Navigation with satellite communications

• US 7,586,438 B1
• Filed: 04/18/2005
• Issued: 09/08/2009
• Est. Priority Date: 04/19/2004
• Status: Active Grant

• Current Assignee: Novariant Incorporated (Kubota Corporation)
• Original Assignee: Novariant Incorporated (Kubota Corporation)
• Inventors: Lawrence, David G., O'Connor, Michael L.
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): LIU, HARRY K
• Application Number:
  US11/108,195
• Time in Patent Office: 1,604 Days
• Field of Search: 701/120, 701/207, 342/357
• US Class Current: 342/357.4
• CPC Class Codes: G01S 19/074 providing integrity data, e.g. WAAS
• CPC Class Codes: G01S 5/009 Transmission of differential positioning data to mobile

Abstract

A Low Earth Orbiting (LEO) satellite is used for broadcasting differential navigation corrections. Using LEO satellites, the “footprint” of the beam is much smaller than for geosynchronous satellites. Datalink bandwidth requirements are reduced to sufficiently cover an entire footprint area. With a LEO satellite transmitting in multiple beams, these footprints become even smaller. Corrections targeted to such a small area provide local area corrections broadcast from the LEO satellites. Payment, discounts, subsidies or charges are arranged to encourage different entities to own or host base stations, resulting in wide distribution of the network of base stations for use with satellite communications.

Claims

1. A system for communicating position information, the system comprising:

a plurality of reference stations operable to make navigation measurements, cycle ambiguities associated with multiple ones of the reference stations of the network; and

one or more low earth orbit satellites operable to broadcast data responsive to the navigation measurements to multiple receivers;

wherein the reference stations are operable to transmit the navigation measurements directly to the one or more satellites, and wherein the one or more satellites are operable to rebroadcast the navigation measurements on one or more beams.

2. The system of claim 1 wherein a centralized processing facility is operable to receive the broadcast navigation measurements, the centralized processing facility being operable to generate model information as a function of the navigation measurements, and the centralized processing facility operable to transmit the model information to the one or more satellites.

3. The system of claim 2 wherein the navigation measurements comprise differential corrections, model corrections or both differential and model corrections.

4. The system of claim 2 wherein the model information comprises model information for a weather model, an atmosphere model, an orbital model or a combination thereof.

5. The system of claim 2 wherein the one or more satellites are operable to rebroadcast the navigation measurements in real-time and wherein the centralized processing facility is operable to transmit the model information after a delay.

6. The system of claim 2 wherein, at a given time, some reference stations transmit differential corrections directly to the one or more low earth orbit satellites and others of the reference stations transmit navigation measurements to the centralized processing facility through the one or more satellites, the navigation measurements being the differential corrections or model information.

7. The system of claim 2 wherein the receivers are operable to receive the navigation measurements from one or more satellites, the receivers each operable to determine a location with the navigation measurements from the one or more satellites and navigation signals from the one or more navigation satellites.

8. The system of claim 1 wherein the reference stations analyze the navigation measurements of other reference stations.

9. The system of claim 1 further comprising a user receiver operable to receive at least some of the navigation measurements terrestrially from at least one of the reference stations.

10. The system of claim 1 wherein the reference stations are operable to determine an error and distinguish between an environmental error and reference station movement error.

11. The system of claim 1 wherein the reference stations comprise multiple antennas.

12. The system of claim 1 wherein the reference stations are operable to receive the navigation measurements of other ones of the reference stations and only transmit non-redundant corrections.

13. The system of claim 1 further comprising a dual band user receiver.

14. The system of claim 1 wherein the reference stations are operable to transmit carrier phase information.

15. The system of claim 1 wherein the reference stations are operable to transmit the navigation measurements terrestrially.

16. A system for communicating position information, the system comprising:

a plurality of reference stations each operable to make navigation measurements, cycle ambiguities associated with multiple ones of the reference stations of the network; and

multiple low earth orbit satellites operable to broadcast data responsive to the navigation measurements to multiple receivers;

wherein the reference stations are each operable to analyze the navigation measurements of other reference stations and to transmit the navigation measurements directly to the one or more satellites having a beam footprint over the reference station at the time of transmission such that different reference stations communicate with different ones of the low earth orbit satellites at a given time and such that less than all of the navigation measurements are transmitted by the reference stations to the low earth orbit satellites;

wherein the one or more satellites are operable to rebroadcast the navigation measurements on one or more beams, each satellite rebroadcasting the navigation measurements responsive to a sub-set of the reference stations at a given time, the sub-set being reference stations within or adjacent to the beam footprint of the one or more beams of each satellite; and

wherein the navigation measurements are dynamically distributed between different satellites so that navigation measurements appropriate for a given region are transmitted to that region and the navigation measurements broadcast by each of the satellites varies as a function of the location of the beam footprint.

17. The system of claim 16 wherein the reference stations are operable to determine an error and distinguish between an environmental error and reference station movement error.

18. The system of claim 16 wherein the reference stations are operable to receive the navigation measurements of other ones of the reference stations and only transmit non-redundant corrections.