS) receiver, said method comprising:
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receiving a plurality of SPS signals from a plurality of in-view SPS satellites;
determining an integration period for each of said plurality of SPS signals, said integration period corresponding to a period of time used to perform a time-of-arrival measurement for each corresponding SPS signal;
determining a maximum correlation peak value and a correlation peak-width for each signal of said plurality of SPS signals;
determining a code phase corresponding to each said maximum correlation peak value;
determining a Doppler value for each of said plurality of SPS signals; and
determining one or more signal characteristics associated with each of said plurality of SPS signals.
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32. A SPS receiver apparatus comprising:
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an antenna for receiving SPS signals at an RF frequency from a plurality of inview satellites;
a downconverter coupled to said antenna, said downconverter reducing the RF frequency of said received SPS signals to an intermediate frequency (IF) to produce a baseband signal;
a digitizer coupled to said downconverter;
a processor coupled to said digitizer, wherein said processor is configured to;
determine a signal environment corresponding to the location in which said SPS receiver is located, to produce environment data;
select threshold values for one or more parameters related to one or more characteristics of said satellite signals using said environment data;
measure times of arrival of respective satellite signals from two or more satellites of said plurality of in-view satellites, to produce a plurality of measured times of arrival; and
test data representing said times of arrival using said threshold values for said one or more parameters to produce a set of times of arrival with which to calculate a location fix for said SPS receiver. - View Dependent Claims (33, 34, 35, 36, 37, 38, 40, 41, 42, 43, 44, 45, 47, 48, 49, 58, 63, 64, 66)
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39. A method of processing satellite positioning system (SPS) signals, said method comprising:
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determining a first possible correlation peak for a first set of SPS signals from a first SPS satellite;
determining a second possible correlation peak for said first set of SPS signals;
deriving a measurement representing a time-of-arrival of said first set of SPS signals from one of said first possible correlation peak and said second possible correlation peak.
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46. A method of processing satellite positioning system (SPS) signals, said method comprising:
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determining a signal environment data which represents a manner in which SPS signals are propagated in a location at which an SPS receiver is located, wherein said signal environment data comprises data representing at least one of multipath conditions or interference conditions for SPS signals near said location;
determining how data representing SPS signals received by said SPS receiver is processed based on said signal environment data.
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50. A method of processing satellite positioning system (SPS) signals, said method comprising:
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determining a first possible correlation peak for a first set of SPS signals;
determining a second possible correlation peak for said first set of SPS signals;
deriving a measurement representing a time-of-arrival of said first set of SPS signals from one of said first possible correlation peak and said second possible correlation peak;
transmitting from an SPS receiver which received said first set of SPS signals an identification that said first possible correlation peak and said second possible correlation peak have been determined. - View Dependent Claims (51, 52, 53, 54, 55, 57)
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56. A method of processing satellite positioning system (SPS) signals, said method comprising:
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determining from a cell based information source a signal environment which represents a manner in which SPS signals are propagated in a location at which an SPS receiver is located;
determining how data representing SPS signals received by said SPS receiver is processed based on said signal environment.
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Specification