Abstract: A cellular communication system is provided for transmitting a large number of highly directive personalized communication beams throughout an original geographic cell of the cellular communication system. The system advantageously utilizes a phased array antenna positioned at a center location of the cell in conjunction with a spread spectrum communications method which includes code division multiple access techniques for increasing user capacity. Each of the communication beams represents user signals assigned to specific users located within the original geographic cell and are adjustable in the user's directions. The total number of the communication beams may equal the number of users within the cell. An omnidirectional antenna is positioned in close proximity to the center location of the cell for transmitting and receiving an omnidirectional communication beam for communication with users located within approximately one half of a mile of the center location.

Abstract: A global positioning system receiver includes an inbound signal terminal to receive an inbound global positioning system signal having an inbound PRN code from a global positing system signal source. A local PRN code generator is configured to generate a local PRN code. A discriminator is coupled to the inbound signal terminal and to the local PRN code generator and configured to compare the inbound signal and the local PRN code and to generate a discriminator signal containing a positive portion and a negative portion. A processor is coupled to the discriminator and configured to receive the discriminator signal to process the discriminator signal to determine a bit code and to determine a distance from the global positing system signal source based on said bit code.

Abstract: The disclosure pertains to receivers for positioning by satellite. To reduce the harmful effects of the paths reflected on the GPS measurement of position which should take account only of the path of the radiofrequency signals in direct line of sight, a method is proposed enabling the elimination of the influence of the multiple paths by simple extrapolation computation. Measurements are made by correlation with four pseudo-random codes E1, E2, L1, L2 that are replicas of a code received from a satellite. A first set of measurements of correlation energy values and of time received is carried out with the codes E1, L1 corresponding to an advance and a delay d with respect to a punctual code and a second set of measurements is carried out the codes E2, L2 corresponding to an advance and a delay k.d (k being different from 1 and 0). By linear extrapolation, a deduction is made therefrom of the measurements for k=0, which no corresponds to the case where the multiple paths have no effect.

Abstract: A method and apparatus for controlling an antenna and a tracking antenna system using them. A rate sensor detects the angular rate of the vehicle turning. On the basis of the detected value, an error correction circuit determines the steering angle of the antenna. If it is judged from the determined angle that the vehicle is not turning or only slightly turning, a motor driving circuit suspends driving of a motor and at the same time a linear actuator locks a major gear. If it is judged that an accumulated error of a control target which is determined on the basis of the output of the rate sensor is not negligible, the error correction circuit starts a closed-loop control on the basis of a receiving signal level. In such a manner, the power consumption in the motor can be reduced.

Abstract: A positional information storage and retrieval system includes a positional detection unit transmitting positional information of at least one subject moving within an operational environment of the system, a plurality of receiver/transmitter units and a processor unit. Coordinate information of the receiver/transmitter units is received by the positional information unit and used to determine the positional information according to triangulation or other techniques embodied within the positional detection unit. The positional information is transmitted to the receiver/transmitter units which, in turn, transmit the positional information to the processor unit. A method for designing such a system includes selecting operational frequencies of the receiver/transmitter units and positioning the receiver/transmitter units throughout the operational environment such that distortion and attenuation of the positional information are minimized.

Abstract: An improved navigation satellite receiver for tracking individual spread-spectrum frequency spectral lines with a microwave receiver antenna to receive signals from orbiting navigation satellites, a downconverter to produce in-phase and quadrature (I and Q) signals from the received satellite signals, and a digital processing system for frequency and phase locking numeric controlled oscillators (NCO) to the carrier and code of the satellite signals. The improvement comprises at least one spectral line tracker connected to receive the (I and Q) signals and including a spectral line numeric controlled oscillator (NCO) connected to a spectral line mixer that drives a spectral line code correlator. The spectral line NCO is frequency-aided to frequency lock on a spectral line from a value obtained from the carrier NCO.

Abstract: A method and apparatus for synthesizing a stable reference signal of a desired frequency within a spread spectrum receiver is disclosed herein. The spread spectrum receiver is designed for use in conjunction with a global positioning system (GPS) receiver, and operates to receive broadcast differential GPS correction information. The present frequency synthesis technique contemplates generating a sequence of timing signals within the GPS receiver on the basis of GPS satellite signals received thereby, and providing the timing signals to the signal receiver. Within the signal receiver, the signal cycles of a local oscillator occurring between ones of the timing signals are counted. The frequency of the local oscillator is then determined by dividing the counted cycles of the local oscillator by one of the known time intervals. The determined frequency of output signals produced by the local oscillator is then scaled so as necessary to produce the reference signal of desired frequency.

Abstract: In a wireless communication network a method for locating and tracking status of a plurality of radio ports comprises the steps of: determining a coordinate position of one of the plurality of radio ports; and transmitting the coordinate position to a control center. The method can further comprise the step of removably-interfacing a GPS receiver to one of the plurality of radio ports. Transmitting the coordinate position to the control center can utilize a wired connection. Additionally, the coordinate position can be stored at the control center. The coordinate position is integrated into a map of the plurality of radio ports. A nonresponsive radio port can be identified by a corresponding coordinate position and the wireless network traffic can be routed appropriately.

Abstract: This invention relates to automatic direction finding methods and systems for an electromagnetic or acoustic signal source by utilizing the concept of adaptive nulling of a narrow or wideband signal received by one sensor from the same signal received by the other, along with appropriate adjustments, in a two-sensors-interferometer. Plurality of sensors can be used to measure two orthogonal angles of arrival of a signal. Inventive methods and devices permit singling out a particular signal of interest among others by allowing a frequency tuning and selective amplification of the particular signal of interest without destroying the differential phase or time delay between the signals received by the sensors that determine the angle measurement. A high degree of signal cancellation during the adaptive nulling process permits a correspondingly high degree of accuracy and resolution for the angle measurement and also permits a relatively short baseline for the interferometer.

Abstract: The system and method of allowing the civilian GPS receivers to utilize the satellite transmitted P(Y) code signal without requiring the detailed P(Y) code to be revealed inside the receiver are disclosed. This is done by using the W code generator inside the civilian receiver, by integrating the W code signal across the W period, and by delaying the integrated signal to protect against the possible spoofing attack. The generator of the integrated and delayed W code signal is placed inside the tamper-proof container.

Abstract: In a cellular type communication system a sector antenna 12 provides coverage of a sector with a relatively low receive gain. A multi-beam antenna 20 covers the same sector with a plurality of narrower beams 21', 22', 23' and 24' providing higher gain. A multi-beam antenna system 10 provides higher gain operation by selecting the one of the narrower beams 21', 22', 23' or 24' currently providing best reception of a signal transmitted by a user and coupling that selected beam to a system receiver 18. Beam selection is accomplished by sequentially coupling each narrow beam to a microprocessor based control unit 40 and storing samples of user signals as received in each narrow beam on a continuing repetitive basis. The stored samples are then analyzed in order to select the beam currently providing best reception.

Abstract: A method of reducing the effects of interference on a radio receiver having access to multiple transmission sources including the steps of monitoring the signals received from all available sources, utilising information derived from the received signals from each source to compute the most likely frequency band of the interference, determining from said most likely frequency in conjunction with known ephemeris for the receiver and the current Doppler shift of the source signals which sources are least susceptible to interference at said most likely frequency, and passing the identities of said least susceptible sources to the receiver acquisition software.

Abstract: A beam electronically steers, in real time, a multielement sensor array at radio frequencies. A sensor array is configured in one embodiment with orthogonal loops and orthogonal dipole elements. Each loop and dipole combination generates a polarized output signal which is routed, via a connection matrix, to an equal number of signal splitters. The resulting modal patterns are then routed to networks having quad hybrids and digitally user-controllable vector modulators. The signals outputted from the quad hybrids and the vector modulators of each of the networks are inputted to separate combiners. The signals outputted from the separate combiners of the networks are then recombined in combiners. The signals outputted from these combiners define the azimuth around the Z-axis, the elevation around the Y-axis, and the elevation around the X-axis, respectively.

Abstract: An enhanced system for calculating the Z-Axis, or relative height or altitude, of a radio beacon. The present invention uses a barometric pressure sensing device co-located with the radio emitter to transmit data representing relative altitude. To further enhance the Z-Axis determination, one or several barometric sensors, located at known heights, are positioned around the city to provide real time barometric data. This real time data is used to form a differential correction factor which is compared to the to the time varying barometric sensor co-located with the radio emitter, thereby yielding Z-Axis accuracies of up to one (1) foot. Since the altitude essentially becomes a "known", this information can also be used in the least squares fit algorithm to enhance the X and Y determination as well.

Abstract: A positioning method for a mobile station in the radio coverage area of a satellite entails determining the instantaneous distance between the satellite and the mobile station. The instantaneous elevation angle .phi. of the satellite is then calculated from the instantaneous distance, the altitude of the satellite and the radius of the Earth. The Doppler shift .delta. is then determined, after which the angle .theta. between the projections onto the surface of the Earth of the track of the satellite and a straight line segment passing through the satellite and the mobile station is calculated from the Doppler shift .delta. and the instantaneous elevation angle .phi.. The location of the mobile station is then determined from the instantaneous distance, the instantaneous elevation angle .phi. and the angle .theta..

Abstract: A special mobile radio mobile, vehicle or personal location system is described where the system operates to locate any one of a the transmitters in an SMR system. The present invention operates by identifying the received signals, removing the modulation information to reconstruct a demodulated carrier and analyzing the carrier signals for multipath distortion. The multipath disruptions are removed to calculate the true incident angle of the transmitted signal at a base station. A plurality of base stations are used to simultaneously calculate the incident angle of the transmitted SMR signal and a central location calculates the most probable location of the transmitter based upon triangulation. The incident angle of the transmitted SMR signal at each base station is performed by calculating the phase differences of the incoming voice signal with phase ambiguity minimized by using a plurality of dipole antennas spaced at an irregular distance to eliminate phase ambiguity error.

Abstract: An existing TDRSS satellite communication system is incorporated, together with low-power ground-based remote transceivers of special design, and additional beam forming and steering elements at the ground terminals, to make possible digital communication between low power field transceivers and satellite ground terminals. The satellite communication system transmits to its ground terminals a composite signal, comprising amplified, phase-coherent signals received by an array of broad-coverage antennas on the satellite. The field transceiver transmits a pseudonoise coded signal spread across all or a portion of the satellite's receive bandwidth. At the ground terminal, the downlinked composite signal is processed by a beamformer to define a narrow, high-gain beam between the satellite and low-power transceiver. Signal processing gain and beamformer gain in combination serve to elevate the received, demodulated signals well above the noise level at the receiver.

Abstract: A location determination system and method in which mobile receiver units are in an area of at least three fixed commercial television stations, each television station broadcasting standard television signals, including horizontal, vertical and chrominance burst synchronizing signals. The standard television signals from selected ones of said television station are received at the mobile receiver unit and the times of arrival synchronizing signals of the selected ones of the television stations, respectively, are measured to produce mobile receiver unit signals corresponding thereto. A fixed reference station receives the television signals and detects any frequency and wavelength drift in the standard television signals from each of the fixed commercial television stations, respectively, and produces reference receiver correction signals.

Abstract: A bi-static radar configuration measures the direct time-of-flight of a transmitted RF pulse and is capable of measuring this time-of-flight with a jitter on the order of about one pico-second, or about 0.01 inch of free space distance for an electromagnetic pulse over a range of about one to ten feet. A transmitter transmits a sequence of electromagnetic pulses in response to a transmit timing signal, and a receiver samples the sequence of electromagnetic pulses with controlled timing in response to a receive timing signal, and generates a sample signal in response to the samples. A timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The receive timing signal causes the receiver to sample the sequence of electromagnetic pulses such that the time between transmission of pulses in the sequence and sampling by the receiver sweeps over a range of delays.

Abstract: A ground unit capable of being carried on the back of a member of the armed orces is used in conjunction with a marker beacon. The ground unit detects and identifies the signals from the marker beacon and is also capable of indicating the direction in which the marker beacon is located. For identification purposes, a received signal at the ground unit from the beacon is checked with a known identification code signal inserted in the ground unit by the user. Upon detection of the signal the user can determine the direction to the marker beacon by scanning with a hand-held antenna system. Visual and audio information is provided to the user.