Pseudolite positioning system and method
First Claim
1. A method of geolocating a mobile appliance from a plurality of reference signal sources in disparate communication systems comprising the steps of:
- (a) establishing a locating station in a service area;
(b) establishing the geophysical coordinates of the plurality of reference signal sources in the service area of the locating station irrespective of the communication system in which the reference signal sources are operative;
(c) determining the reference signals emitted by each of the plurality of reference signal sources;
(d) mapping the pattern of said reference signals and time differences between said reference signals emitted from the reference signal sources in the service area;
(e) providing a mobile appliance the location of which is to be determined;
(f) receiving at the mobile appliance energy from at least two of the plurality of disparate reference signal sources;
(g) determining at the mobile appliance reference signals from the received energy;
(h) determining at the mobile appliance the time difference of arrival between each pair of reference signals received from the plurality of disparate reference signal sources;
(i) transmitting the determined time differences to the locating station;
(j) receiving at the locating station the time differences transmitted by the mobile appliance;
(k) determining at the locating station the pattern of received reference signals from the received time differences;
(l) determining at the locating station an approximation of the location of the mobile appliance from a comparison of the determined pattern of received reference signals and the mapped pattern of reference signals to thereby determine the identity of the reference signal sources whose reference signals were received by the mobile appliance; and
(m) geolocating at the locating station the mobile appliance from the time differences received from the mobile appliance by TDOA techniques from the identified reference signal sources.
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Accused Products
Abstract
A system and method for determining the geolocation of autonomous mobile appliances using timing measurements from reference signals to determine position. The system and method allows the use of reference signals from disparate communication and navigation networks of which the mobile appliance may or may not be a network member. The system and method also maintains and dynamically updates its database of the location of reference signal transmitters and the reference signals emitted by the reference signal transmitters upon the detection of new reference signals or when the geolocation solution of a mobile appliance is over-determined.
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Citations
35 Claims
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1. A method of geolocating a mobile appliance from a plurality of reference signal sources in disparate communication systems comprising the steps of:
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(a) establishing a locating station in a service area;
(b) establishing the geophysical coordinates of the plurality of reference signal sources in the service area of the locating station irrespective of the communication system in which the reference signal sources are operative;
(c) determining the reference signals emitted by each of the plurality of reference signal sources;
(d) mapping the pattern of said reference signals and time differences between said reference signals emitted from the reference signal sources in the service area;
(e) providing a mobile appliance the location of which is to be determined;
(f) receiving at the mobile appliance energy from at least two of the plurality of disparate reference signal sources;
(g) determining at the mobile appliance reference signals from the received energy;
(h) determining at the mobile appliance the time difference of arrival between each pair of reference signals received from the plurality of disparate reference signal sources;
(i) transmitting the determined time differences to the locating station;
(j) receiving at the locating station the time differences transmitted by the mobile appliance;
(k) determining at the locating station the pattern of received reference signals from the received time differences;
(l) determining at the locating station an approximation of the location of the mobile appliance from a comparison of the determined pattern of received reference signals and the mapped pattern of reference signals to thereby determine the identity of the reference signal sources whose reference signals were received by the mobile appliance; and
(m) geolocating at the locating station the mobile appliance from the time differences received from the mobile appliance by TDOA techniques from the identified reference signal sources. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of updating a database of attributes of a plurality of reference signal sources comprising the steps of:
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(a) establishing a database of attributes of a plurality of known reference signal sources including;
(i) geophysical coordinates;
(ii) reference signals emitted; and
(iii) mapped pattern of time differences between reference signals emitted from each of said known reference signal source;
(b) receiving data representative of the time differences between reference signals received from a plurality of detected reference signal sources where said plurality of detected reference signal sources includes at least one of said known reference signal sources;
(c) determining if there are more than a predetermined number of received reference signals from said detected reference signal sources;
(d) determining the existence of new reference signal sources from a comparison of the time differences between said reference signals received from the plurality of detected reference signal sources and said mapped pattern of time differences from the known reference signal sources;
(e) calculating the geophysical coordinates of the new reference signal sources using TDOA techniques; and
(f) updating said database with attributes of said new reference signal sources, including;
(i) geophysical coordinates;
(ii) reference signals emitted; and
(iii) mapped pattern of time differences between reference signals emitted from each of said known reference signal source and each new reference signal source. - View Dependent Claims (16)
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17. A method of locating a mobile appliance from a plurality of reference signal sources in disparate communication systems comprising the steps of:
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(a) mapping the pattern of time differences between pairs of signals from a plurality of reference signal sources receivable in a service area in a communication system;
(b) transmitting from the mobile appliance to a locating station information representative of the time difference in arrival between pairs of signals from ones of said plurality of reference signal sources;
(c) determining at the locating station a pattern of received signals from the received time differences; and
(d) comparing the determined pattern and the mapped pattern of time differences at the locating station to determine the identity of the reference signal sources whose signals were received by the mobile appliance to thereby approximate the geolocation of the mobile appliance. - View Dependent Claims (18)
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19. A method of approximating the geolocation of a mobile appliance from a plurality of reference signal sources in disparate communication systems comprising the steps of:
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(a) mapping the pattern of amplitudes of signals and time differences between pairs of said signals from a plurality of reference signal sources receivable in a service area in a communication system;
(b) transmitting from the mobile appliance to a locating station information representative of the amplitudes of signals and the time difference in arrival between pairs of said signals from ones of said plurality of reference signal sources;
(c) determining at the locating station a pattern of received signals from the received information representative of said amplitudes and said time differences; and
(d) comparing the determined pattern and the mapped pattern of amplitudes and time differences at the locating station to determine the identity of the reference signal sources whose signals were received by the mobile appliance to thereby approximate the geolocation of the mobile appliance. - View Dependent Claims (20)
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21. In a method of geolocating a mobile appliance from a plurality of reference signal sources by TDOA techniques, the improvement of using signals from reference signal sources in disparate communication systems.
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22. In a method of geolocating a mobile appliance from a plurality of reference signal sources by TDOA techniques, the improvement of using signals from reference signal sources that are not synchronized with the mobile appliance.
- 23. In a method of geolocating a mobile appliance from a plurality of reference signal sources by TDOA techniques in which signals are transmitted from the mobile appliance to a locating station, the improvement wherein the signals transmitted to the locating station are representative of the difference in the time of arrival at the mobile appliance of the signals from the reference signal sources.
- 26. In a method of geolocating a mobile appliance operatively communicating with at least one base station in a first communication system from a plurality of reference signal sources by TDOA techniques in which signals are transmitted from the mobile appliance to a locating station, the improvement wherein the signals transmitted from the mobile to the locating station are representative of the difference in the time of arrival at the mobile appliance of pairs of signals from the reference signal sources transmitted from a second communication system which is disparate from the first communication system.
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28. A system for geolocating a mobile appliance in a service area from ones of a plurality of reference signal sources in disparate communication systems comprising:
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said mobile appliance comprising;
a receiver for receiving energy from ones of the plurality of reference signal sources, detection means for detecting reference signals from said received energy and calculating the time difference of arrival between pairs of detected reference signals; and
a transmitter for transmitting to a locating station a first signal representative of said time difference of arrival between pairs of detected reference signals;
said locating station comprising;
a receiver for receiving said first signal;
a first database comprising;
geophysical coordinates of each of the plurality of reference signal sources; and
a mapped pattern of time differences between pairs of reference signals emitted from the plurality of reference signal sources;
a first comparison means for comparing the time difference of arrival information in said first signal with the mapped pattern of time differences in the first database; and
TDOA means for geolocating the mobile appliance;
whereby the mobile appliance receives energy from ones of the plurality of reference signal sources, detects reference signals from said received energy, calculates the time difference of arrival between pairs of said reference signals, transmits a first signal representative of the time differences of arrival to the locating station; and
whereby the locating station receives said first signal, compares the received time difference of arrival information in said first signal with the mapped pattern of time differences to thereby determine the approximate location of the mobile appliance, and subsequently geolocates the mobile appliance by TDOA techniques. - View Dependent Claims (29, 30, 31, 32, 33)
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34. A system for geolocating a mobile appliance in a service area from ones of a plurality of reference signal sources in disparate communication systems comprising:
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said mobile appliance comprising;
a receiver for receiving energy from ones of the plurality of reference signal sources, detection means for detecting reference signals from said received energy and calculating the amplitude of the detected reference signals and the time difference of arrival between pairs of said detected reference signals; and
a transmitter for transmitting to a locating station a first signal representative of the amplitudes of the detected reference signals and the time difference of arrival between pairs of said detected reference signals;
said locating station comprising;
a receiver for receiving said first signal;
a first database comprising;
geophysical coordinates of each of the plurality of reference signal sources; and
a mapped pattern of amplitudes of reference signals and time differences between pairs of reference signals emitted from the plurality of reference signal sources;
a first comparison means for comparing the amplitude and time difference of arrival information in said first signal with the mapped pattern of amplitudes and time differences in the first database; and
TDOA means for geolocating the mobile appliance;
whereby the mobile appliance receives energy from ones of the plurality of reference signal sources, detects reference signals from said received energy, calculates the amplitude of detected reference signals and the time difference of arrival between pairs of said detected reference signals, transmits a first signal representative of the amplitudes and time differences of arrival to the locating station; and
whereby the locating station receives said first signal, compares the received amplitude and time difference of arrival information in said first signal with the mapped pattern of amplitude and time differences to thereby determine the approximate location of the mobile appliance, and subsequently geolocates the mobile appliance by TDOA techniques.
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35. In a method of geolocating a mobile appliance operatively communicating with at least one base station in a first communication system from a plurality of reference signal sources by TDOA techniques, the improvement wherein the mobile appliance is not synchronized with the reference signal sources
wherein the reference signal sources are in a second communication system disparate from the first communication system.
Specification