Abstract: A method and apparatus which allows for corrections to be made to the path of a vehicle when an automatic steering control feature of a guidance control system is in operation. A sensor is coupled to the steering system detects movement of the steering wheel by the operator. When the operator moves the steering wheel the logic of the correction controller adjusts the travel path of the vehicle to correspond to the movement of the steering wheel. In one embodiment the travel path is adjusted by instructions transmitted to the controller of the guidance control system. Correction of the travel path may also be obtained by the operation of a keypad or a joystick.

Abstract: A method and apparatus for coupling data from an external data device to a position determination device. An Auxiliary Data Transmission Unit (ADTU) that includes a radio transmitter couples to the external data device. The ADTU receives serial data from the external data device and encodes the received serial data into a format suitable for receipt by the position determination device. The encoded data is then modulated to produce a radio signal that is transmitted to the position determination device in a scheme that permits multiple devices to communicate with the position determination device without interference.

Abstract: An antenna comprises a signal radiator, a ground plane spaced apart from the radiator, and a dielectric separator between the radiator and the ground plane. The separator comprises at least two positions having different dielectric constants. In a preferred embodiment, it comprises a material such as FR-4 that has a dielectric constant and a loss tangent substantially higher than those of air and is formed with at least one void reducing the loss tangent of the separator. The antenna strikes an effective compromise between the dielectric constant and loss tangent and is well suited to transmit and receive GPS signals.

Abstract: A first position determining device at a known position transmits a data signal identifying the known position. A second position determining device is responsive to the data signal and movable to a position near but displaced from a survey point. The position of the second position determining device is determined relative to the known position, and the range and bearing of the survey point is determined relative to the second position determining device.

Abstract: A global positioning system (GPS) controlled paint spray system. The system includes a paint sprayer driver program and a GPS paint sprayer. The paint sprayer driver program enables a user of a standard drawing program using a standard personal computer to generate a print file for a drawing pattern. The GPS paint sprayer includes a GPS receiver, a geographical converter for enabling a user to convert the drawing pattern to geographical locations, a location comparator for detecting a location match between the geographical locations of the drawing pattern and a current GPS-based location, and a spray nozzle to spraying paint for matched locations.

Abstract: A Global Positioning System (GPS) receiver includes multiple correlation segments that can operate in parallel. Each correlation segment has a separate set of accumulators associated with it, embodied in random access memory (RAM). In each of the correlation segments, correlation data associated with an input code and a reference code are generated. The multiple correlation segments are cross-coupled, so that correlation data generated in each correlation segment are added to correlation data generated in each other correlation segment. The combined correlation data in each correlation segment are stored in the accumulators of each corresponding correlation segment, such that the accumulators of only one correlation segment are accessed at a time, reducing power consumption resulting from accessing RAM.

Abstract: A geographical position/image capturing system stores object images and position coordinates as digital data. The system incorporates a geo-addressed map data base and geo-positioning device for relating the position of the system at the time the image is captured to the captured digital image data and the geo-addressed map. A point-of-interest feature data base is linked to the image data and the position data, by hyper-media links. Digital multi-media entities such as graphics, video clips, audio streams and the like can be digitally stored and retrieved based on hyper-media links coupling the entities to the object images, the map position and feature data base. A playback unit incorporating an image viewer communicates with the stored digital digital image data, the multi-media entities, the map data base, and the feature data base and allows modified images of selected portions of the images and other data to be viewed by a user.

Abstract: The method of supplementing the satellite data by the satellite-calibrated baro data when the receiver autonomous integrity monitoring function (RAIM) is unavailable and when the horizontal protection level (HPL) does not satisfy the horizontal alert limit (HAL) requirement is disclosed. The baro data is adjusted to compensate for the lack of baro calibration in the position solution domain. The HPL is re-computed using the satellite-calibrated adjusted baro data. The re-computed HPL could satisfy the HAL requirement which would make the RAIM function available when it would be otherwise unavailable.

Abstract: A GPS receiver having a fast time to lock to a GPS signal by storing a time period of an incoming GPS signal in a signal memory and rapidly comparing the signal memory against locations in a replica memory having stored GPS signal replicas. The GPS receiver includes a memory-based search engine for acquiring the GPS signal so that it may be tracked. The memory-based search engine includes a signal memory for storing a millisecond of a digitized GPS signal, a replica memory section for storing replicas representative of the digitized GPS signal for all possible frequency differences between the GPS carrier frequency and a local reference frequency and phase offsets between the GPS code phase and a local reference time, and a GPS memory comparator for comparing the stored signal in signal memory to the stored replicas in replica memory and issuing an acquisition detection signal when the level of the comparison is greater than a selected threshold.

Abstract: A GPS receiver having a fast time to first fix by comparing measured range rates for GPS satellites to GPS satellite velocities that are calculated from coarse GPS satellite orbital parameters. The coarse GPS satellite parameters are GPS almanac parameters or GPS ephemeris parameters that are older than the GPS-specified curve fit interval. The GPS receiver includes a satellite velocity calculator and a satellite line-of-sight calculator using the coarse GPS satellite orbital parameters previously stored in memory for calculating GPS satellite velocities and unit vectors to GPS satellites, respectively; a range rate measurer using GPS signal carrier measurements for determining range rates to GPS satellites; a user velocity calculator using the satellite velocities, unit vectors, and range rates for calculating a user velocity; and a user location integrator for integrating the user velocity from the last user location for a first location fix.

Abstract: A system for differential navigation of an autonomous vehicle in the location with the limited visibility of the sky is disclosed. The system employs a plurality of satellites, a plurality of ground transmitters, and a base station. Different configurations for the minimum number of the satellites and the minimum number of ground transmitters are disclosed.

Abstract: Method and system for determining a position of a platform using a set of range measurements between the platform and a set of known positions that avoids the frequent recalculation of square-roots in range predictions. The platform state estimate is updated by substituting the difference between the square of the range measurement and the square of the distance from the assumed position of the platform to the known position to which the range measurement corresponds scaled by the inverse twice distance between the predicted position of the platform and the known position, for each of the measurement residuals. The predicted state of the platform is updated until the platform state converges on a limit to a desired accuracy.

Abstract: A system for monitoring operation and location of a first moving vehicle relative to a second moving vehicle. A minimum separation distance between the first and second vehicles is estimated, based on the first vehicle velocity, and optionally on the second vehicle velocity, using location determination (LD) signals received from satellite-based transmitters from GPS, GLONASS and LEO satellites, or from ground-based signal sources such as LORAN signal towers, and using ranging signals from SONAR, RADAR or a similar system. The minimum separation distance is compared with the actual separation distance at selected times, and a vehicle driver is advised if the actual separation distance is too small, if the separation distance is decreasing too quickly, or if the second vehicle velocity is decreasing too quickly. The second vehicle may travel in the same traffic lane, in an adjacent lane, or on a road that intersects the road used by the first vehicle.

Abstract: The present invention discloses the apparatus and the method for calibrating a Narrow Band Receiver in real time for code group delay errors in the signals transmitted by a Narrow Band Transmitter. The apparatus includes a Calibration circuit used to generate a calibration signal that is substantially free from code delay errors, and that is substantially similar to the signal emanating from the Narrow band Transmitter. The calibration signal can be used by the Narrow Band receiver to measure and offset the group delay errors in real time.

Abstract: A task description is stored in a database accessible by a mobile computer system. The mobile computer system receives positioning information corresponding to its geographic location and indexes the database based on the positioning information when the information indicates that the mobile computer system is in a geographic location that facilitates completion of a task associated with the task description. The database may be resident in the mobile computer system or accessible in other ways, for example, via the Internet. The task description preferably includes a geocode which corresponds to the geographic location at which completion of the task may be facilitated. The task description may also include textual, voice or other message which can be displayed and/or played back to a user. The positioning information may be obtained from a GPS satellite, a GLONASS satellite or a pseudolite. The mobile computer system may be a portable unit, such as a PDA, or integrated within a vehicle.

Abstract: The mobile unit equipped with the satellite positioning system augmented by the laser positioning system is disclosed. The usage of the satellite positioning system allows the user to determine the coordinate of the laser reflectors prior to the range measurements. The range measurements are performed by the navigational computer using the laser scanning and rotating beam to obtain the range data between the mobile unit and a plurality of laser reflectors, and using the satellite positioning system to obtain the range data between the mobile unit and a plurality of visible navigational satellites. The obtained range data and the laser reflector coordinate data allows the user to perform the navigation of the mobile unit.

Abstract: A method and apparatus for processing multipath reflection effects in timing systems is disclosed in which a determination is made of whether a received signal is a reflected signal. A detector provides from an input signal a pair of signals representative of whether the input signal contained right-hand circularly polarized and left-hand circularly polarized components. The representative signals are separately processed in synchronized logic circuits to determine relative power levels. The power levels are compared to determine the nature of the dominant polarization of the input signal.

Abstract: A method and apparatus for calibrating sensors of a tool positioning mechanism on a mobile machine are provided. The mobile machine includes a tool, a tool positioning mechanism having a plurality of sensors for providing signals indicative of the physical configuration of the mechanism, a satellite positioning system, and a plurality of positioning system antennas. One of the antennas is detachably mounted on the tool while an other antenna is mounted to a location on the machine other than on the tool. With the positioning mechanism configured so that the tool is at its maximum height, the satellite positioning system is operated to acquire real-time kinematic (RTK) data from the antennas and to process the RTK data to precisely determine the position of the tool. The sensors are then calibrated based on the precisely determined position of the tool.

Abstract: Method and apparatus for synchronizing to a reference signal the timing of a received composite, code phase SATPS signal, such as a GPS or GLONASS signal, that consists of a preferred, interference-free signal distorted by at least one interfering signal, to determine an undistorted timing point, such as the preferred signal time of arrival. A first autocorrelation function ACI(&tgr;) is generated between the preferred, interference-free signal and a reference signal that replicates the preferred signal, as a function of the time shift &tgr; between the two signals. A second autocorrelation signal ACM(&tgr;) is measured between the reference signal and the incoming signal.

Abstract: A method for fast acquisition, in as little as 6-15 seconds, of signals from a satellite in a Satellite Positioning System (SATPS), such as GPS or GLONASS, that does not require permanent storage of satellite ephemeris information at an SATPS ground station. This SATPS signal acquisition method can be used whenever the “new” station initially powers up or has lost lock on one or more SATPS signals that must be (re)acquired. A reference SATPS station provides the new SATPS station with an estimated reference station location and ephemeris information for one or more identified SATPS satellites visible from the reference station. The new station receives and uses this information to establish carrier frequency ranges to search for the identified SATPS satellite, by limiting the search to a reduced frequency range based upon estimated Doppler shift of SATPS signals received from this satellite.