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 with other orbit information when the validity of the predicted pseudorange is deemed invalid.  
     
     
         6 . The method of  claim 5 , wherein the other orbit information comprises 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 with 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 with other 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 the other orbit information when the validity of the predicted pseudorange is deemed invalid; and    receiving at the first receiver, in response to the request, the other orbit information.    
     
     
         10 . The method of  claim 3 , wherein the other orbit information is more current than the long-term-orbit information.  
     
     
         11 . The method of  claim 5 , wherein the other orbit information comprises broadcast ephemeris obtained from the at least one satellite.  
     
     
         12 . The method of  claim 5 , wherein supplementing the long-term-orbit information with the other orbit information comprises: replacing all of the long-term-orbit information with other 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 thereof when the long-term orbit information is deemed invalid;    obtaining other orbit information from a device remotely located from the receiver; and    supplementing the long-term-orbit information with the other orbit information when the validity of the predicted pseudorange is deemed invalid.    
     
     
         23 . The method of  claim 22 , wherein the other 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 other orbit information comprises: replacing the long-term-orbit information with the other orbit information.  
     
     
         25 . The method of  claim 24 , further comprising: 
 sending from the receiver a request for the other orbit information when the difference between satisfies the given threshold; and    receiving at the satellite-signal receiver, in response to the request, the other orbit information.    
     
     
         26 . The method of  claim 22 , wherein supplementing the long-term-orbit information with the other orbit information comprises: replacing the at least one first location parameter with a third location parameter obtained from the other orbit information when the difference satisfies a given threshold.  
     
     
         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 other orbit information when the validity of the predicted pseudorange is deemed invalid.  
     
     
         30 . The receiver of  claim 29 , wherein the other 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 27 , further comprising: a transceiver for sending from the receiver a request for the other orbit information when the validity of the predicted pseudorange is deemed invalid; and for receiving at the receiver, in response to the request, the other 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 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 long-term-orbit information; and  
 provide to the receiver the other orbit information.  
 
   
     
     
         35 . The system of  claim 35 , 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 other orbit information when the validity of the predicted pseudorange is deemed invalid.    
     
     
         36 . The system of  claim 36 , wherein the other 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 other orbit information comprise: executable instructions to replace the long-term-orbit information with the other 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.  
     
     
         46 . The system of  claim 45 , wherein the same receiver is a remote receiver.