Mobile GPS aiding data solution

• US 7,495,609 B1
• Filed: 11/07/2006
• Issued: 02/24/2009
• Est. Priority Date: 11/07/2006
• Status: Expired due to Fees

• Current Assignee: Furuno Electric Co, Ltd
• Original Assignee: eRide, Inc. (Furuno Electric Co, Ltd)
• Inventors: Zeisel, Guenter, Woo, Arthur N.
• Primary Examiner(s): PHAN, DAO LINDA
• Application Number:
  US11/594,521
• Time in Patent Office: 840 Days
• Field of Search: 342/357.01, 342/357.06, 342/357.09, 342/357.12, 342/357.13, 701/213, 701/215
• US Class Current: 342/357.64
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/25 involving aiding data received from a cooperating element, e.g. assisted GPS

Abstract

A mobile GPS-aiding system uses a GPS reference receiver to collect GPS navigation messages, a GPS-aiding data network server to distribute over the Internet all ephemeris and almanac data gleaned from the navigation messages, a number of commercial broadcast radio stations to publish such ephemeris and almanac data on particular sub-carriers, a number of vehicles equipped to receive the radio broadcasts and the sub-carriers and to retransmit them locally, e.g., via Bluetooth. Portable GPS receivers, operated near any of the vehicles, a receive Bluetooth transmissions with the ephemeris and almanac data with the identity of the radio broadcast station then being tuned. A breadcrumb database is used to index the locations of the radio broadcast stations. Each mobile GPS receiver contributes to such database after it computes a location fix. If the location of the radio broadcast station is already known to the database, then the location can be accessed and used before finding a position solution.

Claims

1. A mobile GPS-aiding system, comprising:

a GPS reference receiver to collect GPS navigation messages;

a GPS-aiding data network server to distribute over the Internet ephemeris and almanac data gleaned from said navigation messages;

a number of commercial broadcast radio stations to publish such ephemeris and almanac data on particular sub-carriers;

a number of vehicles equipped to receive radio broadcasts and said sub-carriers and to retransmit them locally via Bluetooth;

at least one mobile, portable GPS receiver, for operation near any of the vehicles, and able to receive Bluetooth transmissions with the ephemeris and almanac data, together with the identity of the radio broadcast station then being tuned; and

a breadcrumb database to index the locations of the radio broadcast stations.

2. The mobile GPS-aiding system of claim 1, wherein each mobile, portable GPS receiver may contribute to the breadcrumb database after a location fix is computed.

3. The mobile GPS-aiding system of claim 1, wherein if the location of a particular radio broadcast station is already known to the breadcrumb database, then the location is accessed and used to get a head-start on finding a position solution by the mobile, portable GPS receiver.

4. A mobile GPS-aiding system vehicle, comprising:

at least one of an automobile, truck, motorcycle, trailer, bus, train, airplane, ship, barge, trolley, or other mobile vehicular transport;

a broadcast radio receiver carried aboard the mobile transport to receive commercial radio broadcasts with sub-carriers modulated with GPS aiding information obtained from a GPS reference receiver;

a piconet connected to the broadcast radio receiver and providing for a local retransmission of said GPS aiding information via Bluetooth wireless links;

wherein, the locations of any transmitters tuned by the broadcast radio receiver are logged into a breadcrumb database for inclusion in said GPS aiding information.

5. The vehicle of claim 4, further comprising a subscription to a service provider having:

a GPS reference receiver to collect GPS navigation messages;

a GPS-aiding data network server to distribute over the Internet ephemeris and almanac data gleaned from said navigation messages;

subscribers including a number of commercial broadcast radio stations to publish such ephemeris and almanac data on particular sub-carriers;

end-users including at least one mobile, portable GPS receiver, for operation near any of the vehicles, and able to receive Bluetooth transmissions with the ephemeris and almanac data, together with the identity of the radio broadcast station then being tuned; and

a breadcrumb database to index the locations of the radio broadcast stations.

6. A subscription service, comprising:

a GPS reference receiver to collect GPS navigation messages directly from orbiting GPS navigation satellites;

a GPS-aiding data network server to distribute over the Internet GPS system ephemeris and almanac data interpreted from said navigation messages;

subscribers including a number of commercial broadcast radio stations to publish such ephemeris and almanac data on particular sub-carriers;

end-users including at least one mobile, portable GPS receiver, for operation near any of the vehicles, and able to receive Bluetooth transmissions with the ephemeris and almanac data, together with the identity of the radio broadcast station then being tuned; and

a breadcrumb database to index the locations of the radio broadcast stations.

7. A portable client, comprising:

a piconet transceiver for obtaining GPS aiding information and breadcrumb information relayed from a network server and a GPS reference station over a broadcast radio receiver and a piconet server within range of their included Bluetooth wireless links; and

a navigation receiver for computing and outputting fully autonomous position solutions from pseudorange signals it receives directly from orbiting navigation satellites and that are assisted initially by said GPS aiding information and breadcrumb information provided by the piconet transceiver;

wherein, a position solution for a nearby landmark is earlier associated in a database of said breadcrumb information with an ID code as an index that will provide an initial position estimate of the navigation receiver when operating within said a corresponding service area of said broadcast radio receiver.

8. A navigation satellite receiver system, comprising:

a portable client comprising a navigation receiver and a piconet transceiver;

a piconet server mounted to a vehicle and accessible to the portable client by a wireless connection in a local area supported by the piconet transceiver; and

a breadcrumb database associated with an Internet server in communication with the vehicle via commercial radio broadcasts, and that accumulates and distributes positions corresponding to the commercial broadcast transmitter locations according to an identifier (ID) recognizable to the portable client.

9. The system of claim 8, wherein:

the portable client includes a device to fetch a position from the breadcrumb database to improve its ability to obtain a position solution.

10. The system of claim 8, wherein:

the portable client includes a device to contribute a position to the breadcrumb database for later visitors to the same commercial broadcast service area to improve their ability to obtain a position solution.

11. The system of claim 8, wherein:

the portable client includes a device to select a landmark name from the breadcrumb database and then receive a position from the database to improve its ability to obtain a position solution.

12. The system of claim 8, wherein the portable client includes a navigation receiver process for extending its fix range under weak signal conditions, comprising:

a device for receiving a GPS navigation message that has data bit wavelength and a half cycle ambiguity;

a device for accepting parity errors in said NAVdata GPS navigation message that otherwise prevent its decoding;

a device for extracting a data bit phase from said NAVdata message;

a device for estimating the number of data bits N_set by equating a predicted range to a measured range when a time-stamp is not available, but a measured bit transition time (BTT_m) and codephase are available; and

a device for outputting a position solution.

13. The system of claim 12, wherein:

the device for receiving depends on the locally generated frequency to be within half of the GPS navigation message bit rate of the true frequency in order to observe GPS navigation message data-bit phase reversals.

14. The system of claim 13, further comprising:

a device for using a high sensitivity code and frequency tracking loop driven by a strongest signal from a search window with a multitude of codephase and frequencies hypotheses from long non-coherent integrations times, and such that the frequency spacing between hypotheses is small enough to reduce the frequency error, and the inputs to a bit transition time (BTT) estimator are the consecutive in-phase and quadrature correlation results at the code and frequency loop state.

15. The system of claim 12, wherein:

the device for receiving is such that histogram with several elements is used to integrate counts of events when the dot product at a given bit transition time (BTT) hypothesis is negative, and the BTT is declared found when the histogram count at a particular BTT hypothesis reaches a confidence value above the other candidates.

16. The system of claim 12, wherein:

the step of device for receiving is such that a bit transition time (BTT) location is converted to GPS time by associating a BTT location with the sum of the codephase plus a GPS-millisecond counter adjacent to an epoch location of a winning BTT histogram.

17. The system of claim 12, wherein:

the device for receiving is such that after a bit transition time (BTT) is determined, the GPS navigation message is demodulated by forming another dot product test statistic at a best hypothesis of a data bit phase.