Method and apparatus for satellite positioning system (SPS) time measurement
DCFirst Claim
1. A method for measuring time related to satellite data messages for use with a satellite positioning system (SPS), said method comprising:
- receiving at an entity a first record of at least a portion of a satellite data message of a satellite positioning system;
comparing said first record with a second record of said satellite data message wherein said first record and said second record overlap at least partially in time, said comparing being performed after determining an estimated time when said first record was received;
determining a time from said comparing, said time indicating when said first record was received at a remote entity.
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Abstract
A method and apparatus for measuring time related to satellite data messages which are used with satellite positioning systems (SPS). In one method, a first record of at least a portion of a satellite data message is received at an entity, which is typically a basestation. The first record is compared with a second record of the satellite data message, where the first record and the second record overlap at least partially in time. Then a time is determined from this comparison, and this time indicates when the first record (or the source from which the first record was obtained) was received at a remote entity which is typically a mobile SPS receiver. Various other methods of the invention are described and various apparatuses of the invention are also described. The methods and apparatuses measure time of day using SPS signals without reading the satellite data messages which are transmitted as data within these signals. The methods and apparatuses are suitable for situations in which the received signal level is too weak to allow reading of the satellite data messages.
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Citations
88 Claims
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1. A method for measuring time related to satellite data messages for use with a satellite positioning system (SPS), said method comprising:
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receiving at an entity a first record of at least a portion of a satellite data message of a satellite positioning system;
comparing said first record with a second record of said satellite data message wherein said first record and said second record overlap at least partially in time, said comparing being performed after determining an estimated time when said first record was received;
determining a time from said comparing, said time indicating when said first record was received at a remote entity. - View Dependent Claims (2, 3, 4)
determining a comparison range from said estimated time when said first record was received.
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4. A method as in claim 1 wherein said second record provides time of day information such that said time may be determined from said second record.
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5. A method for measuring time related to satellite data messages for use with a satellite positioning system, said method comprising:
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receiving at an entity a first record of at least a portion of a satellite data message of a satellite positioning system;
determining a comparison range from an estimated time when said first record was received;
comparing said first record with a second record of said satellite data message wherein said first record and said second record overlap at least partially in time and wherein said comparing is performed at least in a portion of said comparison range;
determining a time from said comparing, said time indicating when said first record was received at a remote entity. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
using said time and said plurality of pseudoranges to determine a position information of said remote entity.
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14. A method as in claim 9 wherein said first record comprises 50 baud data.
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15. A method as in claim 7 further comprising precisely determining a carrier frequency of said first record.
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16. A method as in claim 7 wherein said determining of said comparison range comprises transmitting at least one message between said entity and said remote entity.
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17. A method as in claim 16 wherein said transmitting comprises transmitting a first message from said entity to said remote entity and transmitting a second message from said remote entity to said entity.
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18. A method as in claim 17 wherein said first record comprises at least one record of at least said portion of said satellite data message corresponding to a first pseudorange of a plurality of pseudoranges.
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19. A method as in claim 18 further comprising:
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receiving at said entity a third record of at least a portion of a second satellite data message;
comparing said third record with a fourth record of said second satellite data message, wherein said third record and said fourth record overlap at least partially in time;
determining a second time from said comparing step, said second time indicating when said third record was received at said remote entity, wherein said second satellite data message corresponds to a second pseudorange of said plurality of pseudoranges.
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20. A method as in claim 7 wherein said remote entity comprises a cellular telephone and said first record is received from said cellular telephone through a cellular telephone site.
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21. An apparatus for measuring time related to satellite data messages for use with a satellite positioning system, said apparatus comprising:
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a receiver for receiving a first record of at least a portion of a satellite data message;
a data processor coupled to said receiver, said data processor performing a comparison in a comparison range of said first record with a second record of said satellite data message wherein said first record and said second record overlap at least partially in time and determining a time from said comparison, said time indicating when said first record was received at a remote entity wherein said comparison range is determined from an estimated time when said first record was received at said remote entity. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A method for measuring time related to satellite data messages for use with a satellite positioning system (SPS), said method comprising:
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receiving in a mobile SPS receiver at least a portion of a satellite data message;
determining a first record of said at least a portion of said satellite data message;
determining a parameter which specifies a comparison range from an estimated time when said first record was received at said mobile SPS receiver;
transmitting said first record to a remote basestation for the purpose of determining a time indicating when said first record was received at said mobile SPS receiver. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43)
receiving GPS signals and determining a plurality of pseudoranges;
transmitting said plurality of pseudoranges.
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40. A method as in claim 39 wherein said first record comprises 50 baud data.
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41. A method as in claim 36 further comprising removing a carrier frequency from said GPS signals.
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42. A method as in claim 41 further comprising differentially detecting said first record.
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43. A method as in claim 35 wherein said determining said parameter which specifies said comparison range comprises one of transmitting a first message from said mobile SPS receiver to said remote basestation or receiving a second message from said remote basestation.
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44. A satellite positioning system (SPS) receiver comprising:
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an antenna for receiving SPS signals;
a demodulator coupled to said antenna, said demodulator removing a PN code from said SPS signals;
a processor coupled to said demodulator, said processor determining a first record of at least a portion of a satellite data message received from said demodulator and determining a parameter which specifies a comparison range from an estimated time when said first record was received at said SPS receiver;
a transmitter coupled to said processor, said transmitter transmitting said first record to a remote basestation. - View Dependent Claims (45, 46, 47)
a communication antenna coupled to said transmitter, said communication antenna for transmitting said first record to said remote basestation.
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46. A receiver as in claim 44 further comprising:
a correlator coupled to said antenna, said correlator acquiring said SPS signals and determining at least one pseudorange.
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47. A receiver as in claim 44 wherein said determining of said parameter comprises one of transmitting a first message from said SPS receiver to said remote basestation or receiving a second message from said remote basestation.
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48. A satellite positioning system (SPS) receiver comprising:
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a SPS antenna for receiving SPS signals;
a processor coupled to said SPS antenna, said processor processing said SPS signals and determining at least one pseudorange from said SPS signals, said processor removing a PN code from said SPS signals to provide a first record of at least a portion of a satellite data message in said SPS signals and determining at least one parameter which specifies a comparison range from an estimated time when said first record was received at said SPS receiver;
a transmitter coupled to said digital processor, said transmitter transmitting said first record to a remote basestation. - View Dependent Claims (49)
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50. In a mobile satellite positioning system (SPS) receiver, a method for measuring time related to satellite data messages with use with an SPS, said method comprising:
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receiving at said mobile SPS receiver a first record of at least a portion of a satellite data message;
receiving at said mobile SPS receiver a second record of said satellite data message, wherein said first record and said second record overlap at least partially in time;
determining a comparison range;
comparing said first record with said second record at least in said comparison range determined from an estimated time when said first record was received at said mobile SPS receiver;
determining a time from said comparing, said time indicating when said first record was received at said mobile SPS receiver. - View Dependent Claims (51, 52, 53, 54, 55, 56)
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57. A mobile satellite positioning system (SPS) receiver comprising:
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an antenna for receiving SPS signals;
a demodulator coupled to said antenna, said demodulator removing a PN code from said SPS;
a processor coupled to said demodulator, said processor determining a first record of at least a portion of a satellite data message received from said demodulator and determining a comparison range;
a communication antenna;
a communication receiver coupled to said communication antenna and to said processor, said communication receiver receiving a second record of said satellite data message, wherein said first record and said second record overlap at least partially in time, said processor comparing said first record and said second record at least in said comparison range determined from an estimated time when said first record was received at said mobile SPS receiver and determining a time indicating when said first record was received. - View Dependent Claims (58, 59, 60, 61, 62)
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63. An apparatus for assisting in the measurement of time related to satellite data messages for use with a satellite positioning system (SPS), said apparatus comprising:
a transmitter which is for transmitting a second record of a satellite data message for use in comparing to a first record of at least a portion of a satellite data message, said transmitter transmitting a message which is used to determine a comparison range for comparing said first record to said second record, said comparison range being based on an estimated time when said first record was received at a remote mobile SPS receiver.
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64. A method for measuring time related to satellite data messages for use with a satellite positioning system (SPS), said method comprising:
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receiving at an entity a first record of at least a portion of a satellite data message of a satellite positioning system;
comparing said first record with a second record of said satellite data message, said comparing being performed after determining an estimated time when said first record was received;
determining a time from said comparing, said time indicating when said first record was received at a remote entity. - View Dependent Claims (65, 66, 67)
determining a comparison range from said estimated time when said first record was received.
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67. A method as in claim 64 wherein said second record provides time of day information such that said time may be determined from said second record.
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68. An apparatus for measuring time related to satellite data messages for use with a satellite positioning system, said apparatus comprising:
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a receiver for receiving a first record of at least a portion of a satellite data message;
a data processor coupled to said receiver, said data processor performing a comparison in a comparison range of said first record with a second record of said satellite data message and determining a time from said comparison, said time indicating when said first record was received at a remote entity wherein said comparison range is determined from an estimated time when said first record was received at said remote entity. - View Dependent Claims (69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81)
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82. In a mobile satellite positioning system (SPS) receiver, a method for measuring time related to satellite data messages for use with an SPS, said method comprising:
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receiving at said mobile SPS receiver a first record of at least a portion of a satellite data message;
receiving at said mobile SPS receiver a second record of said satellite data message;
determining a comparison range;
comparing said first record with said second record at least in said comparison range determined from an estimated time when said first record was received at said mobile SPS receiver;
determining a time from said comparing, said time indicating when said first record was received at said mobile SPS receiver. - View Dependent Claims (83, 84, 85, 86, 87, 88)
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Specification