Abstract: A method and apparatus are disclosed for determining the position, or change in the position, of a mobile terminal. The terminal has a receiver for receiving the signals from one or more transmission sources at unknown positions and an independent positioning device able to find, when operative, the position of the mobile terminal. The method uses the independent positioning device to measure the position of the mobile terminal at one or more first locations. A respective first set of time or phase offset values of signals received from the transmission sources relative to each other or to a reference in the mobile terminal is measured in the mobile terminal, at each first location.

Abstract: A method of determining the location of a mobile receiver is provided. The method works within a radio system in one or more dimensions, the radio system includes a network of transmitters the positions of which are known. The method comprises the steps of: compiling a list of the signals detected by the receiver, sending said list to a calculation device; constructing a position function which relates to the probability that the receiver is at a given location, which position function has components corresponding to each member of the list, each component including a predetermined probability function that depends on mobile receiver position; and evaluating said position function to determine a position that corresponds to the highest probability of location, and defining that position to be the location of the mobile receiver.

Abstract: To determine whether a mobile terminal of a communications system has moved outside a locale, the terminal measures relative time offsets of signals received by the terminal from transmitters of the network, relative to each other or a reference. At a first time when the terminal is within a given locale, the time of receipt of signals received by the terminal from a plurality of the transmitters relative to a reference or each other are measured to create a first set of receive time offsets. At a second time, a second set of receive time offsets is measured. Change(s) in receive time offsets is/are calculated, and change(s) between the first and second times in transmission time offsets of the signals transmitted by at least one transmitter is/are obtained to determine movement indicators that are compared with threshold valuets to determine whether the mobile terminal has moved outside the locale.

Abstract: A method of processing received satellite radio signals is disclosed in which signals are received the signals from plural satellites through a common antenna. The received signals are digitised to produce a time-series of digitised signal samples and a plurality of replicas representing the signals of each of the plurality of satellites are obtained. At least one sample is selected from each of the replicas and the elements of a register are set equal to the selected replica samples. Thereafter, in turn, for each one of said digitised signal samples, the value of the digitised signal sample is combined with each of the values of the elements of the register to produce corresponding modified values; and the modified values corresponding to each of said register elements are accumulated.

Abstract: A method of and system for calibrating un-calibrated time information within a mobile terminal 101 is disclosed. The terminal has a receiver 203 capable of receiving signals from which calibrated time information carried by a calibrated system (a satellite positioning system) can be extracted, and a receiver 200 capable of receiving signals from which un-calibrated time information carried by an un-calibrated stable system (a cellular communications system) may be extracted. The time offset between calibrated time information extracted from the calibrated system and un-calibrated time information extracted from the un-calibrated stable system is determined at a first terminal position where the signals from the un-calibrated stable system are available, the travel times of the signals from the un-calibrated stable system are known or determined, and the signals from the calibrated system are available.

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: In a terminal 106 having a receiver 202 for receiving the signals from plural transmission sources 101-105 whose positions and transmission time offsets are unknown within the terminal, a method is provided for determining the change in the time (elapsed time) at the terminal between two instants. At a first position of the terminal a first set of measurements, aligned to a first instant, of a signal parameter representative of the time or phase of receipt of said signals from said plural transmission sources relative to one or more of them, or to a reference, or to a terminal clock is obtained. Then at a second position of the terminal a corresponding second set of measurements, aligned to a second instant, of a signal parameter representative of the time or phase of receipt of said signals from said plural transmission sources relative to one or more of them, or to the reference, or to the terminal clock is also obtained.

Abstract: A method of calculating the position or state of motion of one or more terminals is proposed in which each has a receiver capable of making measurements of signals received from one or more transmission sources for use in calculating the unknown position or state of motion of the or each terminal. At least one transmission source has a known directional transmission pattern, and the bearing from one of the receivers of the or each of the transmission source having a known directional transmission pattern is estimated. Weights are assigned to the measurements made by the one receiver, the weights being calculated from the bearing or bearings and the known directional transmission pattern of the transmission sources.

Abstract: A method is described, for use with an SPS mobile terminal receiver 102, of providing a compact assistance vector to initialize 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 initialize a location computation for the SPS mobile terminal receiver 102.

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 of and system for calibrating un-calibrated time information within a mobile terminal 101 is disclosed. The terminal has a receiver 203 capable of receiving signals from which calibrated time information carried by a calibrated system (a satellite positioning system) can be extracted, and a receiver 200 capable of receiving signals from which un-calibrated time information carried by an un-calibrated stable system (a cellular communications system) may be extracted. The time offset between calibrated time information extracted from the calibrated system and un-calibrated time information extracted from the un-calibrated stable system is determined at a first terminal position where the signals from the un-calibrated stable system are available, the travel times of the signals from the un-calibrated stable system are known or determined, and the signals from the calibrated system are available.

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: 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 method and apparatus are described for determining whether a mobile terminal 105 of a communications system has moved outside a locale 107. The terminal is able to measure the relative time offsets of the signals, received by the terminal from transmitters of the network, relative to each other or to a reference. The method includes measuring, at a first time when the terminal is within a given locale, the time of receipt of the signals received by the terminal from a plurality of the transmitters 101-103 relative to a reference or to each other, to create a first set of one or more receive time offsets and storing the first set. At a second time when it is desired to determine whether the mobile terminal has moved outside said locale, the time of receipt of one or more signals received by the terminal 105 from one or more transmitters 101-103 of the plurality of transmitters relative to a reference or to each other is measured, to create a second set of one or more receive time offsets.

Abstract: The present invention sets out to overcome the hearability problem in CDMA communications networks in which positioning services are provided, by using a separate sampling device 204, 205, 206 for each transmitter 201, 202, 203, which sends to the computing device 208 a representation of the signals transmitted only by that transmitter. A cross-correlation of the representation sent back by the mobile terminal 207 with the representation sent back by the sampling device in the brightest transmitter is performed in the computing device 208, and a blurred estimate of that brightest signal is subtracted from a blurred version of the representation sent back by the mobile terminal 207 in order to reduce its effect on the remaining signals as far as possible. The cross-correlation and subtraction steps are iterated until no useful signals remain to be extracted.

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: The invention described relates to a radio positioning system primarily for a mobile telephone network, in which a list of offsets in time, phase, frequency, or derivatives thereof, or their equivalents expressed as offsets in distance or derivatives thereof, of a plurality of transmission source signals, received at a given location, relative to a common reference are generated. Data is acquired from one or more receivers, the positions of which may be known or determined. Such data are offsets in time, phase, frequency, or derivatives thereof, respectively of signals received from the transmission sources relative to a reference source in each receiver or to each other. The acquired data is combined for calculating the list of offsets relative to the common reference.

Abstract: There is described a method of providing a positioning service for plural terminals operating in a communication network which may, for example be a GSM telephone network. The terminals have receivers for receiving signals from transmission sources. In the method measurements of the signals received from one or more of the transmission sources by the receivers are made and the measurements transferred to one or more data nodes. At the data node(s) one or more records of one or more of the measurements are created and at least some of the records are transferred to one or more computing nodes. At the computing node(s) a table of the records transferred to the computing node is maintained and a computation is carried out, using at least part of the table, from which the positions or states of motion or relative positions or relative states of motion of said plural terminals and the transmission time offsets of the transmission sources are extractable.

Abstract: The present invention sets out to overcome the hearability problem in CDMA communications networks in which positioning services are provided, by using a separate sampling device (204, 205, 206) for each transmitter (201, 202, 203), which sends to the computing device (208) a representation of the signals transmitted only by that transmitter. A cross-correlation of the representation sent back by the mobile terminal (207) with the representation sent back by the sampling device in the brightest transmitter is performed in the computing device (208), and an estimate of that brightest signal is subtracted from the representation sent back by the mobile terminal (207) in order to reduce its effect on the remaining signals as far as possible. The cross-correlation and subtraction steps are iterated until no useful signals remain to be extracted.

Abstract: A navigation and/or tracking system has a base station B and a roving receiver R both of which are capable of receiving signals from a plurality of transmission sources T.times.1,T.times.2. A link signal W,W' is passed between the base station and the roving receiver to enable the relative location of the roving receiver to be determined. The apparatus enables the determination of the position of the roving receiver within a space (such as a tunnel T) shielded from receipt of signals from the transmission sources and has equipment P,Q for producing substitute signals, each signal being locked in phase with a signal from a respective one of the transmission sources. A curvilinear transmission element or elements F,F',F", extend within the shielded space T for generating fields in the shielded space. The equipment P,Q propagates at least two of the substitute signals in opposite directions along the curvilinear transmission element or elements for receipt by the roving receiver R.