Abstract: A method and a system for remote control of a rover over a long base line is disclosed. The system includes a primary base station (PBS), a secondary base station (SBS), a rover, a primary long line data link between PBS and SBS, and a secondary two-way data link between the SBS and the rover. The primary data link and the secondary data link comprise a long baseline feedback loop that is used to transmit the control data to the rover, to adjust the control data, and to transmit back from the rover to the SBS and to the PBS the collected feedback data.

Abstract: A method and apparatus for accurately positioning a tool on a mobile machine are provided. The machine operates within a work area about which one or more stationary laser-based subsystems are positioned. The machine includes an on-board subsystem, which comprises a processor, a satellite positioning system (SPS) receiver, a stored digital terrain model (DTM), and a photosensor for detecting a laser beam. The laser beam provides a reference level that is used to adjust the position of the tool. The on-board subsystem determines the current position of the machine using the SPS receiver and accesses the DTM to determine a design elevation corresponding to the current location of the machine. Based on the design elevation, the on-board subsystem computes a height command and transmits the height command to at least one of the laser-based subsystems.

Abstract: A system for monitoring location and speed of a vehicle, using a location determination system such as GPS, GLONASS or LORAN and an optional odometer or speedometer, for determining and recording the locations and times at which vehicle speed is less than a threshold speed for at least a threshold time (called a "vehicle arrest event"). Vehicle arrest event locations, times and time intervals are stored and/or printed to provide trip and mileage records and for efficiency monitoring. A vehicle odometer and/or speedometer can also be calibrated and/or corrected using this approach.

Abstract: Methods for estimation of the relative locations (baseline vectors) of two or more GPS signal antennas relative to each other and for estimation of line biases associated with each signal processing channel associated with each GPS signal antenna. Double difference carrier phase signal measurements are formed, using floating integer and fixed integer solutions for the phase integer ambiguities, and baseline vectors between the GPS signal antennas are estimated. Single difference phase integer ambiguities are obtained and approximations for line biases are computed. Single difference carrier phase measurements are used to estimate baseline vectors and line biases, using fixed phase integer ambiguities with the estimated baseline vectors and line biases as initial conditions, and are processed by Kalman filtering or other suitable signal processing. Angular orientation or attitude of a vehicle body on which the GPS signal antennas are placed is determined from the baseline vectors.

Abstract: Methods for GPS-assisted determination of location coordinates of a mobile user or selected position on or adjacent to the Earth's surface with improved accuracy. Elevation readings from an altimeter or barometer are integrated with readings of the GPS-determined elevation coordinate for that location, using Kalman filter techniques, minimum least square techniques, or comparison of certain statistically defined parameters associated with the altimeter and GPS variables, such as the standard deviation of the expected errors in these variables. The resulting elevation coordinate may be a statistical blend or filtered blend of the altimeter value and a GPS-determined value for the elevation coordinate; or this resulting elevation coordinate can be chosen to be one or the other of these values, based upon comparison of time varying statistical parameters corresponding to the altimeter and the GPS.

Abstract: Apparatus for producing a self-authenticating visual image of a selected view, using a digital image forming means, such as a digital camera, together with a position determining system that provides position information, including location and/or angular orientation and/or time of observation at the time a digital image is formed and/or distance from the camera to a selected object. The digital image of the selected view is presented as an array of pixels with associated pixel values. The position information is incorporated in the digital image by altering selected pixel bit values for a selected authentication pattern P of pixels in a chosen subset CS of the pixel array; and this selected pattern may be determined using the position information. The position information may be encrypted, using an encryption key based on position information, and may be stored separate from, or as part of, the digital image.

Abstract: A system for improving the accuracy of location coordinate determined in a survey of a chosen region, using a computer. A grid of spaced apart points is imposed on the region, and a set of survey control points is provided. A "near set" of nearest survey control points is associated with each grid point. For each grid point, a transformation T from a first (global) datum and coordinate system to a second (local) datum and coordinate system is determined that minimizes a collective difference between coordinates of each survey control point in the near set and the corresponding coordinates of that survey control point under the transformation T. For one, two or three coordinates of each grid point, a difference .DELTA. between the coordinate(s) of the grid point in the near set and the corresponding coordinate(s) of that grid point under the transformation T is computed. An interpolation function is determined that approximately matches the coordinate(s) difference .DELTA. at each grid point.

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.

Abstract: Method and apparatus for providing GPS pseudorange correction information over a selected geographic region S with a diameter of up to 300 km with an associated inaccuracy no greater than 5 cm. N spaced apart GPS reference stations (N>4), whose location coordinates (u.sub.n,v.sub.n,w.sub.n) are fixed and are known with high accuracy, are provided within or adjacent to the region R. Each reference station n(n=1, 2, . . . , N) receives GPS signals from at least four common-view GPS satellites, numbered m=1, 2, . . . , M (M.gtoreq.4), computes its own GPS-determined location coordinates, compares these coordinates with its known location coordinates, determines the pseudorange corrections PRC(t;t0;m;n) for its GPS-determined location, and transmits these correction signals to a central station located within or adjacent to the region S. The central station retransmits the pseudorange correction signals throughout the region S.

Abstract: Method and apparatus for monitoring present location of a person ("confinee") who is to be confined to a designated site, which site can have a diameter as small as a few meters or as large as several kilometers. The present location of the confinee is checked at selected time intervals with time periods ranging from one second to thousands of seconds, as desired. The confinee wears a location-determining ("LD") unit that receives electromagnetic signals that contain information allowing determination of the present location of the LD unit, and thus of the confinee, from three or more non-collinear outdoor LD signal sources and from three or more non-collinear indoor LD signal sources. The indoor LD signal sources may be radiowave transmitters. The outdoor LD signal sources may be transmitters for a Loran, Omega, Decca, Tacan, JTIDS Relnav or PLRS or similar ground-based system, or transmitters for a satellite positioning system, such as GPS or GLONASS.

Abstract: A system embodiment of the present invention comprises a fixed and a roving pair of four-observable GPS receivers and a communication link between them for double differencing code and carrier measurements. Carrier phase integer ambiguities are resolved efficiently by searching the simultaneous narrow-lane intersections of both the L1 and L2 wave fronts propagated by the GPS satellites being tracked. External constraint information, such as elevation, is additionally used to speed up integer ambiguity resolution. Data between the reference station and the rover is communicated in compressed form at a regular interval, e.g., once a second at each epoch, and demi-measurements of carrier phase are obtained more frequently, e.g., ten times a second, and used to propagate solutions between epochs.

Abstract: A route exception reporting apparatus is mounted in a mobile shipping vehicle having a predetermined geographic route. The shipping vehicle may be a self-propelled vehicle containing cargo or may also be a separable self-contained shipping container carried on a transportation vehicle. At least a portion of the predetermined route is stored in the apparatus on board the shipping vehicle. The apparatus is provided with a geographic locating means for determining the shipping vehicle location, a comparator means for comparing the shipping vehicle location with at least one point of the predetermined route and a communication means for communicating with a central station. The apparatus is configured to communicate the shipping vehicle location to the central station when the comparator means computes a difference between the shipping vehicle location at a particular point in time and the predetermined route point corresponding with that particular time point which exceeds a predetermined limit.

Abstract: A method and system for determining the location of a mobile position determining system with respect to a destination. In one embodiment, a mobile position determining system has a communication device coupled thereto. Position information of the mobile position determining system is transmitted, via the communication device, to a destination position information database. The destination position information database contains position information of at least one destination. A position comparator then generates range and bearing information indicative of the relative position of the mobile position determining system with respect to the at least one destination. An output device then reports the relative position of the mobile position determining system with respect to the at least one destination to a user of the mobile position determining system.

Abstract: A GPS/radio antenna for receiving a GPS satellite signal and a DGPS radio signal. The GPS/radio antenna includes a GPS antenna using a microstrip antenna element for receiving the GPS signal having GPS location determination information, a radio antenna for receiving a DGPS radio signal in the FM broadcast frequency range having DGPS corrections, an enclosure, and a cable. The GPS/radio antenna may be included in a GPS/DGPS receiver system also including a receiver unit with an FM DGPS receiver for demodulating the DGPS radio signal and providing DGPS corrections, and a differential-ready GPS receiver for providing a differentially-corrected GPS location.

Abstract: A method and apparatus for use in a security system for controlling access to mobile enclosures and cargo containers. Navigtational tracking systems such as LORAN and Global Positioning Systems are used to produce a real time geographic position signal. A programmable data processor is used to compare a preset geographic position signal to the real time geographic position signal. Upon favorable comparison of the real time and preset signals, an enabling signal is produced which permits operation of the security system to gain access to the container.

Abstract: A position-related multi-media presentation system for a vehicle. A position determining system generates position information of a vehicle. The position information is transferred to a multi-media system. The multi-media system presents information related to the position of the vehicle to an occupant of the vehicle. In one embodiment, video information is displayed on a display unit located on the back of a seat of an aircraft. The video information provides views related to features over which the aircraft is flying.

Abstract: The channels of a GPS receiver system are dynamically allocated during acquisition mode to hierarchically chain a slave channel module to a master channel. Each channel circuit includes two correlators, where each correlator receives a digitized received GPS signal and a delayed local PRN reference code signal to provide an output signal to an accumulator. During acquisition, the system provides two correlator channels where each channel includes two correlators for a total of four correllators. A PRN reference code signal is progressively delayed to provide a sequence of progressively delayed PRN reference code signals, where one of the sequence of progressively delayed PRN reference code signals are applied to each of the correlators. Each correlator channel also includes a digital mixer which receives a digitized GPS IF signal and a digital carrier reference signal and which provides the digitized received GPS signal.

Abstract: A GPS receiver having a rapid acquisition of a GPS satellite signal when a normal operational mode is entered after a low power standby mode. The GPS receiver includes an RF section for receiving the GPS satellite signal and providing an GPS IF signal, a correlator section for providing a correlation signal for the correlation between the GPS IF signal and a GPS replica signal, and a microprocessor section for receiving the correlation signal and calculating a geographical location of the GPS receiver. The GPS replica signal is based upon a reference frequency from a reference oscillator and a reference time from a timer. In the standby mode, the operation of the RF section, correlator section, and microprocessor section is inhibited while the reference oscillator and time continue to operate.

Abstract: A GPS receiver having a normal mode to receive GPS satellite signals and to provide location information, and a low power standby mode. A microprocessor system in the GPS receiver causes the GPS receiver to alternate between the normal mode and the low power standby mode in order to reduce the average power consumption in the GPS receiver. In the normal mode a GPS antenna receives GPS satellite signals, the GPS frequency downconverter converts the frequency of the GPS satellite signals to an intermediate frequency, a digital signal processing system processes the intermediate frequency to provide GPS satellite signal correlation information. The microprocessor system processes the correlation information and provides location information to a user. In the standby mode, the operating power is inhibited in the GPS antenna and the GPS frequency downconverter, the system clock is inhibited in the digital processing system, and the microprocessor clock is inhibited in the microprocessor system.