Abstract: The invention relates to a determining the position of a mobile receiver 4 in a digital telephone network positioning system. A first receiver 3 is at a known location and others are mobile. The method involves transmitting signals from a plurality of sources 1, the transmission signals having a format at least a portion of which has predetermined values or a portion of which is repeated. The time offset of the transmission signals received at each receiver 4,5 from a transmission source 1 relative to a reference clock of each receiver is determined by generating a reference signal locked to the reference clock. The reference signal has a similar format to the transmission signals and includes a portion identical to the predetermined values or repeated portion of the received signal and compares the received transmission signal and the reference signal.

Abstract: The invention provides a method of estimating the time offsets between signals transmitted by plural transmitters of a communications network and received by a receiver attached to a terminal. In the method a section of a representation of the signals from the plural transmitters received by the receiver at the terminal (a “terminal section”) is created as are a first section of a representation of the signal transmitted by a first of said transmitters and a second section of a representation of the signal transmitted by a second of said transmitters. Each of the first and second sections overlaps in time with the terminal section. Using the first section, the second section and a set of signal parameters, including initial estimates of the time offsets between the first section and the terminal section and between the second section and the terminal section, a model of a section of a representation of the composite signal received by the receiver from the first and second transmitters is created.

Abstract: A location measurement unit 401 for a radio location measuring system has two or more coupling devices 404,405 for picking up the signals from a plurality of base transceiver stations (BTSs) of a cellular radio communication system. A switching device 510, is connected to the coupling devices, for switching between the signals picked up by the coupling devices and/or one/two or more receivers 510, 610-613 are connected to respective coupling devices, for receiving the signals picked up by the coupling devices. A processor 512, 614 is connected to the or each receiver, for processing the signals output by the receiver. A communications link 513, 615 is connected to the processor, for transferring the processed signals to a calculation node 514.

Abstract: The invention concerns a method of determining the position or change in position or state of motion of a receiver or receivers, the position or change in position or state of motion of which is or are not already known, in a network of transmission sources some or all of whose positions are known. At a first time, the relative offsets in time, phase, frequency, or derivatives thereof with respect to each other, or with respect to a reference source, of the signals received by a first receiver from a plurality of the transmission sources are measured. At a selected second time, the respective offsets of the signals received by the same or a second receiver, whose position or state of motion is not already known, from the plurality of the transmission sources are measured.

Abstract: A method is disclosed for finding the position of a mobile radio-frequency transceiver in a communication system. A network of at least two unsynchronized base stations is arranged to transmit and receive signals to and from at least one mobile radio frequency transceiver. A reference receiver located at a known distance from the base stations measures the times of arrival of signals transmitted from the base stations. Using the known distances and measured times, a determination is made of the relative time offsets of transmission from each base station. The determined relative time offsets are used to calculate the position of the mobile transceiver in the network area using hyperbolic positioning techniques. A number of other enhancements including the use of Doppler, carrier information, and direction of arrival to improve the performance of mobile telephone-based positioning systems are also described.

Abstract: The invention relates to a position determining system, for receiving digital telephone signals transmitted by a number of transmission sources BTS. The system has a pair of receiving stations, CBU and CRU, one at a known position O and another on a roving object R; a position determining processor CPP; and means for passing a link signal, L1 and L2, from each of the receiving stations to the position determining processor, the link signal containing information about the signals received at the receiving station from the transmission sources. Each of the receiving stations is arranged to receive the signals from the respective transmission sources substantially simultaneously. The position determining processor is arranged to compare the information received from the one receiving station with the information received at the other receiving station, and to determine the time delay between the respective signals received at both receiving stations in order to determine the position of the roving object.

Abstract: The invention concerns a method of finding the position of a mobile radio-frequency transceiver in a communications system. A network of at least two unsynchronized base stations arranged to transmit/receive signals to at least one mobile-radio frequency transceiver; a reference receiver located at a known distance from the base stations and including measuring means to measure the times of arrival of signals transmitted from the base stations; determination means to use the known distances and measured times to determine the relative time offsets of transmissions from each base station; and location means to use the determined relative time offsets to calculate the position of a mobile transceiver in the network area using hyperbolic positioning techniques. A number of other enhancements to positioning systems relating to the usage of Doppler, carrier information, direction of arrival to improve the performance of mobile telephone-based positioning systems are also described.

Abstract: The invention relates to a position determining system, for receiving digital telephone signals transmitted by a number of transmission sources BTS. The system has a pair of receiving stations, CBU and CRU, one at a known position O and another on a roving object R; a position determining processor CPP; and means for passing a link signal, L1 and L2, from each of the receiving stations to the position determining processor, the link signal containing information about the signals received at the receiving station from the transmission sources. Each of the receiving stations is arranged to receive the signals from the respective transmission sources substantially simultaneously. The position determining processor is arranged to compare the information received from the one receiving station with the information received at the other receiving station, and to determining the time delay between the respective signals received at both receiving stations in order to determine the position of the roving object.