Method and apparatus for maintaining integrity of long-term orbits in a remote receiver

Abstract

A method and apparatus for maintaining integrity of long-term-orbit information used by a Global-Navigation-Satellite-System or other positioning receiver is described. The method comprises obtaining a predicted pseudorange from a first set of long-term-orbit information possessed by a positioning receiver; obtaining, at the positioning receiver from at least one satellite, a measured pseudorange; determining validity of the predicted pseudorange as a function of the predicted pseudorange and the measured pseudorange; and excluding from the long-term-orbit information at least a portion thereof when the validity of the predicted pseudorange is deemed invalid. Optionally, the method may comprise updating or otherwise supplementing the long-term-orbit information with other orbit information if the validity of the predicted pseudorange is deemed invalid.

1 . A method, comprising:
 obtaining a predicted pseudorange from long-term-orbit information possessed by a first receiver;   obtaining, at a second receiver from at least one satellite, a measured pseudorange;   determining validity of the predicted pseudorange as a function of the predicted pseudorange and the measured pseudorange; and   excluding from the long-term orbit information at least a portion of thereof when the validity of the predicted pseudorange is deemed invalid.   
     
     
         2 . The method of  claim 1 , wherein excluding at least a portion of the long-term orbit information comprises:
 discarding long-term orbit information associated with the at least one satellite from which the measured pseudorange is obtained.   
     
     
         3 . The method of  claim 1 , wherein determining validity of the predicted pseudorange comprises:
 determining a difference between the predicted pseudorange and the measured pseudorange, and wherein excluding at least a portion of the long-term-orbit information occurs when the difference satisfies a given threshold.   
     
     
         4 . The method of  claim 1 , further comprising:
 performing the functions of  claim 1  periodically.   
     
     
         5 . The method of  claim 1 , further comprising:
 supplementing the long-term-orbit information when the validity of the predicted pseudorange is deemed invalid.   
     
     
         6 . The method of  claim 5 , wherein supplementing the long-term-orbit information comprises supplementing the long-term-orbit information with information selected from the group consisting of broadcast ephemeris, and long-term-orbit information. 
     
     
         7 . The method of  claim 5 , wherein supplementing the long-term-orbit information comprises:
 discarding the long-term-orbit information in lieu of broadcast ephemeris.   
     
     
         8 . The method of  claim 5 , wherein determining validity of the predicted pseudorange comprises:
 determining a difference between the predicted pseudorange and the measured pseudorange, and wherein supplementing the long-term-orbit information occurs when the difference satisfies a given threshold.   
     
     
         9 . The method of  claim 5 , further comprising:
 sending from the first receiver a request for supplemental orbit information when the validity of the predicted pseudorange is deemed invalid; and   receiving at the first receiver, in response to the request, the supplemental orbit information.   
     
     
         10 . The method of  claim 9 , wherein the supplemental orbit information is more current than the long-term-orbit information. 
     
     
         11 . The method of  claim 5 , wherein supplementing the long-term-orbit information comprises supplementing the long-term-orbit information with broadcast ephemeris obtained from the at least one satellite. 
     
     
         12 . The method of  claim 5 , wherein supplementing the long-term-orbit information comprises:
 replacing all of the long-term-orbit information.   
     
     
         13 . The method of  claim 1 , wherein the first receiver is a remote receiver, and wherein the second receiver is a reference receiver. 
     
     
         14 . The method of  claim 1 , wherein the first and second receivers are the same receiver. 
     
     
         15 . The method of  claim 14 , wherein the same receiver is a remote receiver. 
     
     
         16 . A method, comprising:
 (a) using long-term-orbit information to determine, at a receiver, a first position of the receiver, wherein the first position comprises at least one first location parameter;   (b) using satellite-navigation data transmitted from at least one satellite to determine, at the receiver, a second position of the receiver, wherein the second position comprises at least one second location parameter;   (c) determining a difference between (i) the at least one first location parameter and (ii) the at least one second location parameter; and   (d) confirming that the long-term-orbit information is valid when the difference satisfies a given threshold.   
     
     
         17 . The method of  claim 16 , wherein the at least one first location parameter comprises a first parameter and a second parameter, wherein the at least one second location parameter comprises a third parameter and a fourth parameter;
 wherein the difference comprises a first difference and a second difference;   wherein the first difference comprises a difference between the first and third parameters, wherein the second difference comprises a difference between the second and fourth parameters, and wherein confirming that the long-term-orbit information is valid comprises confirming that the first and second differences satisfy respective thresholds.   
     
     
         18 . The method of  claim 17 , wherein the first parameter is a first altitude and the second parameter is any of first longitude and first latitude, and wherein the third parameter is a second altitude and the second parameter is any of a second longitude and second latitude. 
     
     
         19 . The method of  claim 16 , further comprising:
 performing (c) and (d) responsive to a deviation between the first and second positions.   
     
     
         20 . The method of  claim 16 , wherein the at least one first location parameter comprises any of a first longitude, first latitude, first altitude and first common-mode error obtained from the long-term-orbit information, and wherein the at least one second location parameter comprises any of a second longitude, second latitude, second altitude and second common-mode error obtained from the satellite-navigation data transmitted from at least one satellite. 
     
     
         21 . The method of  claim 20 , wherein the at least one first location parameter comprises a plurality of first locations parameters, wherein the at least one second location parameter comprises a plurality of second location parameters, and further comprising:
 performing (c) and (d) using each of the pluralities of first and second location parameters.   
     
     
         22 . The method of  claim 16 , further comprising:
 excluding from the long-term orbit information at least a portion of the long-term orbit information when the long-term orbit information is deemed invalid;   obtaining supplemental orbit information from a device remotely located from the receiver; and   supplementing the long-term-orbit information with the supplemental orbit information when the validity of the predicted pseudorange is deemed invalid.   
     
     
         23 . The method of  claim 22 , wherein the supplemental orbit information comprises information selected from the group consisting of broadcast ephemeris, and long-term-orbit information. 
     
     
         24 . The method of  claim 22 , wherein supplementing the long-term-orbit information with the supplemental orbit information comprises:
 replacing the long-term-orbit information with the supplemental orbit information.   
     
     
         25 . The method of  claim 24 , further comprising:
 sending from the receiver a request for the supplemental orbit information when the difference between satisfies the given threshold; and   receiving at the satellite-signal receiver, in response to the request, the supplemental orbit information.   
     
     
         26 . (canceled) 
     
     
         27 . A receiver comprising:
 memory operable to store executable instructions and long-term-orbit information;   a processor operable to obtain from the memory the executable instructions and operable to execute the executable instructions to:   obtain a predicted pseudorange from the long-term-orbit information;   obtain a measured pseudorange from at least one satellite;   determine validity of the predicted pseudorange as a function of the predicted pseudorange and the measured pseudorange; and   exclude from the long-term-orbit information at least a portion thereof when deeming the validity of the predicted pseudorange is deemed invalid.   
     
     
         28 . The receiver of  claim 27 , wherein the executable instructions to exclude at least a portion of the long-term orbit information comprises:
 executable instructions to discard long-term orbit information associated with the at least one satellite from which the measured pseudorange is obtained.   
     
     
         29 . The receiver of  claim 27 , further comprising:
 executable instructions to supplement the long-term-orbit information with supplemental orbit information when the validity of the predicted pseudorange is deemed invalid.   
     
     
         30 . The receiver of  claim 29 , wherein the supplemental orbit information comprises information selected from the group consisting of broadcast ephemeris, and long-term-orbit information. 
     
     
         31 . The receiver of  claim 29 , wherein executable instructions to supplement the long-term-orbit information comprise:
 executable instructions to discard the long-term-orbit information in lieu of broadcast ephemeris.   
     
     
         32 . The receiver of  claim 27 , wherein the executable instructions to determine validity of the predicted pseudorange comprises executable instructions to determine a difference between the predicted pseudorange and the measured pseudorange, and wherein the processor is operable to execute the executable instructions to exclude at least a portion of the long-term-orbit information when the difference satisfies a given threshold. 
     
     
         33 . The receiver of  claim 29 , further comprising:
 a transceiver for sending from the receiver a request for the supplemental orbit information when the validity of the predicted pseudorange is deemed invalid; and   for receiving at the receiver, in response to the request, the supplemental orbit information.   
     
     
         34 . A system comprising:
 a receiver comprising:   a first memory operable to store executable instructions and long-term-orbit information; and   a first processor operable to obtain from the first memory the executable instructions and operable to execute the executable instructions to:   use long-term-orbit information to determine, at the receiver, a first position of the receiver, wherein the first position comprises at least one first location parameter;   use satellite-navigation data transmitted from at least one satellite to determine, at the receiver, a second position of the receiver, wherein the second position comprises at least one second location parameter;   determine a difference between (i) the at least one first location parameter and (ii) the at least one second location parameter; and   confirm that the long-term-orbit information is valid when the difference satisfies a given threshold; and   a server comprising:   a second memory operable to store executable instructions, the long-term-orbit information and supplemental orbit information; and   a second processor operable to obtain from the second memory the executable instructions and operable to execute the executable instructions to:   provide to the receiver the long-term-orbit information; and   provide to the receiver the supplemental orbit information.   
     
     
         35 . The system of  claim 34 , wherein the first processor is further operable to execute the executable instructions to:
 exclude from the long-term orbit information at least a portion of thereof when the long-term orbit information is deemed invalid; and   supplement the long-term-orbit information with the supplemental orbit information when the validity of the predicted pseudorange is deemed invalid.   
     
     
         36 . The system of  claim 34 , wherein the supplemental orbit information comprises information selected from the group consisting of broadcast ephemeris, and long-term-orbit information. 
     
     
         37 . The system of  claim 36 , wherein the executable instructions to supplement the long-term-orbit information with the supplemental orbit information comprise:
 executable instructions to replace the long-term-orbit information with the supplemental orbit information.   
     
     
         38 . The system of  claim 35 , wherein the first parameter is a first altitude and the second parameter is any of first longitude and first latitude, and wherein the third parameter is a second altitude and the second parameter is any of a second longitude and second latitude. 
     
     
         39 . The system of  claim 35 , wherein the first processor is further operable to execute the executable instructions to determine the difference and to confirm that the long-term-orbit information is valid responsive to a deviation between the first and second positions. 
     
     
         40 . The system of  claim 35 , wherein the first processor is further operable to execute the executable instructions to supplement the at least one first location parameter with a third location parameter obtained from the orbit information when the difference satisfies a given threshold. 
     
     
         41 . A system comprising:
 a receiver comprising:   a first memory operable to store executable instructions and a first set of long-term-orbit information; and   a first processor operable to obtain from the first memory the executable instructions and operable to execute the executable instructions to:   use the first set of long-term-orbit information to determine, at the receiver, a first position of the receiver, wherein the first position comprises at least one first location parameter;   use satellite-navigation data transmitted from at least one satellite to determine, at the receiver, a second position of the receiver, wherein the second position comprises at least one second location parameter; and   a server comprising:   a second memory operable to store executable instructions, the long-term-orbit information and first and second sets of long-term-other orbit information; and   a second processor operable to obtain from the second memory the executable instructions and operable to execute the executable instructions to:   provide to the receiver the first set of set of long-term-orbit information;   determine a difference between (i) the at least one first location parameter and (ii) the at least one second location parameter;   confirm that the first set of long-term-orbit information is valid when the difference satisfies a given threshold; and   provide to the receiver the second set of long-term-other orbit information.   
     
     
         42 . A system comprising:
 a first receiver comprising:   a first memory operable to store executable instructions and long-term-orbit information; and   a first processor operable to obtain from the first memory the executable instructions and operable to execute the executable instructions to:   obtain a predicted pseudorange from the long-term-orbit information possessed by the first receiver;   a second satellite-signal receiver comprising:   a second memory operable to store executable instructions; and   a second processor operable to obtain from the second memory the executable instructions and operable to execute the executable instructions to:   obtain, from at least one satellite, a measured pseudorange;   a server comprising:   a third memory operable to store executable instructions, the long-term-orbit information and other orbit information; and   a third processor operable to obtain from the third memory the executable instructions and operable to execute the executable instructions to:   determine validity of the predicted pseudorange as a function of the predicted pseudorange and the measured pseudorange; and   send to the first receiver the other orbit information when the validity of the predicted pseudorange is deemed invalid.   
     
     
         43 . The system of  claim 42 , wherein the executable instructions to determine validity of the predicted pseudorange comprise:
 executable instructions to determine a difference between the predicted pseudorange and the measured pseudorange, and wherein the executable instructions to send to the first receiver the second set of long-term-other orbit information occurs when the difference satisfies a given threshold.   
     
     
         44 . The system of  claim 42 , wherein the first receiver is a remote receiver, and wherein the second receiver is a reference receiver. 
     
     
         45 . The system of  claim 42 , wherein the first and second receivers are the same receiver and wherein the first memory and the second memory are the different. 
     
     
         46 . The system of  claim 45 , wherein the same receiver is a remote receiver. 
     
     
         47 . The method of  claim 1 , wherein the long-term-orbit information has a validity period exceeding four hours.