Abstract: Apparatus for determining and broadcasting the approximate location of a person or other object that has fallen overboard from a boat or other structure into a body of water. The apparatus includes a floatable object that is thrown into the water near the overboard person/object to broadcast the location of the object and the nearby overboard person. The floatable object includes: an activatable Satellite Positioning System (SPS) receiver/processor and antenna to receive SPS signals from two or more SPS satellites; an activatable location transmitter and transmitter interface to receive the SPS-determined location information from the SPS receiver/processor; a power supply to supply power to the SPS receiver/processor and the location transmitter; and activation means to activate the SPS receiver/processor and location transmitter.

Abstract: Method and apparatus for indicating and allowing a traveler to follow a chosen route from an origin point to a destination point on the Earth's surface, using a portable Satellite Positioning System and audible or visual information presentation means. Initially, the traveler positions a map or chart with the intended route thereon on a light-sensitive table and traces each segment of the route with a pressure-sensitive light pen. Information on each segment and the locations of its endpoints is entered in a microprocessor. Coded information shown on the map itself is entered into the microprocessor, using a bar code reader or similar device. Along the route, the traveler carries the microprocessor and a portable Satellite Positioning System (SPS) antenna and receiver/processor, connected to the microprocessor.

Abstract: A method and apparatus are disclosed for characterizing multipath-induced distortions in the autocorrelation function of a correlation receiver in order to reduce effects of these multipath-induced distortions on the accuracy of detecting the time of arrival of a received signal. The magnitude of the multipath-induced errors adversely affecting the shape of the autocorrelation function is estimated in real time, for example, through the use of secondary scanning correlators whose time base is independent of a typical receiver's detection-oriented correlators. This error is subtracted from the detection-oriented correlator's timing, thereby yielding a more accurate autocorrelation function.

Abstract: An embodiment of the present invention includes a GPS receiver capable of concurrently tracking up to eight GPS satellites. The GPS receiver comprises computer-implemented methods for parallel search, split search and precomputation. The parallel search method causes the apparent Doppler frequency spectrum to be sectioned into several segments and a first GPS satellite signal is searched for in parallel in each of the segments. When the first GPS fix is not found after a predetermined time has expired, a split search is begun.

Abstract: Mobile system apparatus for accurately determining the location of a designated object, spaced apart from the apparatus, without having to approach the designated object. The invention uses a Satellite Positioning System (SATPS), such as GPS or GLONASS, to determine the SATPS location of a first reference SATPS station, whose location is known with high accuracy, and of a second mobile SATPS station. The second mobile SATPS station uses two SATPS signal antennas, spaced apart a known distance but arbitrarily oriented. SATPS antennas at the first and second SATPS stations each receive SATPS signals from a plurality of SATPS satellites that can be used to determine the location of each antenna. The location of each SATPS antenna may be determined using differential corrections for the location of the first SATPS station antenna. The locations of the two SATPS signal antennas at the second SATPS station define a baseline for purposes of determination angular orientation.

Abstract: Apparatus for visually displaying simultaneously on one screen two variables that characterize the path followed by a land, marine or airborne vessel with reference to a preselected or ideal path that extends from a beginning point to an ending point.

Abstract: An embodiment of the present invention combines, on a single integrated circuit, a first bipolar transistor in a common-emitter configuration capacitively coupled to a second bipolar transistor in a common-base configuration, together with a capacitive input coupling for a single-ended input and directly-coupled collector outputs for a differential-output for driving successive differential-input and differential-output emitter-coupled transistor pairs for multiple stages of amplifier gain.

Abstract: A method for accurately determining the position of a roving receiver positioned on or above the Earth's surface, relative to the position of a reference receiver whose position is known with sufficient accuracy, using measurements of signal phase transmitted at one or more carrier frequencies and received from each of four or more satellites in a Satellite Positioning System (SPS). Phase double differences are formed, using the reference and roving receivers and any two satellites drawn from four or more satellites, using phase information obtained from either or both of the two carrier signal frequencies. Phase correction information, in the form of estimates of integer wavelength ambiguities, is then obtained from two sets of ambiguity estimates computed with the roving receiver antenna in each of two specified positions, with the reference receiver antenna lying between and being collinear with the two roving receiver-antenna positions.

Abstract: A method for transmitting and verifying the accuracy of a software program, expressed as a stream of J bits.. A first forward error correction error coding, detection and correction (ECDC) procedure is applied to the program, where the first ECDC procedure is expressible as a stream of K1 error coding bits plus L1 additional bits representing the procedure for determining the values of the K1 bits and for detecting the presence of and correcting an error in the original stream of J bits plus the K1 error coding bits, as received by a recipient. A second ECDC procedure is then applied to the K1+L1 bits used in the first ECDC program, where the second ECDC procedure is expressible as a stream of K2 error coding bits plus L2 additional bits representing the procedure for determining the values of the K2 bits and for detecting the presence of and correcting an error in the (K1+L1}bits that represent the first ECDC procedure.

Abstract: Method and apparatus for reporting of an emergency event experienced by a marine vessel, an airborne vessel or by an occupant of the vessel. The present vessel position, accurate to within a few tens of meters, and (optionally) the vessel velocity and local air quality, is determined at an ordered sequence of times, using a position-determining Global Positioning System, such as the Navstar system or the GLONASS system. If an emergency occurs on the vessel, the approximate present position and time of occurrence of this event is broadcast on one or more of the mobile communication or emergency radiowave bands. Optionally, the type of emergency event that has occurred, drawn from a predetermined list of such types, is also broadcast by a vessel in distress, for receipt by an emergency response facility or by another vessel that can respond to a call for assistance. Optionally, vessel velocity heading and/or vessel position quality of fix information is also broadcast by a vessel in distress.

Abstract: An embodiment of the present invention is a system for automatically pointing a directional antenna. The system comprises two GPS antennas mounted at horizontally opposed extremities of the directional antenna, the placement is such that the GPS antennas lie on a line having a normal vector approximately parallel to a boresight of the directional antenna. The outputs from the GPS antennas are downconverted to a measurement frequency and differentially phase compared for each of a plurality of radio visible GPS satellites. A measurement controller that receives the phase comparisons. A navigation computer receives measurements from the measurement controller and uses a microprocessor to calculate the GPS latitude and longitude and the attitude angles of the pair of GPS antennas. A servo points the directional antenna at a particular target communications satellite, based on the computed azimuth, elevation, latitude, and longitude, as provided by the navigation computer.

Abstract: Cordless antenna apparatus for determination of the location of an observer and/or of the time of observation by use of a Satellite Positioning System (SPS), such as the Global Positioning System or the Global Orbiting Navigational Satellite System. In each embodiment, the apparatus includes a Smart Antenna device and a display unit, connected by a wireless link. In a first embodiment, the Smart Antenna device includes: an SPS antenna to receive the SPS signals; an SPS signal frequency downconverter; an SPS signal processor to receive antenna output signals and to determine at least one of the present location of the SPS antenna or the time of observation; a transmitter to receive processor output signals and transmit these signals to the display unit; and a power supply.

Abstract: An embodiment of the present invention relates to a worldwide network of differential GPS reference stations (NDGPS) that continually track the entire GPS satellite constellation and provide interpolations of reference station corrections tailored for particular user locations between the reference stations Each reference station takes real-time ionospheric measurements with codeless cross-correlating dual-frequency carrier GPS receivers and computes real-time orbit ephemerides independently. An absolute pseudorange correction (PRC) is defined for each satellite as a function of a particular user's location. A map of the function is constructed, with "iso-PRC" contours. The network measures the PRCs at a few points, so-called reference stations and constructs an iso-PRC map for each satellite. Corrections are interpolated for each user's site on a subscription basis.

Abstract: Method and apparatus for providing precise universal time coordination or synchronization for each of a plurality of N vehicles, numbered consecutively i=1, 2, . . ., N (N.gtoreq.2) that move within a selected geographic region and that communicate by radiowaves with one or more base stations located within or adjacent to the selected region. Each vehicle is provided with a sequence of Satellite Positioning System (SPS) signals, with a sequence of SPS timing signals, and with a SPS signal transceiver/processor that receives the SPS signals and SPS timing signals and determines the present location of the vehicle and the time the vehicle location determination is made. One or more base stations broadcast a sequence of base station timing signals that are received by each vehicle.

Abstract: Apparatus for determining the distance, accurate to within an error of no more than 1 mm, from a first position to a second position. The apparatus includes a distance marker that includes a first strip having a sequence of uniformly spaced light-reflecting (or light-transmitting) regions in one embodiment and includes a second strip having a sequence of uniformly spaced light-reflecting (or light-transmitting) regions, the two strips being positioned parallel and adjacent to each other with the positions of the light-reflecting (or light-transmitting) regions of the first strip being translated relative to the positions of the light-reflecting (or light-transmitting) regions of the second strip by a fixed translation distance. The apparatus also includes a light sensor positioned adjacent to the strip to sense each such light-reflecting region (or light-transmitting region) and/or each non-reflecting region (or non-transmitting region) as that region moves past the light sensor.

Abstract: An embodiment of the present invention is a communications system for multiple users sharing the same maximal length code (MLC) in a code position modulation multiple access environment. A 1023 chip length code is transmitted with reference to an independent coordinated time source. The code repeats every time after 1023 chips have been transmitted. The MLC will begin each time period with the first through 1023.sup.rd chip, depending on the data to be sent and the identity of the user transmitting it. The chips belong to the MLC that were not sent at the beginning of a time period are sent at the end to complete the MLC each time period in a wrap around fashion. Each time period can be aribtrarily divided into subsections embracing, for example, sixteen chip times. When so divided, more than sixty subsections are possible from one 1023 chip MLC. Respective users are each assigned a subsection.

Abstract: Apparatus that is carried on a land vehicle, a marine vehicle or vessel, or an airborne vehicle or vessel for notifying others that a vehicle accident or other abnormal situation has occurred and for notifying others of the location of the vehicle at the time of the accident. The vehicle carries an distance measuring system (DMS) signal antenna and receiver/processor that receives DMS-type signals from one or more DMS signal broadcasters and determines the present position of the vehicle, plus an activatable transmitter. The vehicle also carries an abnormality sensing means that senses the occurrence of an accident or other abnormal situation involving the vehicle or a vehicle occupant. When an abnormal situation is sensed, the abnormality sensing means automatically activates the transmitter, which then communicates the fact that an abnormal situation has occurred and the location of the vehicle at the time the event occurred.

Abstract: An embodiment of the present invention is a single-chip GPS receiver front-end comprising a radio frequency amplifier, a voltage-controlled oscillator operating at a first local oscillator frequency, a divide by seven and one-half counter for deriving a second local oscillator frequency from the first and a first and second mixer. The local oscillator frequency is mid-way between two carrier frequencies of interest that may be received by the radio frequency amplifier and the first mixer produces a first intermediate frequency. The second local oscillator frequency is then beat with the first intermediate frequency in the second mixer to produce a second intermediate frequency. A dual-conversion super heterodyne configuration is therefore employed in which the first and second local oscillator frequencies are derived from a single oscillator and the first local oscillator frequency is seven and one-half times the second local oscillator frequency.