Abstract: The invention provides a method of combining satellite positioning system signals and position information derived from such signals in a mobile terminal, when these are available at a first location, with cellular communication signals and a method, system and apparatus for determining the approximate position information for the said mobile terminal when SPS signals are not available at a second location. The approximate position is determined in the mobile terminal only using a position difference vector derived from the cellular communication signals using time offsets and associated time-tags in a method based on the observed time difference of arrival. The computations of cellular position and position difference information are made within the network infrastructure. The invention provides for the security of the user as only position difference information is communicated over the air interface, or transmission time offset measurements which require non-transmitted information to determine a solution.

Abstract: A navigation system is described which includes a mobile terminal 100 which has a transmission source receiver 204 for receiving the signals from one or more unsynchronised terrestrial transmission sources 102-105 and a satellite positioning receiver 200 for receiving signals from the satellite or satellites 107-110 of a satellite positioning system. The terminal also has a clock 208. A processor 209 is arranged to acquire a measurement vector having a list of values, each value representing a measurement made by a receiver 200,204, and the terminal clock's bias. It computes a state vector representing the current state of the system, using a previously-determined state vector, the measurement vector, and a dynamic model in order to derive a dynamic navigation solution.

Abstract: A method of associating a universal time with time of arrival information of an identified component of a signal at a terminal of a radio positioning system is disclosed. In the method a marker signal with an associated universal time tag is obtained from a timing device (or the marker signal is obtained from an independent oscillator and a universal time tag assigned to the marker signal), and the time or phase relationship between the marker signal (or between the time of arrival information of said identified component respectively) and the oscillator is measured. The time of arrival information of said identified component relative to the oscillator is determined and the universal time corresponding to the time of arrival information of said identified component is calculated from said universal time tag and said measured time or phase relationship, before the calculated universal time is associated with said time of arrival information.

Abstract: A method is described, for use with an SPS mobile terminal receiver 102, of providing a compact assistance vector to initialise and constrain the computation of the terminal's location within a region of validity. The compact assistance vector is provided to a computing node 108 able also to obtain measurements from a mobile terminal satellite positioning system receiver within said region. For a known reference point 104 within the region, the range or ranges from the reference point to one or more satellites 101 of the satellite positioning system are obtained. The range or ranges are represented by a number or numbers of ranging code repeat intervals in a limited resolution format. The compact assistance vector is created from the representation or representations of ranging code repeat intervals and transferred to the computing node 108. The compact assistance vector can then be used to initialise a location computation for the SPS mobile terminal receiver 102.

Abstract: The invention provides a method of combining satellite positioning system signals and position information derived from such signals in a mobile terminal, when these are available at a first location, with cellular communication signals and a method, system and apparatus for determining the approximate position information for the said mobile terminal when SPS signals are not available at a second location. The approximate position is determined in the mobile terminal only using a position difference vector derived from the cellular communication signals using time offsets in a method based on the observed time difference of arrival. The computations of cellular position and position difference information are made within the network infrastructure. The invention provides for the security of the user as only position difference information is communicated over the air interface, or transmission time offset measurements which require non-transmitted information to determine a solution.

Abstract: Positioning apparatus for use in a moving vehicle includes circuitry arranged to process signals received from GPS satellites, and to provide signals in response thereto from which the position of the apparatus can be calculated at a remote station. The apparatus provides, for each satellite in view, carrier frequency estimation signals, samples of the carrier signals and code tracking signals to a data transmission device, which modulates the signals onto a carrier prior to transmission to the remote station. A carrier loop reconstruction device and a location processor in the remote station cooperate to determine the location of the positioning apparatus. A memory device at the remote station may record the signals received from the vehicle over a period of time, for subsequent carrier loop reconstruction and location determination.

Abstract: Positioning apparatus for use in a moving vehicle includes circuitry arranged to process signals received from GPS satellites, and to provide signals in response thereto from which the position of the apparatus can be calculated at a remote station. The apparatus provides, for each satellite in view, carrier frequency estimation signals, samples of the carrier signals and code tracking signals to a data transmission device, which modulates the signals onto a carrier prior to transmission to the remote station. A carrier loop reconstruction device and a location processor in the remote station cooperate to determine the location of the positioning apparatus. A memory device at the remote station may record the signals received from the vehicle over a period of time, for subsequent carrier loop reconstruction and location determination.

Abstract: A satellite-based positioning system includes at least one mobile station (11) and a terrestrial station (10), which may be a cellular telephone base station and is arranged to receive ephemeris data from each in-view positioning satellite. The ephemeris data is processed in a processor (14) to provide processed data which defines the satellite orbit in Cartesian form. Processed data is transmitted over a short message service channel to each mobile receiver (11), which includes also a positioning system receiver (25). The mobile receiver (11) is able to determine its position from the processed data and from signals received from positioning satellites with reduced processing, and thus reduced power consumption and/or time, than previous mobile receivers. The terrestrial station (10) may operate as a reference receiver which modifies the processed data to correct for errors in the ephemeris data and/or atmospheric propagation effects and/or the effects of selective availability.