Abstract: A low power GPS receiver, including an RF section to receive a GPS signal having information for determining a location fix and to issue an IF signal, a correlator system to correlate an internal replica signal to the IF signal and to issue a correlation signal including location and signal strength information, a microprocessor system to receive the correlation signal, to read the signal strength, and to provide a location fix, and an on/off modulator to receive a duty cycle factor from the microprocessor system and to on/off modulate the operating power to the RF section to provide a minimum signal strength for a valid location fix. The off time duration of the modulation is shorter than the time duration of the interval used to correlate the IF signal enabling the GPS receiver to continue to correlate the IF signal and to provide the location fixes while the RF section operating power is reduced by the duty cycle factor.

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: An apparatus combining a handheld, electronic video game device, a location determination receiver, an electronic map and/or electronic yellow pages, and geocoding. The apparatus provides a user with his location and locations of map features and/or yellow page addresses proximate to his location. The handheld, electronic video game display displays the user's location and a map and/or yellow pages and hosts a memory cartridge that includes software for a user interface, for maps and/or yellow pages database, and for geocoding. The apparatus benefits from the high manufacturing and sales volumes of existing handheld games devices.

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: 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: The mobile station designed for the mobile differential dynamic surveying and targeting is disclosed. The mobile station includes a targeting device for acquiring the coordinates and the image of the designated remote target object. The mobile station further includes a SATPS based differential position-angular determination system capable of determining the coordinates of the mobile station and the angular coordinates of the normal vector to the mobile station. The mobile station receives the differential corrections from the differential station and transmits the data and image information to the third station.

Abstract: A GPS navigation receiver with a data output port for communicating a position estimate frame-by-frame and time codes in SMPTE format. The conventional date and time sentence output of the GPS navigation receiver is combined with a highly-accurate one pulse-per-second (.+-.one microsecond) to form a time-keeping base for the time code output. A data-logger records the position estimates with their corresponding time in time code format frame-by-frame in a database. The recorded position estimates are then used in special-effects post-production to direct the special-effects animation, modeling kinetics, etc., in a composite, final film or video.

Abstract: A system for assuring the location integrity of a decryption chip used to receive and decrypt encrypted signals ES received from an encrypted signal source. The decryption chip operates in association with a licensed signal receiver and is licensed for use at a selected site or location L.sub.i and is positioned adjacent to a Satellite Positioning System (SATPS) antenna and receiver/processor that determine the present location L of this antenna. If the SATPS-determined location L is within a region R(L.sub.i ;d.sub.i), centered at the location L.sub.i and having a selected diameter d.sub.i, and if the signal ES is associated with a channel that is authorized for reception by this signal receiver, the deception chip is enabled, and the signal ES is decrypted for audible or visual display on the signal receiver. Otherwise, the decryption chip does not decrypt the incoming signal ES. The licensed site location L.sub.

Abstract: Apparatus for determining the present location of, or time of observation by, an observer in the vicinity of the Earth's surface. The apparatus provides a Satellite Positioning System (SATPS), such as GPS or GLONASS, in a portable device or card that is built to the I.E.E.E. PC/104 Standard, which is a variation of the I.E.E.E. P996 Standard for personal computer buses. The PC/104/SATPS Card includes an SATPS antenna to receive (and frequency downconvert, if necessary) SATPS signals from one or more SATPS satellites, a microprocessor programmed to receive the SATPS signals from the antenna and to perform calculations to determine the spatial location of the antenna and/or the time of observation by the antenna. The PC/104/SATPS Card has a buffer and a format translator to compensate for SATPS signal latency and for differences in SATPS signal arrival rate and PC/104 signal processing rate and/or to translate signals from SATPS format to whatever format the microprocessor uses.

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 an internally generated replica signal, and a microprocessor section for receiving the correlation signal and calculating a geographical location of the GPS receiver. The replica signal is based upon a reference frequency from a reference oscillator and a reference time of arrival (TOA) from a timer. In order to increase acquisition speed, the microprocessor section provides the correlator section with an initial frequency adjustment and an initial TOA adjustment to correct for drift in the reference frequency during the standby mode.

Abstract: Apparatus and method for a location determination and reporting (LDR) system for clandestinely determining and reporting a missing vehicle present location. The vehicle may be stationary or moving and may be anywhere within reach of a cellular central station to which the location is reported. The vehicle is equipped with a location determination (LD) unit, including an LD signal antenna and receiver/processor (preferably hidden on the vehicle) that determines the LD antenna present location, a specially configured cellular telephone, and a controller. When the vehicle is reported missing, the central station interrogates the vehicle LDR system to determine the vehicle present location. A location interrogation signal is transmitted, commanding the LD unit to transmit the LD antenna present location. The vehicle phone does not signal an incoming call for an initial time period of selected length .DELTA.t.sub.d, awaiting possible receipt of a location interrogation signal.

Abstract: Method and apparatus for using a plurality of correlators to improve an estimate of direct signal arrival time by identifying features of a correlation function at and adjacent to the correlation peak. In a first embodiment, the errors in location of the center point of a correlation function R(.tau.), formed by the incoming composite signal and a stored copy of the expected signal, are assumed to be strongly correlated for narrow sample spacing and wide sample spacing of the correlation function. In a second embodiment, multipath signal strengths and phases are estimated, using multiple sampling of the correlation function R(.tau.). This approach assumes that path delays of the direct signal and of the multipath signals can be determined separately.

Abstract: A navigation wristwear device comprises a GPS receiver fully disposed in a wrist watch type housing. A transparent microwave patch antenna is patterned of indium-tin-oxide on sapphire in front of an LCD time, position and velocity display. A bezel provides a protective window. A low-noise amplifier, downconversion, code processing and navigation processing are all provided on a single integrated circuit. Photovoltaic solar cells to each side of the LCD help keep a battery charged.

Abstract: Apparatus and method for providing timing control signals for operation of an engine and other devices on a vehicle and/or operation of telecommunications equipment and/or computer equipment on the vehicle. A Satellite Positioning System (SATPS) antenna and receiver/processor receive and process signals from three or more SATPS satellites and determine and issue SATPS-determined timing pulses and time signals that indicate the time associated with each timing pulse. The pulse-to-pulse time separation .DELTA.t.sub.pp of these timing pulses is adjusted to provide a separation approximately equal to a selected pulse separation .DELTA.t.sub.incr. Alternatively, a supplementary timing device provides a sequence of timing pulses with pulse-to-pulse spacing that is adjustable by varying an environmental parameter .theta., such as temperature or electrical field, for this timing device.

Abstract: An antenna system for a navigation satellite receiver tuned to dual-frequency transmissions from orbiting navigation satellites. Respective L1 and L2 microwave patch antennas are mounted flat and adjacent to one another on a common ceramic substrate and have their centers grounded to a groundplane on the opposite side of the substrate with vias. Each patch antenna is connected to a respective near-by low-noise amplifier. The low-noise amplifiers are both connected to a signal combiner and a final radio frequency amplifier for down feed to a navigation satellite receiver. A direct current signal from the navigation satellite receiver is used on the down-feed to selectively control which one of the two low-noise amplifiers is to operate. Thus one coaxial down-feed supplies power to the low-noise amplifiers and provides for the selection between the L1 and L2 carrier frequencies on the down-feed.

Abstract: A cellular telephone system embodiment of the present invention comprises a combination global positioning system (GPS) receiver and cellular transceiver and a data processing facility for converting latitude, longitude, velocity and bearing information provided by the GPS receiver into meaningful descriptors that are spoken with a speech synthesizer back to the cellular transceiver or an outsider who calls in an inquiry to a "1-900" service.

Abstract: The optimum SPS receiver is described that allows to optimize the demodulation of the unknown W-code generated by the Global Positioning System (GPS). The assumed timing and the spectrum structure of W-code are used for selecting the optimum digital filter that optimizes the signal-to-noise (STN) ratio of the received satellite signals.

Abstract: An improved single or dual-frequency navigation satellite receiver that can directly re-acquire P-code code-phase after a brief loss of P-code tracking. A digital signal processor (DSP) writes its current position fixes to a non-volatile memory. The DSP also updates a clock that keeps a running estimate of precise global positioning system time. When P-code code-phase is lost, it is re-acquired by reading the clock back in, adjusting for its drift, reading in the last position fix from the non-volatile memory, and then beginning an advanced P-code code-phase search based on such head start information.

Abstract: A system for selecting an optimal transformation T(G2;G1) between a first ellipsoid E1 (e.g., WGS 84) in a first global coordinate system G1, relative to which the survey measurements are made, and a second ellipsoid E2 in a second global coordinate system G2. A set of location coordinates (x'.sub.m,2, y'.sub.m,2,z'.sub.m,2) for M previously-surveyed locations, numbered m=1, . . . , M, and a set of location coordinates (x'.sub.n,1, y'.sub.n,1,z'.sub.n,1) for N presently-surveyed locations, numbered n=1, . . . , N (M.ltoreq.N) are provided, where the first M presently-surveyed locations coincide with the M previously-surveyed locations. The transformation is chosen so that the images of the location coordinates (x'.sub.n,1,y'.sub.n,1, z'.sub.n,1) for n=1, . . . , M under T(G2;G1) are as close as possible to the corresponding location coordinates (x'.sub.m,2,y'.sub.m,2, z'.sub.m,2) for m=1, . . . , M. Given an ellipsoid and a selected survey plane .tau.

Abstract: The optimal design of the SPS Receiver is disclosed. The optimal SPS Receiver includes the digital filter with adjustable characteristics in each digital processing channel. The optimal design of the SPS Receiver is achieved by adjusting the filter characteristics of each digital filter to match the observed spectrum of the unknown W code satellite signals. The matching operation can be performed for each satellite channel with its own secret W code signal.