Determining position of a GNSS receiver using fractional signalling event period times
First Claim
1. An apparatus for calculating a position of the apparatus by using a time for periodic signalling events to travel from a plurality of satellites to the apparatus, the apparatus including:
- a global navigation satellite system (GNSS) receiver configured to receive one of the periodic signalling events from each satellite, respectively;
a processor configured to;
determine, for each of the plurality of satellites, an initial estimate of a transit time for a periodic signalling event to travel from a respective satellite to the GNSS receiver; and
determine, for each of the plurality of satellites, an expected transit time for the periodic signalling event to travel from the respective satellite to the GNSS receiver based on an estimated current position of the GNSS receiver and a predetermined estimate of a position of the respective satellite;
designate one of the plurality of satellites as a reference satellite;
compare the initial estimate of the transit time and the expected transit time for each non-reference satellite with the initial estimate of the transit time and the expected transit time for the reference satellite, respectively, to form respective residuals that are representative of a combined error in the expected transit times; and
calculate the position of the GNSS receiver, without calculating an integer part of the initial estimates of the transit times based on the periodic signalling events, using the residuals.
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Accused Products
Abstract
Apparatus for calculating the position of a receiver in dependence on the time it takes signalling events to travel from a plurality of satellites to the receiver, obtains an indication of a transit time for a signalling event to travel from each satellite to the receiver, and forms an indication of an expected transit time for a signalling event to travel from the satellite to the receiver. The obtained indication of the transit time and the indication of the expected transit time for each non-reference satellite are compared with the obtained indication of the transit time and the indication of the expected transit time for the reference satellite to form residuals that are representative of a combined error in those indications of expected transit time; and the position of the receiver is calculate without calculating the integer ambiguities in the obtained transit times, in dependence on the residuals.
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Citations
46 Claims
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1. An apparatus for calculating a position of the apparatus by using a time for periodic signalling events to travel from a plurality of satellites to the apparatus, the apparatus including:
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a global navigation satellite system (GNSS) receiver configured to receive one of the periodic signalling events from each satellite, respectively; a processor configured to; determine, for each of the plurality of satellites, an initial estimate of a transit time for a periodic signalling event to travel from a respective satellite to the GNSS receiver; and determine, for each of the plurality of satellites, an expected transit time for the periodic signalling event to travel from the respective satellite to the GNSS receiver based on an estimated current position of the GNSS receiver and a predetermined estimate of a position of the respective satellite; designate one of the plurality of satellites as a reference satellite; compare the initial estimate of the transit time and the expected transit time for each non-reference satellite with the initial estimate of the transit time and the expected transit time for the reference satellite, respectively, to form respective residuals that are representative of a combined error in the expected transit times; and calculate the position of the GNSS receiver, without calculating an integer part of the initial estimates of the transit times based on the periodic signalling events, using the residuals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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44. An apparatus configured to determine a position of the apparatus, the apparatus including:
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a global navigation satellite system (GNSS receiver configured to receive respective periodic signalling events from a plurality of satellites; and a processor configured to; perform a comparison between a fractional part of a time-of-arrival at the GNSS receiver of a periodic signalling event transmitted by a first satellite of the plurality of satellites, a fractional part of a time-of-arrival of a periodic signalling event transmitted by a second satellite of the plurality of satellites, and respective estimated distances between the GNSS receiver and the first and second satellites, and calculate the position of the GNSS receiver using a fractional part of a result of that comparison, wherein; the estimated distances between the GNSS receiver and the first and second satellites are determined from respective times-of-arrival of the periodic signalling events transmitted by the first and second satellites, the fractional parts are fractional parts of the period of the signalling events, and the processor does not determine an integer part of the times-of-arrival of the periodic signalling events when calculating the position of the GNSS receiver.
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45. A method for calculating a position of a global navigation satellite system (GNSS) receiver by using a time for periodic signalling events to travel from a plurality of satellites to the GNSS receiver, the method comprising, in respect of each satellite:
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receiving, by the GNSS receiver, one of the periodic signalling events from the satellite; determining, by a processor of the GNSS receiver, an initial estimate of transit time for the periodic signalling event to travel from the satellite to the GNSS receiver; and determining, by the processor, an expected transit time for the periodic signalling event to travel from the satellite to the GNSS receiver based on an estimated current position of the GNSS receiver and a predetermined estimate of a position of the satellite; the method further comprising; designating, by the processor, one of the plurality of satellites as a reference satellite; comparing, by the processor, the initial estimate of the transit time and the expected transit time for each non-reference satellite with the initial estimate of the transit time and the expected transit time for the reference satellite, respectively, to form respective residuals that are representative of a combined error in the expected transit times; and calculating, by the processor, the position of the GNSS receiver, without calculating an integer part in the initial estimates of the transit times, using the residuals.
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46. A non-transitory computer-readable medium encoded with instructions that when executed by a processor cause the processor to calculate a position of a global navigation satellite system (GNSS) receiver using a time for periodic signalling events to travel from a plurality of satellites to the GNSS receiver, wherein the instructions cause the processor to, in respect of each satellite:
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receive one of the periodic signalling events from the satellite at the GNSS receiver; determine an initial estimate of a transit time for the periodic signalling event to travel from the satellite to the GNSS receiver; and determine an expected transit time for the periodic signalling event to travel from the satellite to the GNSS receiver based on an estimated current position of the GNSS receiver and a predetermined estimate of a position of the satellite; designate one of the plurality of satellites as a reference satellite; compare the initial estimate of the transit time and the expected transit time for each non-reference satellite with the initial estimate of the transit time and the expected transit time for the reference satellite, respectively, to form respective residuals that are representative of a combined error in the expected transit times; and calculate the position of the GNSS receiver, without calculating an integer part in the initial estimates of the transit times, using the residuals.
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Specification