Abstract: A vehicle position determination system and method provide accurate vehicle positioning using a global positioning system. Spatial bias techniques are used to improve positioning accuracy while the vehicle is in the midst of a relatively linear path and is not approaching a drastically nonlinear path. The use of spatial bias techniques is suspended while the vehicle is approaching or in a drastically nonlinear path.

Abstract: A system and method for using coordinate data indicative of the present location of a vehicle to determine which state the vehicle is in. A receiver obtains the coordinate data and compares it to state boundary coordinate information stored in memory. The angles created by the present coordinate location and each pair of adjacent points along a state's boundary are added. A resulting sum of two times pi (radians) indicates that the present state falls within the state boundary, a result of zero indicates otherwise.

Abstract: A system (400) for positioning and navigating an autonomous vehicle (310) allows the vehicle (310) to travel between locations. Position information (432) is derived from global positioning system satellites (200, 202, 204, and 206) or other sources (624) when the satellites (200, 202, 204, and 206) are not in the view of the vehicle (310). Navigation of the vehicle (310) is obtained using the position information (432), route information (414), obstacle detection and avoidance data (416), and on board vehicle data (908 and 910).

Abstract: A differential system and method for computing the position of a mobile receiver at or near the surface of the Earth using a base receiver having a known position and using a satellite-based navigation system including a constellation of navigation satellites is disclosed. The method includes the following steps. A base position estimate is computed for the base receiver using a pseudorange from a first satellite and ranges from two other satellites. A first vector difference between the base position estimate and the known position of the base receiver is computed. An initial position estimate is computed for the mobile receiver. A refined position estimate is computed for the mobile receiver using a pseudorange from the first satellite and ranges from two other satellites. A second vector difference between the initial position estimate and the refined position estimate of the mobile receiver is computed.

Abstract: A system and method for estimating the terrestrial position of a vehicle is provided. The system receives electromagnetic signals from a single satellite and responsively produces successive ranges from the satellite to the vehicle and respective successive positions of the satellite. The vehicle's position is determined as a function of the successive ranges and positions.

Abstract: The present invention includes a system for estimating the terrestrial position of a vehicle. The system receives electromagnetic signals from a plurality of sources and responsively producing respective ranges from each of said sources to said vehicle and respective positions of each of said sources. The system projects the position of one of said sources to the opposite side of the Earth and responsively determining a projected position and a projected range. The vehicle's position is determined as a function of said ranges and positions.

Abstract: Systems and methods allow for the accurate determination of the terrestrial position of an autonomous vehicle in real time. A first position estimate of the vehicle 102 is derived from satellites of a global positioning system and/or a pseudolite(s). The pseudolite(s) may be used exclusively when the satellites are not in the view of the vehicle. A second position estimate is derived from an inertial reference unit and/or a vehicle odometer. The first and second position estimates are combined and filtered using novel techniques to derive a more accurate third position estimate of the vehicle's position. Accordingly, accurate autonomous navigation of the vehicle can be effectuated using the third position estimate.

Abstract: An apparatus and method are disclosed for determining the position of a vehicle at or near the surface of the Earth using navigation signals from a satellite-based navigation system. Precise position estimates are achieved by reducing effective receiver noise. A plurality of receiver means each compute a pseudorange for each satellite. A signal optimizer then uses the pseudoranges from each receiver means to compute an optimal pseudorange for each satellite. A processor means computes a vehicle position from the optimal pseudoranges.

Abstract: The position of a satellite in a satellite based navigation system is determined without reliance on satellite ephemeris data. Orbital parameters are computed for each satellite. The orbital parameters can then be used to predict the position of each satellite at any time. Subsequent ephemeris data may be compared to a predicted satellite position to determine whether the ephemeris data is corrupt. The orbital parameters may be determined by: computing a pseudorange and a velocity for a selected satellite for a plurality of times, computing at least three estimated positions of the satellite from the pseudoranges and velocities, and computing orbital parameters for the satellite from the three estimated positions.

Abstract: Systems and methods allow for the accurate determination of the terrestrial position of an autonomous vehicle in real time. A first position estimate of the vehicle 102 is derived from satellites of a global positioning system and/or a pseudolite(s). The pseudolite(s) may be used exclusively when the satellites are not in the view of the vehicle. A second position estimate is derived from an inertial reference unit and/or a vehicle odometer. The first and second position estimates are combined and filtered using novel techniques to derive a more accurate third position estimate of the vehicle's position. Accordingly, accurate autonomous navigation of the vehicle can be effectuated using the third position estimate.

Abstract: The accuracy of a vehicle position estimate generated using a satellite-based navigation system is improved by accounting for non-linear errors in the vehicle position computations. The standard navigation equation is modified to include the error coefficients .alpha., .beta., .gamma. and .delta.. .alpha. is used to model errors in the x dimension. .beta. is used to model errors in the y dimension. .gamma. is used to model errors in the z dimension. .delta. is used to model errors in the pseudoranges. The error coefficients may be computed using an open-ended GPS system or a differential GPS system. The error coefficients may be computed in real time or may be computed once and used for a period thereafter. Once computed, the error coefficients are factored into the computation of a vehicle position estimate for increased precision.

Abstract: Systems and methods allow for the accurate determination of the terrestrial position of an autonomous vehicle in real time. A first position estimate of the vehicle 102 is derived from satellites of a global positioning system and/or a pseudolite(s). The pseudolite(s) may be used exclusively when the satellites are not in the view of the vehicle. A second position estimate is derived from an inertial reference unit and/or a vehicle odometer. The first and second position estimates are combined and filtered using novel techniques to derive a more accurate third position estimate of the vehicle's position. Accordingly, accurate autonomous navigation of the vehicle can be effectuated using the third position estimate.

Abstract: An apparatus and method for determining the position of a vehicle relative to the center of the Earth uses navigation signals from a satellite based navigation system which includes a plurality of satellites orbiting the Earth. In one embodiment, a plurality of antennas are mounted on the vehicle. The distance between the antennas is precisely known. This distance is used to constrain the solution of a vehicle position estimate to improve the accuracy of the position estimate. In another embodiment, a plurality of receiver systems are used in place of the plurality of antennas. In yet another embodiment, a plurality of base stations with known positions are used to constrain the solution of the vehicle position estimate.

Abstract: An apparatus and method are adapted for detecting an end-of-fill condition of an actuator having a varying control volume is provided. The end-of-fill condition corresponds to the varying control volume being pressurized to a predetermined end-of-fill pressure. The apparatus comprises a solenoid having a coil and an armature. The armature is movable relative to the coil in response to energization of the coil. A valve delivers a flow of fluid to the actuator. The fluid flow having a rate responsive to the movement of the armature. The apparatus and method controllably energizes the coil with a control current. The apparatus and method detects a flyback current in the coil, detects a change in the level of noise in said flyback current, and responsively producing an end-of-fill signal in response to the change being greater than a predetermined threshold.

Abstract: An apparatus determines the payload carried in a work vehicle by monitoring the pressure of a fluid contained within front and rear suspension struts. The struts are connected in supporting relation between a load carrying portion and a ground engaging portion of the work vehicle such that a compression condition of the strut is detected while the work vehicle is in motion. Moreover, a pressure differential corresponding to the compression condition is indicative of the magnitude of the payload supported by the strut.

Abstract: A dynamic payload monitor measures and displays payload weight for a loader vehicle by sensing the hydraulic pressure of a lift arm cylinder. The payload weight is computed by curve fitting the second cylinder pressure to a second order polynomial, calculating a pressure differential, and then performing interpolation or extrapolation with a pair of pressure versus position or time reference parabolas obtained during calibration. The weight computation algorithms used in the dynamic payload monitor are applicable to a number of work vehicles having at least one work implement linkage and at least one hydraulic cylinder for modifying the linkage geometry.

Abstract: In many applications, a loader performs a loading operation that includes, sequentially: digging and/or crowding a stock pile, racking back the bucket to maintain the load, travelling to a dump site or a transport vehicle while raising the bucket, and finally dumping the load from a raised position. For many devices, such as payload monitors and productivity indicators, it is important to have an indication of which function in the loading operation is being performed. A loading function identifier senses, stores, and averages the hydraulic pressure in a lift cylinder. The sensed and averaged data are compared to a series of predetermined constants to identify the function being performed. The algorithms used in this invention are applicable to a number of work vehicles having at least one work implement linkage and at least one hydraulic cylinder for modifying the linkage geometry.

Abstract: In many applications, it is important to measure and display payload weight for a loader vehicle. The subject apparatus and method senses only the hydraulic pressure of a lift cylinder. The payload weight is computed by curve fitting the sensed cylinder pressure to a second order time dependent polynomial and comparing the time dependent polynomial to one of a series of predetermined second order geometric polynomials. The weight computation algorithms used in the payload monitor are applicable to a number of work vehicles having at least one work implement linkage and at least one hydraulic cylinder for modifying the linkage geometry.

Abstract: A dynamic payload monitor measures and displays payload weight for a loader vehicle operated on a slope by sensing the hydraulic pressure and position of the lift arm cylinders. The payload weight is computed by curve fitting the sensed cylinder pressure and position data to a second order polynomial, and then performing interpolation or extrapolation with a pair of pressure versus position reference parabolas obtained during calibration. Payload weight is corrected for errors caused by operating the loader vehicle on a slope. The weight computation algorithms used in the dynamic payload monitor are applicable to a number of work vehicles having at least one work implement linkage and at least one hydraulic cylinder for modifying the linkage geometry.

Abstract: A dynamic payload monitor measures and displays payload weight for a loader vehicle during tip loading by sensing the hydraulic pressure of the lift and tilt cylinders and the geometry of an implement linkage. The payload weight is computed by curve fitting the sensed lift cylinder pressure and geometry data to a second order polynomial, and then performing interpolation or extrapolation with a pair of pressure versus position reference parabolas obtained during calibration. Tilt cylinder curves are derived by curve fitting tilt cylinder pressure and lift cylinder geometry data to a third order polynomial. The tilt cylinder curves are then compared to a plurality of tabulated tilt cylinder curves. Tip loading conditions are detected and the computed payload weight is modified in response to the magnitude of the tilt cylinder pressure.