Abstract: A system using GPS data for locating a person requesting a support. The system includes a mobile terminal carried by a person to acquire the GPS data from GPS satellites and transmits the same upon a request by the person to a message center where the GPS data is processed to calculate the person(s position. The mobile terminal simply acquires the GPS data which is invalid for calculation of the position if the request is made where the GPS satellite is not available. For successfully locating the person's position, the mobile terminal acquires the GPS data regularly at different times in accordance with a time schedule and stores the time-series sets of the GPS data which are transmitted together with a current GPS data acquired in response to the support request, thereby giving the latest available position of the person if the current GPS data is found invalid.

Abstract: The tracking of moving vehicles over long distances without emitting illumination signals is accomplished with a narrowband passive differential tracking system. Instead of Providing especially designed radar transmitters in a bistatic radar system, illuminators of opportunity (which may include UHF and VHF television station) are selected by their geographic locations so that they are in proximity to a moving target. The Doppler-shifted target reflected signals from the illuminators of opportunity are converted into digital data and combined with the independently derived initial target location and used to update the target's position and velocity by correlating the Doppler-shift with geographic coordinates. The correlation can be accomplished with a tracking algorithm which was designed for use in data processing of the signal processing system of the narrowband passive position tracking system.

Abstract: A method and apparatus that allows correlations between a selected parameter and the error in a pseudo range measurement to be exploited. A database is established in which the amount of error estimated for particular pseudo range measurements to a beacon is maintained. Clusters are defined. Each cluster is associated with a range of values for the selected parameter. Pseudo range measurements are then associated with a particular cluster based upon the value of the selected parameter at the time (or proximate to the time) the pseudo range measurement was taken. As more estimates of the pseudo range measurements are made, the size of the clusters (i.e., the range of values of the selected parameter) can be reduced. Due to the correlation between the selected parameter and the errors in the pseudo range measurements, reducing the size of the clusters reduces the variance of the error estimates. The mean value of the error estimates is used to correct the error in future pseudo range measurements.

Abstract: Methods and apparatuses for deriving an approximate Doppler for a satellite positioning system (SPS) receiver from an approximate location which is obtained from a cellular communication system information source. In one embodiment, an approximate location of the SPS receiver is derived from the information source and this approximation location is used to determine approximate Dopplers to a plurality of SPS satellites at a given time. The approximate Dopplers are then used to reduce processing time in either determining pseudoranges to the SPS satellites or acquiring signals from the SPS satellites. In another aspect of the invention, a reference signal is used to provide a local oscillator signal which is used to acquire SPS signals in an SPS receiver. This reference signal is extracted from a data signal modulated on a carrier frequency.

Abstract: The invention provides a method and apparatus for determining the direction of a signal such as for example a received radio signal in a cellular mobile communication system. At lest two antenna arrays (10, 12) are connected to associated processors (14, 16) for extracting the desired signal and two independent direction of arrival estimates are determined in associated direction estimators (18, 20). A similarity testing unit (22) determines the direction of arrival and the accuracy of this estimate from the difference between the two estimates. A feature of the invention is controlling the beam form of a downlink signal in response to the direction estimate and the determined accuracy.

Abstract: A method and apparatus for computing GPS receiver position without using absolute time information transmitted by the satellite or by an alternative source of timing available at the GPS receiver. The GPS receiver is contained in an integrated receiver that also includes a wireless communication transceiver, but does not have access to an accurate source of absolute time information. The wireless transceiver communicates through a wireless network to a server. The GPS receiver measures satellite pseudoranges and uses the wireless communication transceiver to send the pseudoranges to the server. The server fits the pseudoranges to a mathematical model in which the GPS receiver position and the absolute time are unknown parameters. The server then computes a position and absolute time that best fit the model, thus yielding the correct position for the GPS receiver, and the absolute time at which the pseudorange measurements were made.

Abstract: The invention relates to a method of locating a jammer (14) of a satellite telecommunications system (10). To locate the jammer, at least two of the following three measurements are performed: a measurement of the difference between the instant of arrival at the telecommunications satellite and at a detection satellite (16) of signals transmitted at the same time by the jammer (14), the detection satellite being used solely for detection purposes; a measurement of the difference between the frequencies received by the telecommunications satellite and by the detection satellite, for a signal transmitted by the jammer; and an interferometric measurement of the angle between a direction associated with the detection satellite and the straight line between said satellite and the jammer (14).

Abstract: The angle at which a multipath finger produced by a digital radio communication source arrives at an antenna array can be estimated using an uplink weight vector associated with the multipath finger. Due a characteristic of uplink weight vectors used in antenna arrays having a shift invariance structure, the estimate of the angle can be calculated based on the uplink weight vector.

Abstract: Methods and apparatuses which use satellite position system (SPS) reference receivers. In one example of the invention, a plurality of SPS reference receivers, such as Global Positioning System (GPS) reference receivers, each having a known position, are dispersed over a geographical region. Each of the SPS reference receivers transmits into a communication network, a representation of at least a portion of a satellite navigation message, such as satellite ephemeris data, received from SPS satellites in view of the particular SPS reference receiver. A plurality of digital processing systems, such as a first and a second digital processing systems, are coupled to the communication network to receive the satellite ephemeris data which is transmitted through the communication network.

Abstract: A method of attenuating an unwanted electric field radiation caused by electrostatic induction on an internal conductive coating of a cathode ray tube by a pulse voltage generated by a deflection circuit is provided. A reverse pulse voltage, which is reverse in polarity to the pulse voltage of the deflection circuit, is impressed on an external conductive coating of the cathode ray tube and electrostatic induction induces a pulse voltage on the internal conductive coating which is reverse in polarity to a pulse voltage of the deflection yoke induce on the internal conductive coating through an electrostatic capacitance existing between the internal conductive coating and the external conductive coating so that an unwanted electric field radiation from the front screen of a cathode ray tube is attenuated.

Abstract: A method for determining the geolocation of an emitter using sensors located at a single or multiple platforms is disclosed. Generally, the method includes the steps of receiving a first measurement set relative to a first emitter, the first measurement set including angle of arrival, time difference of arrival and/or terrain height/altitude measurements, receiving a first location guess or estimate for the first emitter, and determining at least a second location estimate using at least one of a batch least squares analysis and a Kalman filter analysis.

Abstract: A signal/sensor automatically sends a wireless signal upon sensing that a vehicle has been parked. There is also provided a locator for determining a current location and storing the current location upon receiving the wireless signal. The current location may be determined by accessing a GPS service through a GPS receiver. The current location may further be refined by accessing a DGPS service through a DGPS receiver or a wireless communication device. The locator also comprises a compass and a relative direction and bearing indicator. Upon receiving a user request, the locator determines a new current location and determines a current heading with the compass. Next, a relative direction and bearing to the parked vehicle may be determined by a processor on board the locator or by accessing a remote server through the wireless communication device. Last, the relative bearing and direction to the parked vehicle is conveyed to the user through the indicator.

Abstract: In an adaptive array antenna, the phase-shifted amount of one of a plurality of phase shifters is changed to a value obtained by increasing a currently set phase-shifted amount by a predetermined angle, and then, to a value obtained by decreasing the currently set phase-shifted amount by a predetermined angle. The variation in strength of a received signal combined at this time is detected by a signal strength detector, and a partial differential coefficient of a performance function with respect to the phase-shifted amount is derived using only the detected variation in strength of the received signal. Thus, the phase control based on the partial differential coefficient of the performance function with respect to the phase-shifted amount is carried out with a simple circuit construction without the need of signals of each antenna element.

Abstract: A precision carrier frequency signal for calibrating a local oscillator of a GPS receiver which is used to acquire GPS signals. The precision carrier frequency signal is used to calibrate the local oscillator such that the output of the local oscillator, which is used to acquire GPS signals, is modified by a reference signal generated from the precision carrier frequency signal. The GPS receiver locks to this precision carrier frequency signal and generates the reference signal. In another aspect of the invention, satellite almanac data is transmitted to a remote GPS receiver unit from a basestation via a communication link. The remote GPS receiver unit uses this satellite almanac data to determine approximate Doppler data for satellites in view of the remote GPS receiver unit.

Abstract: An apparatus and method determining angle-of-arrival of a received radio frequency signal, and apparatus and method for calibrating the angle-of-arrival determining apparatus.

Abstract: A system and method for automated differential correction processing of field data in a global positioning system (GPS). In one embodiment, the present invention retrieves GPS field data collected by one or more GPS receivers from a storage device, and then automatically selects the most appropriate differential correction scheme to generate a solution without user intervention. More specifically, the present invention executes a code-based correction scheme to generate a code-based solution for the field data. Next, the present invention examines the field data to determine whether a carrier phase correction is applicable. If the field data supports carrier phase correction, the present invention generates a carrier phase solution, compares it with the code-based solution, and returns the more accurate of the two solutions as the final result. If the field data does not support a carrier phase correction, the present invention returns the code-based solution as the final result.

Abstract: Provided herein is a radio wave receiving apparatus including a signal processing circuit comprising: a means for the Fourier transform in respect of azimuth of an electric field signal outputted from an antenna receiving circuit; a means for the Fourier transform in respect of azimuth of the antenna pattern of an antenna; a means for dividing the Fourier transform signal derived from the electric field signal by the antenna pattern Fourier transform signal; a low-pass filter for subjecting the divided signal to low-pass filtering; a means for extracting exponential function components of the output signal of the low-pass filter; a means for extending the band of the output signal of the low-pass filter beyond the cut-off frequency of the low-pass filter by using the exponential function components; and a means for subjecting the band-extended signal to Fourier inverse transform in respect of azimuth, the signal after the Fourier inverse transform being outputted as a final antenna output.

Abstract: A portable type distance/speed meter is designed for measuring a travel distance and a travel speed when a user walks, or runs, while realizing a correct average speed calculation in response to GPS electromagnetic waves receiving conditions.

Abstract: A bistatic passive radar system is used in conjunction with a host transmitter that is a determinable distance D from the radar system for determining the distance D and for displaying video images of a selected target, the position of the radar system and the position of the transmitter on a display. The invention is characterized by a system and method of using the display to determine the slant range S and the altitude H of the selected target relative to the position of the radar system. Three alternative embodiments of the invention are disclosed.

Abstract: An antenna test range uses a direct spread-spectrum based test signal to effectively electronically reject all unwanted signals that may be present in the test range, and thereby allow both main beam and off-axis performance of the antenna to be completely and accurately measured. For increased dynamic range, the test signal comprises a carrier signal that is sequentially modulated with low rate, respectively different, direct spreading PN sequences applied to a cascaded plurality of N mixer stages through successive ones of which the carrier signal is coupled. The plurality of PN spreading sequences are mutually offset in time by a fraction of a chip, and thereby produce, at an output of an Nth mixer stage, a direct sequence spread spectrum carrier signal having its energy spread out over a bandwidth that is N times the spreading bandwidth of an individual one of the PN spreading sequences.