Leland Stanford Junior University

Integrinautics Corporation

Bradford W Parkinson

David G Lawrence

Clark Emerson Cohen

John David Powell

Henry S Cobb

Boris S Pervan

Matthew Rabinowitz

David M Bevly

Michael L O'Connor

Andrew Karl Wilhelm Rekow

Changdon Kee

Thomas Bell

Gabriel H Elkaim

The present invention provides for a method and apparatus for providing navigation and positioning for at least one or more slave vehicles, wherein the slave vehicles provide their own navigation based on a location of a master vehicle. The method and apparatus allow a slave vehicle to receive a location of a master vehicle and a location of the slave vehicle. Once the location of the vehicles are known, the slave vehicle determines a desired position based on the master vehicle location, determines if adjustments are needed to position the first slave vehicle at the desired position and implements the adjustments if adjustments are needed. The slave vehicle is capable of operating in one of a plurality of modes and further is capable of transitioning from a first mode of operation to a second mode of operation in optimizing navigation and control.

Method and apparatus for vehicle control, navigation and positioning

Disclosed herein is a system for rapidly resolving position with centimeter-level accuracy for a mobile or stationary receiver &lsqb; This is achieved by estimating a set of parameters that are related to the integer cycle ambiguities which arise in tracking the carrier phase of satellite downlinks &lsqb; In the preferred embodiment, the technique involves a navigation receiver &lsqb; simultaneously tracking transmissions &lsqb; from Low Earth Orbit Satellites (LEOS) &lsqb; together with transmissions &lsqb; from GPS navigation satellites &lsqb; The rapid change in the line-of-sight vectors from the receiver &lsqb; to the LEO signal sources &lsqb; due to the orbital motion of the LEOS, enables the resolution with integrity of the integer cycle ambiguities of the GPS signals &lsqb; as well as parameters related to the integer cycle ambiguity on the LEOS signals &lsqb; These parameters, once identified, enable real-time centimeter-level positioning of the receiver &lsqb; In order to achieve high-precision position estimates without the use of specialized electronics such as atomic clocks, the technique accounts for instabilities in the crystal oscillators driving the satellite transmitters, as well as those in the reference &lsqb; and user &lsqb; receivers. In addition, the algorithm accommodates as well as to LEOS that receive signals from ground-based transmitters, then re-transmit frequency-converted signals to the ground.

System using leo satellites for centimeter-level navigation

A GPS system and method for generating precise position determinations. The GPS system includes a ground based GPS reference system which receives with a reference receiver GPS signals and makes phase measurements for the carrier components of the GPS signals. The GPS reference system then generates and broadcasts an initialization signal having a carrier component and a data link signal having a data component. The data component of the data link signal contains data representing the phase measurements made by the reference receiver. The GPS system also includes a GPS mobile system which receives with a mobile position receiver the same GPS signals as were received by the reference system. In addition, the GPS position receiver receives the data link and initialization signals broadcast by the reference system. The GPS position receiver then makes phase measurements for the carrier components of the GPS signals during and after an initialization period and makes phase measurements for the initialization signal during the initialization period. In response to the phase measurements made by both the reference receiver and the position receiver during the initialization period, the position receiver generates initialization values representing resolution of the integer ambiguities of the received signals. In response to the initialization values and the phase measurements made by both the receivers after the initialization period, the position receiver generates precise position determinations to within centimeters of the exact location.

System and method for generating precise position determinations

Described is an automatic control system for land (and possible marine) vehicles based on carrier phase differential GPS (CPGPS). The system relies on CPGPS to determine vehicle position and attitude very precisely (position to within 1 cm and attitude to within 0.1.degree.). A system incorporates a technique to calculate and compensate for antenna motion due to vehicle roll and pitch. One aspect of the system utilizes an intelligent vehicle controller that recognizes and adapts to changing conditions, such as vehicle speed, implements towed by the vehicle, soil conditions, and disturbance level. The system provides the capability to control the vehicle on various paths, including straight lines and arbitrary curves. Also described is a technique for initialization and vehicle control using only a single pseudolite.

Method and system for automatic control of vehicles based on carrier

Novel techniques are disclosed for eliminating multipath errors, including mean bias errors, in pseudorange measurements made by conventional global positioning system receivers. By correlating the multipath signals of different satellites at their cross-over points in the sky, multipath mean bias errors are effectively eliminated. By then taking advantage of the geometrical dependence of multipath, a linear combination of spherical harmonics are fit to the satellite multipath data to create a hemispherical model of the multipath. This calibration model can then be used to compensate for multipath in subsequent measurements and thereby obtain GPS positioning to centimeter accuracy.

Multipath calibration in GPS pseudorange measurements

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Los Altos, CA, United States of America

Bradford W Parkinson