Abstract: Apparatus and method for determining the present location of a mobile user that carries the apparatus inside or outside buildings and structures within a region R. The apparatus includes a radio location determination (LD) signal module that receives radiowaves from at least three radio LD signal sources, such as FM carrier or subcarrier signals, and an outdoor LD signal module that receives outdoor LD signals from at three other satellite-based or ground-based outdoor LD signal sources, such as GPS, GLONASS or Loran-C signal sources. The radio LD signals and outdoor LD signals are used to (1) determine the location of the radio LD module, (2) determine the location of the outdoor LD module and (3) determine an indicium representing signal strength or signal quality for the radio LD signals and for the outdoor LD signals.

Abstract: Apparatus and method for a location determination and reporting (LDR) system for clandestinely determining and reporting a missing vehicle present location. The vehicle is equipped with a handheld cellular phone unit and controller that are accepted and held by a cellular phone cradle that can include electrical power and/or a location determination (LD) unit to determines the LD unit present location. The cellular phone unit can operate on one cellular channel or on two distinct cellular channels. 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 its present location. The cellular phone does not signal receipt of an incoming call for an initial time period of selected length .DELTA.td, awaiting possible receipt of a location interrogation signal on the first cellular channel.

Abstract: GPS position information is collected and stored in a computer system. The GPS position information includes time-stamps that indicates when the GPS position information was collected. The computer system uses the time stamps to generate an error correction file name for an error correction file that can be used to correct the GPS position information. Using the generated error correction file name, the computer system connects to a file server that stores differential GPS error correction files and copies the needed differential GPS error correction file. The computer system connects to the DGPS file server using the File Transfer Protocol of the global Internet. The computer system then corrects the GPS position information in the computer system using the retrieved DGPS error correction file.

Abstract: A method of recording position data for measuring the position of a ground point during a survey procedure in which satellite signals are used to determine the position of an antenna on a range pole. The pole is moved through non-vertical orientations by an operator so that the antenna position is determined at various points which generally do not lie directly over the ground point. The antenna positions lie on a geometric figure, generally the surface of a sphere which is centered on the ground point and has a radius equal to the length of the pole. Characterizing the sphere by a statistical analysis of the antenna positions either in real time or during post processing, leads to an accurate measurement of the ground point position. The method is preferably enabled by an otherwise standard handheld controller device which operates as part of a roving antenna/receiver station. The satellite signals are preferably derived from the Global Positioning System although other systems may also be used.

Abstract: The timing system for GPS has a week counter that recycles at intervals of about 20 years. The first recycling will occur on Aug. 22, 1999, producing a time ambiguity in GPS signals. The invention employs a count of leap seconds to resolve the ambiguity and extends the useability of GPS in its present format by more than a century.

Abstract: A combined GPS/GLONASS Receiver is disclosed. The GLONASS system of satellites operates at a higher orbit inclination than GPS satellites (64.degree. for GLONASS, 55.degree. for GPS). This leads to GLONASS having better coverage at higher latitudes, e.g. in the State of Alaska or Northern Europe. The combined GPS/GLONASS receiver incorporates this advantage. Another advantage of using the GPS/GLONASS receiver is that GLONASS can become a back up system when the US Government intentionally degrades the GPS system accuracy via Selective Availability (SA). The combined GPS/GLONASS Receiver can receive signals from more satellites and therefore has more resistance to jamming than a single GPS or GLONASS Receiver.

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: A mobile communications system for transmitting or receiving a broadcast signal and designed for mounting on in a vehicle has a transmitter or receiver and one or more antennas electrically connected to the transmitter/receiver. The system is mounted on or in a vehicle so that the transmitter/receiver and the antenna(s) are concealed. The system includes a GPS unit for receiving and processing a GPS and signal a cellular telephone unit for transmitting a fix of the vehicle location (to the police, for example). The system is particularly useful in recovering stolen vehicles and deterring theft.

Abstract: The apparatus and method for estimation and minimization of the residual multipath error signal are disclosed. The reduction of the multipath error signal is achieved by using the weighted or modified tracking. The estimation and minimization of the reduced multipath error signals is achieved by using the generator of additional modified or weighted signals.

Abstract: An antenna for radiating toroidally is disclosed. The antenna may be fabricated to conform with any size of system. The antenna may be placed around an electronics package or a structure to radiate toroidally around the electronics package or structure. The antenna is formed of a strip of copper which includes a number of slots. The slots are disposed longitudinally within the strip of copper such that, upon the application of power to the copper strip, the antenna radiates toroidally. A method for making an antenna that conforms to the size and shape of a particular system is also disclosed.

Abstract: A taximeter system includes a taximeter or trip meter for a truck integrated with an integral GPS receive/computer for providing GPS position and time information. The odometer input pulses to the taximeter are accurately calibrated by using GPS position, velocity, and time information to generate corrected odometer pulses which are provided to the odometer input terminal of the taximeter. The GPS system is integrated into the taximeter for calibrating and cross checking of input odometer pulses to provide reliable, consistent distance measurements by the taximeter. The integrated taximeter and GPS system provided according to the invention uses GPS position, velocity, and time information to produce incontrovertibly accurate corrected, odometer input pulses and GPS time signals for the taximeter to precisely compute elapsed time and distance traveled. Dead reckoning operation of the system is available when the GPS receiver has service outages.

Abstract: A method and apparatus for automatic event detection and processing is provided. A positioning system receiver includes a position measurement device and a logging device. The position measurement device is configured to receive and process signals from a positioning system. The logging device is coupled to the position measurement device for recording data received from the position measurement device. The logging device records the data at a current logging rate. The positioning system receiver detects an event via an external sensor or with reference to satellite data, for example. In response to the event, the logging device automatically modifies data logging processing such as the current logging rate. Additionally, to allow a post processing system to go backwards in time relative to the event, the current logging rate may be increased for a predetermined amount of time preceding the occurrence of the event.

Abstract: A system for determining exact solutions of the pseudorange equations obtained from measurements of location determination (LD) signals received from N LD signal sources by a mobile LD station. The LD signal sources may be part of a GPS, a GLONASS, LEO or any other satellite-based or ground-based LD system, such as Loran. Squares of differences of the pseudorange equations are subtracted from each other to produce N-1 linear relations between the unknown location coordinates x, y and z and the receiver clock offset b. These linear relations are used in one or more squares of pseudorange equations to produce a quadratic equation in b, or in x, y or z. A physically realistic solution b is found and used to determine the remaining unknown coordinates (x,y,z). No iteration or approximation is required. For N.gtoreq.5, the approach extends to situations where the clock offset varies with time. For N.gtoreq.

Abstract: Method and apparatus for prediction or estimation of fuel or energy consumption by a vehicle over a chosen trip route, where the route includes a plurality of road segments. Fuel consumption over each road segment is estimated, using information on one or more of the following variables: representative altitude of the road segment; representative slope of the road segment; estimated vehicle average speed along the road segment; length of the road segment; condition of the road segment; condition of the vehicle tires; expected vehicle traffic density along the road segment; applicable constraints on vehicle operation along the road segment; expected ambient weather conditions along the road segment; vehicle accessories that will be used; and vehicle driver profile information. Weather conditions enroute, such as local wind speed and direction, can be measured and used to enhance accuracy of predicted fuel consumption.

Abstract: A parallel feed network antenna and a method for making a parallel feed network antenna having improved consistency in antenna pattern and improved reliability and which is easier and cheaper to manufacture is disclosed. In one embodiment of the present invention, a housing containing raised surfaces defining a channel is formed using plastic injection molding techniques. A layer of conductive material such as copper is selectively deposited over the surface of the housing so as to cover the channels. The upper surface of the housing is then removed until the conductive material which overlies the raised surfaces adjoining the channel is removed so as to form a microstrip. The patch antenna are then attached to the housing and electrically coupled to the microstrip to complete the antenna.

Abstract: The effect of the multipath distortions on the carrier phase measurements is reduced by using the weighted correlation functions. The generators of both periodic and dynamic weighted functions are used. The apparatus and method employing generators of such weighted functions can comprise the standard correlators and/or the weighted function correlators.

Abstract: A handheld survey device includes a Global Positioning System (GPS) receiver for receiving position information, a pointer to point to the location to be measured, a measuring device to measure the distance between the handheld device and the location to be measured and a level and heading device to determine the level and heading of the handheld device. A processor located within the handheld device computes the position of the location using the position information, the distance measured between the handheld device and the location, and the level and heading information. The position computed meets the stringent accuracy requirements dictated by survey applications without the use of a range pole.

Abstract: Method and apparatus for formation of an autocorrelation difference function of an incoming digital signal, with bit transition interval .lambda..tau..sub.chip, that reduces the effects of presence of a multipath signal in an incoming composite signal. First and second autocorrelation functions AC(.tau.;E;qE) and AC(.tau.;L;qL) are formed with respective first and second selected time shift values .tau.=t.sub.E and .tau.=t.sub.L, which replicate an estimate of an autocorrelation function AC(.tau.;P;qP) at an intermediate time shift value .tau.=t.sub.P that satisfies t.sub.E <t.sub.P <t.sub.L with t.sub.L -t.sub.E <2 .DELTA..tau..sub.chip, and which depend upon one or more parameters qE and qL, respectively. Independently chosen, non-uniform weighting functions w1(t;qE) and w2(t;qL) are used for formation of the respective autocorrelation functions AC(.tau.;E;qE) and AC(.tau.;L;qL) that depend upon one or more parameters qE and qL.

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.