Itt Manufacturing Enterprises, Inc.

Stanford Telecommunications, Inc.

Other

Lloyd Engelbrecht

Leonard Schuchman

Ronald C Bruno

Aaron Weinberg

Positioning system for locating a mobile body comprising a plurality of earth based spread spectrum (SS) broadcasting stations arranged geographically in a cellular pattern. Each SS broadcasting station include a modulator providing a channel signal structure which is substantially orthogonal with respect to adjacent stations in the cellular pattern, each channel signal including navigation beacon data including a unique beacon identification, station latitude and longitude, time_slot and phase characterizations and selected parameters of adjacent stations. In one embodiment, each modulator provides a chirped SS signal in which the navigation beacon is a frequency tone that is repeatedly swept over a selected frequency band for each station. In a further embodiment, each modulator provides a GPS like direct sequence SS signal in which the navigation beacon is a PN coded broadcast. A receiver on the mobile body receives the SS signals from at least three of the SS broadcasting stations and determines the location thereof. A fourth SS broadcasting station provides altitude CPS satellite signals can be used for timing control.

Cellular positioning system (CPS)

A cellular telephone system having three or more cell sites with each cell site having a source of cellular communication signals and an RF transmitter and antenna for broadcasting the cellular communication signals. A direct sequence spread spectrum waveform carrying navigation signals is embedded in the cellular communication signals, including controlling the signal strength of the navigation signals so that the combined energy of the navigation signals from all cell sites at any location is at least a predetermined energy level below the energy level of the cellular communication signals. Each cell site includes timing for timing the operation of a GPS receiver. An RF signpost system comprising a plurality of low powered RF broadcast stations, one each at a plurality of scattered geographic locations, each low powered RF broadcast station broadcasting a direct sequence spread spectrum digital RF waveform and means to modulate the digital RF waveform with location information identifying the geographic locations, respectively.

Position enhanced communication system including system for embedding CDMA navigation beacons under the communications signals of a wireless communication system

A monitoring and location system comprising a service center from which movement to and from a prescribed local area and a prescribed wide area is to be monitored. Each member of a class being monitored is provided with a personal RF transponder unit (RFTU). Each RF transponder unit has a digital electronic identification number (DEIN) embedded therein for transmission by RF upon request. RF transceiver interrogation units define specific egress/ingress zones for the prescribed areas. Each interrogation unit being connected to the service center to god signal (1) when an RFTU has egressed or ingressed a prescribed area and (2) the DEIN embedded therein. The RF transceiver interrogation units can determine distance and bearing to a given RFTU and DEIN. When there are a plurality of cell sites encompassing the prescribed areas, an RF transceiver interrogation unit at each of the cell sites, respectively, are connected to the service center. Each RFTU has an emergency signalling component which, when activated, causes a range and bearing measurement to that RFTU to be made and sent to the service center for action.

Personal location system

A method of avoiding near-far interference problems in a cellular ray of navigation signal beacons having selected CDMA or GPS-like navigation signals. The navigation signals from adjacent navigation signal beacons are pulsed so that adjacent navigation signal beacons do not broadcast navigation signals simultaneously and the multiple frequencies are coordinated in a time divisional multiplex manner. In another aspect, the near-far interference problem is avoided by using multiple frequencies in time division multiplexing and coordinating the use of the multiple frequencies and the time division multiplexing to assure avoidance of the near-far interference problem.

Method of avoiding near-far interference problems in an array of

A cellular telephone communication system has at least one base station and a plurality of remote mobile stations in which both base and mobile stations have RF transceivers which communicate with each other using periodically repeated pulse sequence epochs whose time patterns are known at both transmitting and receiving station. Each mobile station transceiver, during normal operation, establishes and maintains synchronization between the start of a received pulse epoch at the mobile station and a subsequent beginning of a responsive transmitted pulse epoch. An agile antenna system is located at the base station and includes at least one scanning antenna spaced a selected distance from a central reference point. The scanning antenna is effectively rotated relative to the central reference point and adapted to receive RF transmissions from a selected mobile station, and a direction or bearing detection processor is connected to antenna systems for detecting from received RF transmissions from the selected mobile station the bearing to the selected mobile station from the base station. The bearing sensing processor is one selected from amplitude sensing, phase sensing or frequency sensing or a combination of these sensing principles. A range measuring processor circuit also at the base station measures the time interval from the start of the base station's transmitted pulse epoch to the start of a pulse epoch subsequently received from the selected mobile station and derives range to the selected mobile station therefrom.

Phase agile antenna for use in position determination

Base station and system modifications to a digital cellular telephone system that measures location of a mobile station from its normal transmissions, and can forward the measured position to that station or some other authorized caller or service on the communication network. Range measurement is enabled without modification of mobile station equipment because of the synchronization between received pulse epochs and transmitted ones that are required for normal operation in digital telephony. Range measurement is made at a base station currently in contact with the mobile station by measuring the time interval from the start of its own transmitted pulse epoch to the start of a pulse epoch subsequently received from the mobile station, then dividing that time interval by twice the velocity of radio waves. Direction from the base station is determined, in a preferred embodiment, by use of a planar phase steered antenna array synchronized to pulse sequences from the mobile station.

Positioning system for CDMA/PCS communications system

Positioning system for locating a mobile body comprising a plurality of earth based spread spectrum (SS) broadcasting stations arranged geographically in a cellular pattern. Each SS broadcasting station include a modulator providing a channel signal structure which is substantially orthogonal with respect to adjacent stations in the cellular pattern, each channel signal including navigation beacon data including a unique beacon identification, station latitude and longitude, time.sub.-- slot and phase characterizations and selected parameters of adjacent stations. In one embodiment, each modulator provides a chirped SS signal in which the navigation beacon is a frequency tone that is repeatedly swept over a selected frequency band for each station. In a further embodiment, each modulator provides a GPS like direct sequence SS signal in which the navigation beacon is a PN coded broadcast. A receiver on the mobile body receives the SS signals from at least three of the SS broadcasting stations and determines the location thereof. A fourth SS broadcasting station provides altitude. CPS satellite signals can be used for timing control.

A digital broadcast system, comprising a master radio broadcast station located at a main predetermined location for formatting and broadcasting a plurality of channels of digitized program data in a spread spectrum, time and frequency hopping waveform to remote mobile and stationary receivers. A plurality of relatively low power range extension radio broadcast stations are provided, each said range extension station being located in selected areas and, each range extension station being adapted to receive and store one or more channels of program information from the master station. A separate program distribution system coupling the received and store of each range extension radio broadcast station with the master radio broadcast station, said separate distribution system, including, for each range extension station at least one path selected form satellite, microwave, fiber-optic, coaxial cable and telephone paths, for coupling one or more channels of program information to each range extension station. The channels of digital data re-broadcast from each of the range extension radio broadcast stations is synchronized with broadcasts from the master radio broadcast station such that a mobile receiver traveling between edges of reception of two or more low power range extension radio broadcast stations does not evidence interference therebetween.

Digital broadcast system

A cellular telephone system having three or more cell sites with each cell site having a source of cellular communication signals and an RF transmitter and antenna for broadcasting the cellular communication signals. A direct sequence spread spectrum waveform carrying navigation signals is embedded in the cellular communication signals, including controlling the signal strength of the navigation signals so that the combined energy of the navigation signals from all cell sites at any location is at least a predetermined energy level below the energy level of the cellular communication signals. Each cell site includes timing for timing the operation of a GPS receiver. An RF signpost system comprising a plurality of low powered RF broadcast stations, one each at a plurality of scattered geographic locations, each low powered RF broadcast station broadcasting a direct sequence spread spectrum digital RF waveform and a modulator to modulate the digital RF waveform with location information identifying the geographic locations, respectively.

Position enhanced communication system including system for embedding

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. A processor, which may be at the reference station or at the mobile receiver units, computes the location of the mobile receiver units from the mobile receiver unit signals and the reference receiver correction signals.

Location determination system and method using television broadcast

The present invention relates to a no outage GPS/AM position finding system wherein a GPS system having a plurality of satellites transmits time and location data over radio frequency signals to enable a mobile GPS receiver station on the ground to determine its position, and a cellular telephone is carried with the mobile GPS receiver, traveling in range of a plurality of conventional ground based amplitude modulated (AM) transmitters for transmitting AM signals. Each mobile GPS receiver station includes phase detection means for simultaneously receiving a predetermined number of the AM signals, and measuring the changes in phase of each of the AM signals as the mobile GPS receiver travels, and deriving therefrom an AM position signal. A reference station for receiving the GPS and AM signals provides correction signals via a cellular telephone network which receives and transmits the correction signals to the mobile GPS receiver station. The last accurate GPS position signal is used for resolving any ambiguities in the AM radio position signal and to accommodate the lack of synchronization in the AM transmitters. The reference station measures the frequency and wavelength variations in the AM signals and conveys same to the mobile GPS receiver station by the cellular telephone. The AM position signal is activated upon detecting outages or blockages in the GPS signals.

Growing community of inventors

Reston, VA, United States of America

Lloyd Engelbrecht