GPS system for tracking an object of interest and method for using the same
An assisted global positioning system (AGPS) for tracking a movable object of interest is disclosed. The system comprises a service center for calculating a tag location, a plurality of ground base stations, a plurality of beacons adapted to transmit individual ID data, and at least one GPS-based smart tag releasably affixed to the movable object. The system components are interconnected by means of one or more communication links. The service center is adapted for inquiring the tag and receiving a response from the tag constituting pseudo-ranges according to a predetermined protocol.
1. An assisted global positioning system (AGPS) for tracking a movable object of interest; said system comprising:
at least one GPS-based smart tag releasably affixed to said movable object, said smart tag interconnected to a ground base station and a plurality of GPS satellites by means of one or more communication links, wherein the ground base station and the plurality of GPS satellites emit retrievable scheduled signals, and said smart tag is configured to:
(1) remain in a cold standby condition prior to receiving an ID signal of a nearest one of a plurality of beacons, each beacon adapted to transmit a respective ID signal identifying said beacon,
(2) wake up upon receiving the ID signal from the nearest beacon,
(3) calculate a set of pseudo ranges and transmit the set of pseudo-ranges from said smart tag via the ground base station to a service center, the service center adapted to provide said smart tag with an assisted data, and
(4) be restored to a cold standby condition after transmitting the set of pseudo-ranges;
wherein said service center is adapted to communicate with said tag and receiving the set of pseudo-ranges, and calculating a location of the tag by triangulation of the time delays of said signals received from said satellites.
2. The system according to claim 1 , wherein said service center is further adapted to:
a. receive a beacon ID data;
b. determine an approximate tag location according to both (i) said received beacon ID and (ii) signal measurement data; and
c. generate and transmit the assisted data related with the determined tag approximate location.
3. The system according to claim 2 , wherein said assisted data comprises at least one element selected from the group consisting of almanac, ephemeris, transmission frequency, and encoding data.
4. The system according to claim 1 , wherein said smart tag comprises:
a. a GPS receiver adapted to receive signals broadcasted by the plurality of GPS satellites and calculating a plurality of pseudo-ranges from said tag to said satellites by processing said signals; and,
b. an RF transceiver adapted to:
(i) wake up when beacon transmission has been sensed;
(ii) measure a signal transmitted by said beacon;
(iii) extract said beacon ID data from said signal;
(iv) receive said assisted data,
(v) transmit said calculated pseudo-ranges; and
(vi) retransmit said beacon ID and signal measurement data.
5. The system according to claim 4 , wherein said RF transceiver comprises circuits adapted to identify the beacon and measure beacon signal parameters selected from the group consisting of a received signal strength indicator and a phase delay, or any combination thereof.
6. The system according to claim 1 , wherein each said ground base station comprises:
a. an RF-transceiver adapted to retransmit said assisted data to said smart tag and receiving said calculated pseudo-ranges, beacon ID and signal measurement data from said smart tag; and
b. an Ethernet interface adapted to retransmit said pseudo-ranges, said ID and signal measurement data to the service center.
7. The system according to claim 1 , wherein said communication link between said tag and said ground base station is wireless.
8. The system according to claim 1 , wherein said system comprises smart tags selected from the group consisting of optical radiation tags, RF triangulation tags, gate crossing detection tags, and any combination thereof.
9. The system according to claim 1 , wherein said smart tag further comprises at least one element selected from the group consisting of microcontroller unit, a motion sensor, and a plurality of I/O lines.
10. A method for tracking a location of a smart tag, said method comprising the steps of:
(a) providing the system according to claim 1 ;
(b) measuring a signal of a nearest beacon device and deriving an ID and signal measurements data from said signal;
(c) transferring said ID and signal measurement data to said service center;
(d) determining an approximate location of said tag;
(e) calculating assisted data according to the approximate tag location;
(f) transmitting assisted data according to tag approximate location;
(g) searching satellite-broadcasted signal according to said assisted data;
(h) receiving satellite-broadcasted signals,
(i) calculating pseudo-ranges from said smart tag to said satellites;
transferring said pseudo-ranges from said smart tag via a ground base station to the service center.
11. The method according to claim 10 wherein said method further comprises the steps of (i) waking up said smart tag in a cold standby condition, prior to receiving ID and signal measurement data of a nearest beacon device; and (ii), restoring said smart tag to a cold standby condition after transferring said pseudo-ranges from said smart tag via a ground base station to a service center.
12. The method according to claim 10 , wherein said step of calculating said location of said tag is performed by triangulating the said pseudo-ranges.
13. The method according to claim 10 , wherein said step of downloading assisted data comprises downloading almanac, empheris, transmission frequency, and encoding data.
14. The method according to claim 10 , wherein said step of determining an approximate location of the tag is performed according to the beacon location.
15. The method according to claim 10 , wherein said step of determining an approximate location of said tag is performed by triangulating the smart tag position using beacon signal measurement data.
16. The method according to claim 10 , wherein said step of measuring said beacon signal comprises measuring signal parameters selected from the group consisting of a received signal strength indicator and a phase delay.
17. An assisted global positioning system (AGPS) for tracking a movable object of interest; said system comprising:
a. a plurality of beacons, each adapted to transmit a respective ID signal identifying said beacon;
b. at least one ground base station that emits retrievable scheduled signals; and
c. at least one GPS-based smart tag releasably affixed to said movable object, said smart tag interconnected to the ground base station and a plurality of GPS satellites by means of one or more communication links, wherein the plurality of GPS satellites emit retrievable scheduled signals, and said smart tag is configured to:
(1) remain in a cold standby condition prior to receiving the ID signal of a nearest one of said beacons,
(2) wake up upon receiving the ID signal from the nearest beacon,
(3) calculate a set of pseudo ranges and transmit the set of pseudo-ranges from said smart tag via the ground base station to a service center, the service center adapted to provide said smart tag with an assisted data, and
(4) be restored to a cold standby condition after transmitting the set of pseudo-ranges;
wherein said service center is adapted to communicate with said tag and receiving the set of pseudo-ranges, and calculating a location of the tag by triangulation of the time delays of said signals received from said satellites.
18. An assisted global positioning system (AGPS) for tracking a movable object of interest; said system comprising:
a. a plurality of beacons, each adapted to transmit a respective ID signal identifying said beacon;
b. at least one ground base station that emits retrievable scheduled signals; and
c. at least one GPS-based smart tag releasably affixed to said movable object, said smart tag interconnected to the ground base station and a plurality of GPS satellites by means of one or more communication links, wherein the plurality of GPS satellites emit retrievable scheduled signals, and said smart tag is configured to:
(1) remain in a cold standby condition prior to receiving the ID signal of a nearest one of said beacons,
(2) wake up upon receiving the ID signal from the nearest beacon,
(3) calculate a set of pseudo ranges and transmit the set of pseudo-ranges from said smart tag via the ground base station, and
(4) be restored to a cold standby condition after transmitting the set of pseudo-ranges; and
d. a service center configured to receive the pseudo ranges calculated by the tag via the ground base station, the service center adapted to provide said smart tag with an assisted data wherein said service center is adapted to communicate with said tag and receiving the set of pseudo-ranges, and calculating a location of the tag by triangulation of the time delays of said signals received from said satellites.