Abstract: A method and apparatus for measuring time related to satellite navigation data messages used with a satellite-based global positioning systems (GPS). A first record of at least a portion of a satellite data message is received at an entity, which is typically a base station of a wireless communication system. The first record is compared with a second record of the same satellite data message (navigation message) received by a GPS receiver. From the comparison, a time is determined indicating when the satellite date message was transmitted (broadcast). The comparison is made in a way that accounts for the only approximate removal of all modulation of the satellite data message by the acquisition and tracking stages of the GPS receiver.

Abstract: An object of the present invention is to inform a person who adjusts the direction of an antenna 70 of the intensity of a signal received by the antenna 70 without connecting or adding special equipment to the antenna 70 or a connection cable 74. The satellite receiver 20 comprises: a received intensity information outputting means 22 for outputting received intensity information describing the intensity of a signal received from the antenna 70; a modulating means 30 for superimposing the received intensity information on a carrier wave; and a superimposing means 40 for superimposing the carrier wave carrying the received intensity information on a connection cable 74.

Abstract: An antenna array system with dynamic signal routing to a set of receivers. A monopulse electronically scanned antenna (ESA) has a plurality of antenna elements divided into subarrays. ESA beam steering phase shifters are associated with the respective subarrays of antenna elements, such that the output signals from the respective antenna elements associated with the respective quadrants are phase shifted and summed to provide respective subarray signals. A monopulse network responsive to the subarray signals provides monopulse outputs to a set of receivers. A beam steering controller provides phase shift commands to the ESA phase shifters to set the phase shift associated with the respective phase shifters of the subarrays. The controller commands the ESA phase shifters to modulate the phase shift of selected quadrants.

Abstract: A low-cost satellite system and method for using it for continuously monitoring near space and providing real-time data, both astronomical and space-environmental, is described and claimed. Low cost is achieved by disposing outwardly facing active and passive detection means aboard telecommunications and other satellites, and providing data from such means to subscribers. The system and method enable practical means to monitor space for approaching foreign bodies, providing high quality information for e.g., underfunded educational institutions while making enhanced use of geostationary orbits, a scarce resource, among other benefits.

Abstract: When a 2-dimensional positioning or 3-dimensional positioning cannot be completed within a predetermined period of time, all currently seized satellites are cancelled and a stored almanac is referred to in order to resume attempts to seize satellites.

Abstract: A computer system includes a communication means for connection to a remote computer and a position determination system for determining the physical position of the computer system. The communications means receives a request from the remote computer for the computer system to provide the physical position of the computer to the remote computer system via the communications means. The request from the remote computer may originate because the computer system has been stolen or mislaid by a user or it may originate because the computer system has inadvertently been allocated the same network identifier as another computer and the physical location of the computer system needs to be known so that the network identifier can be changed.

Abstract: A time signal generation system produces a reference time signal based on the signals transmitted by geostationary satellites, such as the satellites in the Wide Area Augmentation System (WAAS). A receiver in the system includes a directional antenna that is focused on the signals transmitted by the geostationary satellite. The antenna rejects multipath signals, and the receiver thus tracks the satellite signal directly, without having to compensate for multipath distortion. Once the receiver is tracking the code and carrier, the receiver decodes the transmitted data to recover timing information, as well as satellite orbital correction information and an ionospheric model, or table, transmitted by the satellite. The receiver then uses the decoded information and timing pulses provided in synchronism with the transmitted PRN code to produce a corrected timing signal.

Abstract: A circuit module for a phased array (10) incorporates radio frequency (RF) mixers (54a, 54b) connected to an RF splitter/combiner (52) and to in-phase and quadrature RF reference signals. The RF mixers (54a, 54b) are also connected to intermediate frequency (IF) processing circuitry (60 to 68) providing for phase control of RF signals and IF reference signals. In transmission mode, the RF mixer (54a, 54b) receive phase-controlled, digitally synthesised IF signals from clock-activated generators (68a, 68b). Their outputs are combined at the RF splitter/combiner (52) to provide single sideband upconversion of the phase-controlled IF signals. In reception mode, the RF splitter/combiner (52) and the RF mixers (54a, 54b) act as an image rejection mixer circuit in which the phase-controlled IF signals are local oscillator signals. Beamforming is carried out by computer control of the IF phase together with, in the case of reception, analogue or digital summation of output signals from an array of modules (12).

Abstract: A system for directing an antenna for transmission over a two-way satellite network is disclosed. A transceiver is coupled to the antenna; the transceiver transmits and receives signals over the two-way satellite network. A user terminal is coupled to the transceiver and executes an antenna pointing program. The program instructs a user to initially point the antenna to a beacon satellite using predefined pointing values based upon the location of the antenna. The program receives new antenna pointing parameters that are downloaded from a hub over a temporary channel that is established via the beacon satellite. The program displays the new antenna pointing parameters and instructs the user to selectively re-point the antenna based upon the downloaded new antenna pointing parameters.

Abstract: A method, apparatus, and article of manufacture for directing a payload coupled to a spacecraft substantially at a target location is disclosed. The method comprises the steps of determining spacecraft orbital parameters and spacecraft payload attitude parameters; and directing the payload at the target location by applying a spacecraft bus steering law determined at least in part from the orbit and attitude parameters. The apparatus comprises a navigation system for determining spacecraft orbit parameters and spacecraft attitude parameters, and for applying a spacecraft bus steering law to direct the payload substantially at the target location. The spacecraft bus steering law is determined at least in part from the determined spacecraft orbital parameters, the determined spacecraft attitude, and determined payload attitude parameters. In one embodiment, the apparatus includes a payload attitude control system for directing the payload relative to the spacecraft bus.

Abstract: An antenna for scanning beams in only one common angular direction or angular path includes feed elements each providing a component beam and fixed beam combiners for combining the component beams into fixed beams. The fixed beam combiners combine the component beams in a first angular direction to form the fixed beams. Variable beam combiners combine the fixed beams into scanning beams. The variable beam combiners combine the fixed beams into the scanning beams to scan the scanning beams in a second common angular direction.

Abstract: A method for controlling an adaptive antenna array (50) is provided and includes receiving a plurality of signals, each signal including a series of signal data symbols (42) and signal non-data symbols (38, 40) divided into symbol transmission units with the signal non-data symbols (38, 40) disposed among the signal data symbols (42) in each unit and each signal related to the other signals of the plurality of signals as reflections of an original signal. The method also includes separating the signal non-data symbols (38, 40) from the signal data symbols (42), and comparing the signal non-data symbols (38, 40) to a set of known non-data symbols. The method further includes determining a set of weights according to the comparison of the signal non-data symbols (38, 40) to the set of known non-data symbols, the weights to be combined with the signal data values (42) to limit the effect of interference on the signal data symbols (42).

Abstract: A method of mapping (FIG. 10) a characteristic value of a plurality of remote stations (18-24) each having a varying attribute affecting the characteristic value computed according to a predetermined procedure comprising: (a) assigning a plurality of transmission slots to each of the remote stations; (b) determining, by the respective stations, of their characteristic values; (c) initially broadcasting, by the respective stations, of their determined characteristic values in said plurality of transmission slots, said broadcast characteristic value having a first characteristic value resolution; and (d) subsequently broadcasting, by the stations, of their respective characteristic values in said plurality of transmission slots, said subsequent broadcasting having a finer characteristic value resolution relative to said previously broadcasted characteristic value having a first characteristic value resolution.

Abstract: A wireless tracking system consists of a wireless target including a wireless communication system for transmitting a data packet over a communication path, and a locating station for determining a position of the target. The data packet transmitted from the target includes an identification code uniquely associated with the target. The locating station includes a configurable directional antenna, a communication interval processing system, a direction processing system, and a position processing system. The communication interval processing system is in communication with the directional antenna and determines the transmission interval of the transmitted data packet over the communication path. The direction processing system determines the transmission angle of the communication path, and is in communication with the directional antenna for controlling the configuration of the directional antenna so as to facilitate the determination of the transmission angle.

Abstract: An apparatus for an improved antenna tracking system for antennas mounted on an unstable platform. The system comprising a directional antenna, an attitude heading reference system (AHRS) mechanically connected to the at least one directional antenna, a self-scan acquisition and tracking method and an antenna controller connected to the AHRS.

Abstract: In a transmission antenna directivity control apparatus, a reception multi-beam generation section executes weights and combines reception signals from reception array antenna elements using a preset weight coefficient to generate reception multi-beams. A transmission weight coefficient generation section generates, in accordance with detection powers of the reception multi-beams, a transmission weight coefficient for transmission data in correspondence with each of transmission multi-beams corresponding to transmission array antenna elements. A transmission multi-beam generation section multiplies the transmission data by the transmission weight coefficient to generate the transmission multi-beams and supplies them to the corresponding transmission array antenna elements.

Abstract: A method and apparatus of determining the time for a global positioning system receiver is disclosed. Timing signals derived from a communication system, such as cellular phone transmission signals, are received by a GPS receiver and decoded to provide accurate time information. The timing signals may be in the form of synchronized events marked by timing indicators, or as system time information. The timing signals in combination with satellite position signals received by the GPS receiver are used to determine the position of the GPS receiver.

Abstract: A system and method are disclosed that make a navigation system easier to use. According to one aspect of the disclosed system and method, an end-user is permitted to define at least one preferred cities list. The cities included on the preferred cities list are selected by the end-user from all the available cities that are represented in the geographic database used by the navigation system. Thereafter, when the preferred cities list is in use and the end-user operates the navigation system to provide a function that requires that the end-user make a selection of a city, the end-user is presented with a list of the cities from the preferred cities list instead of all the available cities represented in the geographic database used by the navigation system. The preferred cities list is not restricted to cities, but may also include any kinds of places or administrative areas.

Abstract: A phase control device to control an optical control phased array antenna includes a wavelength splitter to split an input optical signal having multiplexed wavelengths corresponding to at least the number of control units of the antenna elements to be controlled for each wavelength, the optical signal, a plurality of phase shifters with different amounts of phase shift to change the phase of the optical signal in accordance with an excitation distribution of antenna elements, an optical switch matrix to assign a required amount of phase shift to an output at each wavelength from the wavelength splitter in accordance with each wavelength to lead it to one of the plurality of phase shifters, and an optical multiplexer to multiplex the outputs from the plurality of phase shifters to output a multiplexed optical signal.

Abstract: A high resolution cross correlation, coherent integration type spectrum analyzer for use in obtaining detailed spectral signatures of subsurface and surface vessels correlates short discontinuous records of the incoming signal with reference signals of known frequencies and accumulates the results to establish cross correlation over a relatively long total record made up of the short discontinuous record segments, with the long combined record being responsible for the high resolution of the system.