Centimeter accurate global positioning system receiver for on-the-fly real-time kinematic measurement and control
First Claim
1. An on-the-fly real-time kinematic (OTF-RTK) system for use with the global positioning system (GPS), comprising:
- a reference station (12,
126) including a GPS satellite navigation receiver and measurement means (70, 72, 74,
76) connected to output (19,
128) single carrier frequency code and phase measurements from a fixed location;
a rover unit (14,
130) including a GPS satellite navigation receiver and measurement means (90, 92, 94,
96) connected to output (132) single carrier frequency code and phase measurements from a movable vehicle and including an output for position determinations;
double-differencing means (98) connected to receive phase and code measurement information transmitted from the reference station and rover unit and then difference said measurement information to subtract out satellite-common and receiver-common clock errors, wherein substantially unbiased phase and code measurement information is output;
integer ambiguity resolution means (106) connected to the double-differencing means and including integer search means for searching carrier frequency phase and code measurements, wherein a unique solution for whole-cycle carrier phase ambiguity is provided at an output to computer navigation means for positioning determining with centimeter-level accuracy and on-the-fly initialization;
a navigation computer (108) connected to receive said unbiased phase and code measurement information and to provide an output of near-continuous position estimates of the rover unit; and
robotic control means (134) connected to receive said near-continuous position estimates from the navigation computer in the rover unit for servo-controlling a remote-controlled vehicle according to a plurality of comparisons made between said near-continuous position estimates and a predetermined construction model of ideal positions for said remote-controlled vehicle.
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Accused Products
Abstract
A system embodiment of the present invention comprises a fixed and a roving pair of four-observable GPS receivers and a communication link between them for double differencing code and carrier measurements. Carrier phase integer ambiguities are resolved efficiently by searching the simultaneous narrow-lane intersections of both the L1 and L2 wave fronts propagated by the GPS satellites being tracked. External constraint information, such as elevation, is additionally used to speed up integer ambiguity resolution. Data between the reference station and the rover is communicated in compressed form at a regular interval, e.g., once a second at each epoch, and demi-measurements of carrier phase are obtained more frequently, e.g., ten times a second, and used to propagate solutions between epochs.
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Citations
9 Claims
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1. An on-the-fly real-time kinematic (OTF-RTK) system for use with the global positioning system (GPS), comprising:
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a reference station (12,
126) including a GPS satellite navigation receiver and measurement means (70, 72, 74,
76) connected to output (19,
128) single carrier frequency code and phase measurements from a fixed location;a rover unit (14,
130) including a GPS satellite navigation receiver and measurement means (90, 92, 94,
96) connected to output (132) single carrier frequency code and phase measurements from a movable vehicle and including an output for position determinations;double-differencing means (98) connected to receive phase and code measurement information transmitted from the reference station and rover unit and then difference said measurement information to subtract out satellite-common and receiver-common clock errors, wherein substantially unbiased phase and code measurement information is output; integer ambiguity resolution means (106) connected to the double-differencing means and including integer search means for searching carrier frequency phase and code measurements, wherein a unique solution for whole-cycle carrier phase ambiguity is provided at an output to computer navigation means for positioning determining with centimeter-level accuracy and on-the-fly initialization; a navigation computer (108) connected to receive said unbiased phase and code measurement information and to provide an output of near-continuous position estimates of the rover unit; and robotic control means (134) connected to receive said near-continuous position estimates from the navigation computer in the rover unit for servo-controlling a remote-controlled vehicle according to a plurality of comparisons made between said near-continuous position estimates and a predetermined construction model of ideal positions for said remote-controlled vehicle.
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2. An on-the-fly real-time kinematic (OTF-RTK) system, comprising:
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a reference station (12,
126) including a satellite navigation receiver and measurement means connected to output carrier frequency code and phase measurements from a fixed location;a rover unit (14,
130) including a satellite navigation receiver and measurement means connected to output carrier frequency code and phase measurements from a movable vehicle;double-differencing means (98) connected to receive phase and code measurement information transmitted from the reference station and rover unit and the difference said measurement information to subtract out satellite-common and receiver-common clock errors, wherein substantially unbiased phase and code measurement information is output; integer ambiguity resolution means (106) connected to the double-differencing means and including integer search means for simultaneously searching the phase of said carrier frequency phase measurements, wherein a unique solution for whole-cycle carrier phase ambiguity is provided at an output to a navigation computer means for positioning determining with centimeter-level accuracy and on-the-fly initialization; and a navigation computer (108) connected to receive said unbiased phase and code measurement information and to provide an output of near-continuous position estimates of the rover unit. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9)
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Specification