GNSS-BASED TRACKING OF FIXED OR SLOW-MOVING STRUCTURES
First Claim
1. A GNSS-based method of tracking the movement of a structure, which method comprises the steps of:
- providing a GNSS receiver;
providing an antenna array comprising multiple GNSS antennas each selectively connected to said receiver;
mounting said antennas on the structure at fixed locations relative to each other and said structure;
providing an antenna switch control connected to said antennas;
connecting said antenna switch control to a receiver input;
sequentially switching the receiver input among said antennas with said antenna input switch;
providing a processor connected to said receiver and said antenna switch control;
providing a first set of GNSS signals from said antennas to said processor via said receiver;
computing a corresponding first set of GNSS-based locations of said antennas when connected to said receiver;
storing with said processor said first set of GNSS-based locations of said antennas;
providing a second set of GNSS signals from said antennas to said processor via said receiver;
computing with said processor a corresponding second set of GNSS-based locations of said antennas when connected to said receiver;
comparing with said processor said first and second sets of antenna locations; and
providing an output from said processor representing a location change of at least one of said antennas based on said GNSS-based location comparisons.
4 Assignments
0 Petitions
Accused Products
Abstract
A multi-antenna GNSS system and method provide earth-referenced GNSS heading and position solutions. The system and method compensate for partial blocking of the antennas by using a known attitude or orientation of the structure, which can be determined by an orientation device or with GNSS measurements. Multiple receiver units can optionally be provided and can share a common clock signal for processing multiple GNSS signals in unison. The system can optionally be installed on fixed or slow-moving structures, such as dams and marine vessels, and on mobile structures such as terrestrial vehicles and aircraft.
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Citations
22 Claims
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1. A GNSS-based method of tracking the movement of a structure, which method comprises the steps of:
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providing a GNSS receiver; providing an antenna array comprising multiple GNSS antennas each selectively connected to said receiver; mounting said antennas on the structure at fixed locations relative to each other and said structure; providing an antenna switch control connected to said antennas; connecting said antenna switch control to a receiver input; sequentially switching the receiver input among said antennas with said antenna input switch; providing a processor connected to said receiver and said antenna switch control; providing a first set of GNSS signals from said antennas to said processor via said receiver; computing a corresponding first set of GNSS-based locations of said antennas when connected to said receiver; storing with said processor said first set of GNSS-based locations of said antennas; providing a second set of GNSS signals from said antennas to said processor via said receiver; computing with said processor a corresponding second set of GNSS-based locations of said antennas when connected to said receiver; comparing with said processor said first and second sets of antenna locations; and providing an output from said processor representing a location change of at least one of said antennas based on said GNSS-based location comparisons. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A GNSS-based method of tracking the relative movement of a fixed or slow-moving structure, which method comprises the steps of:
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providing a master receiver unit with a master GNSS receiver and a master RF transmitter; providing a master GNSS antenna connected to said master receiver; providing a slave receiver unit with a slave GNSS receiver and a slave RF receiver; providing a slave antenna array comprising multiple GNSS antennas each selectively connected to said slave receiver; mounting said slave antennas on the structure at fixed locations relative to each other and said structure; locating said antenna array on said structure with at least a portion of said antennas being blocked by said structure from receiving signals from at least a portion of the satellites in the GNSS constellation; providing an antenna switch control connected to said slave antennas; connecting said antenna input switch control to a receiver input; switching the receiver input among said slave antennas with said antenna input switch; providing a processor connected to said receiver and said antenna switch control; providing a first set of GNSS signals from said antennas to said processor via said receivers; transmitting real-time kinematic (RTK) carrier phase correction signals from said master RF transmitter to said slave RF receiver; with the slave receiver unit, determining the relative locations and the relative ambiguities of the multiple antennas using said distance, geometry and clock constraints in an attitude and position solution; storing said attitude and position solution; storing current GNSS carrier phase observations; time-tag matching said stored attitude and position solution and said GNSS carrier phase observations with data from the base receiver unit to avoid extrapolation errors; forming single or double difference equations and solving for the global ambiguities using said relative antenna attitudes and positions; synchronizing a clock signal between said receivers; said processor using said RTK correction signals for deriving a position and attitude solution for said structure. computing a corresponding first set of GNSS-based locations of said antennas when connected to said receivers; storing with said processor said first set of GNSS-based locations of said antennas; providing a second set of GNSS signals from said antennas to said processor via said receivers; computing with said processor a corresponding second set of GNSS-based locations of said antennas when connected to said receivers; comparing with said processor said first and second sets of antenna locations; providing an output from said processor representing a location change of at least one of said antennas based on said GNSS-based location comparisons; using GNSS signals from multiple antennas to compute antenna locations relative to each other based on;
1) partial GNSS constellation observations; and
2) known locations of said antennas relative to each other;taking said GNSS signal readings at respective antennas at intervals corresponding to the orbital cycles of said satellites and the Earth'"'"'s rotation; said processor averaging said different GNSS signal multipath effects and thereby reducing or eliminating multipath errors from said GNSS-defined antenna locations on said structure; receiving common satellite signals at multiple said antennas; separating each pair of said antennas by a distance greater than the carrier phase wavelength of the GNSS signals; providing said slave receiver with a temperature sensor connected to said slave processor; providing a thermocouple connected to said temperature sensor; and programming said slave processor with a temperature look-up table to compensate for ambient temperature at said slave antennas with input from said thermocouple and said temperature sensor.
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15. A system for determining a GNSS-defined position of a single point fixedly positioned on a slow-moving, structure including a GNSS signal-blocking obstruction, which system comprises:
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master and slave GNSS receivers; master and slave antennas connected to said master and slave receivers respectively and mounted in fixed relation with known geometry and distances relative to each other and to said single point, said antennas being mounted on opposite sides of said mobile structure below said signal-blocking obstruction; a common clock or synchronized clocks connected to said receivers for simultaneously processing GNSS signals received by said antennas; an orientation device mounted on said structure for determining an orientation of said structure; and computing means for determining the GNSS-defined position of said single point using; (1) GNSS signals received by said master and slave receivers from said master and slave antennas respectively and input to said computing means, said signal-blocking obstruction blocking GNSS signals from certain satellites from said antennas whereby each antenna receives signals from no more than three satellites and collectively said antennas receive GNSS signals from at least four satellites;
(2) the known relative orientation and fixed distances and geometry of said master and slave antennas relative to each other and to said structure;
(3) the known relative orientation and fixed distances and geometry of said single point relative to said master and slave antennas and to said structure; and
(4) the orientation of said structure based on input from said orientation device. - View Dependent Claims (16, 17, 18)
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19. A system for determining a GNSS-defined position of a point fixedly positioned on a fixed or slow-moving, mobile structure including a GNSS signal-blocking obstruction, which system comprises:
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master and slave GNSS receivers; master and slave antennas connected to said master and slave receivers respectively and mounted in fixed relation with known geometry and distances relative to each other and to said single point, said antennas being mounted on opposite sides of said mobile structure below said signal-blocking obstruction; a common clock or synchronized clocks connected to said receivers for simultaneously processing GNSS signals received by said antennas; an orientation device mounted on said structure for determining an orientation of said structure; and computing means for determining the GNSS-defined position of said single point using; (1) GNSS signals received by said master and slave receivers from said master and slave antennas respectively and input to said computing means, said signal-blocking obstruction blocking GNSS signals from certain satellites from said antennas whereby each antenna receives signals from no more than three satellites and collectively said antennas receive GNSS signals from at least four satellites;
(2) the known relative orientation and fixed distances and geometry of said master and slave antennas relative to each other and to said structure;
(3) the known relative orientation and fixed distances and geometry of said single point relative to said master and slave antennas and to said structure; and
(4) the orientation of said structure based on input from said orientation device. - View Dependent Claims (20, 21, 22)
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Specification