Pseudolite-aided method for precision kinematic positioning
First Claim
1. A method for determining the relative position of a secondary receiving antenna with respect to a reference receiving antenna in a satellite-based positioning system, the method comprising the steps of:
- making carrier phase measurements based on the reception of a carrier signal from each of a plurality N of satellites, where N is the minimum number of satellites needed to compute the relative position of the secondary antenna;
deriving from the carrier phase measurements an initial set of potential solutions for the relative position, wherein the initial set of potential solutions all fall within a region of uncertainty defined by a sphere having a radius equal to the maximum distance between the two antennas, and wherein multiple potential solutions arise because of whole-cycle ambiguity of the carrier signal;
positioning at least one pseudolite transmitter on the ground at a location near an intended path of travel of the secondary antenna;
making redundant carrier phase measurements based on the reception of a carrier signal from the at least one pseudolite; and
eliminating false solutions from the initial set of potential solutions, based on a comparison of the redundant carrier phase measurements with the initial set of potential solutions, to reduce number of potential solutions to close to one, whereby the number of potential solutions is not increased by use of the redundant carrier phase measurements.
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Abstract
A technique using pseudo-satellites, or "pseudolites," for resolving whole-cycle ambiguity that is inherent in phase-angle measurments of signals received from multiple satellite-based transmitters in a global positioning system. The relative position of a secondary receiving antenna with respect to a reference antenna is approximately known or approximately initially determined and then measurements from a minimum number of satellites are used to determine an initial set of potential solutions to the relative position of the secondary antenna that fall within a region of uncertainty surrounding the approximate position. Redundant measurements are taken from one or more pseudolites, and used to progressively reduce the number of potential solutions to close to one. Each pseudolite is positioned such that its angular position as seen from the secondary antenna changes rapidly as the antenna is moved along an intended path, thus providing rapidly changing redundant measurements, which are used to eliminate false solutions more quickly. The disclosed technique produces rapid elimination of false solutions and permits real-time computation of relative position in kinetic positioning applications.
151 Citations
10 Claims
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1. A method for determining the relative position of a secondary receiving antenna with respect to a reference receiving antenna in a satellite-based positioning system, the method comprising the steps of:
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making carrier phase measurements based on the reception of a carrier signal from each of a plurality N of satellites, where N is the minimum number of satellites needed to compute the relative position of the secondary antenna; deriving from the carrier phase measurements an initial set of potential solutions for the relative position, wherein the initial set of potential solutions all fall within a region of uncertainty defined by a sphere having a radius equal to the maximum distance between the two antennas, and wherein multiple potential solutions arise because of whole-cycle ambiguity of the carrier signal; positioning at least one pseudolite transmitter on the ground at a location near an intended path of travel of the secondary antenna; making redundant carrier phase measurements based on the reception of a carrier signal from the at least one pseudolite; and eliminating false solutions from the initial set of potential solutions, based on a comparison of the redundant carrier phase measurements with the initial set of potential solutions, to reduce number of potential solutions to close to one, whereby the number of potential solutions is not increased by use of the redundant carrier phase measurements. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification