Abstract: A method of determining the position of a mobile unit (MS1) having a GPS receiver (24) is disclosed. The method comprising the steps of measuring mobile unit pseudoranges at the mobile unit (MS1) using the GPS receiver (24); providing reference pseudoranges corresponding to a reference location situated remote from the mobile unit (BS1); and determining the position of the mobile unit (MS1) relative to the reference location (BS1) as a function of both the reference pseudoranges and the mobile unit pseudoranges.

Abstract: A method of despreading a GPS spread spectrum signal received at a mobile unit MS1 with assistance from a base station BS1 is disclosed comprising the steps of (a) receiving and despreading GPS signals at the base station and deriving GPS signal information therefrom; (b) estimating the location of the mobile unit; (c) modifying the GPS signal information so as reflect the GPS signal characteristics as would be observed at the estimated location of the mobile unit; (d) transmitting the GPS signal information from the base station to the mobile unit; (e) generating replica signals containing PRN codes corresponding to those of the GPS signal using the modified GPS signal information; and (f) performing a correlation of the GPS signal and the replica signals in order to acquire the GPS signal.

Abstract: The present invention provides for a method of receiving a signal spread over a frequency range, and in particular a direct sequence spread spectrum signals including the step of employing a Fast Fourier Transform (FFT) in the Doppler search. In particular, the invention relates to the receipt of spread spectrum signals such as those transmitted as part of a GPS system.

Abstract: GPS receiver (1) is disclosed together a mobile unit especially in the form of a mobile cellular telephone (30) incorporating the same. The GPS receiver (1) comprises a GPS signal antenna (10) for receiving externally transmitted GPS signals; an analogue-to-digital converter (11) coupled to the antenna for sampling the received GPS signals; a memory (12) for storing the GPS signal samples; and a digital GPS signal processor (13, 14) for retrieving pseudorange information from the GPS signal samples stored in the memory (12). The receiver (1) has a dormant mode of operation in which received GPS signals are sampled and stored in the memory (12) but the signal processor (13, 14) is not operative for retrieving pseudorange information, and an active mode of operation in which the signal processor (13, 14) is operative for retrieving pseudorange information.

Abstract: A method of obtaining a position fix in a GPS receiver is disclosed together with a GPS receiver for the same. The method comprising the steps of (i) providing an estimate of clock offset between the GPS receiver and the GPS satellites; (ii) measuring a set of pseudoranges from the GPS receiver to GPS satellites; and (iii) either (a) resolving the set of pseudoranges obtained in step (ii) to obtain a position fix, or (b) providing an estimate of the position of the GPS receiver, resolving the set of pseudoranges obtained in step (ii) to obtain a position fix correction, and obtaining a position fix using the estimate of the position of the GPS receiver and the position fix correction, wherein resolving the pseudoranges in step (iii)(a) or step (iii)(b) does not involve resolving the pseudoranges for either a new clock offset or clock offset correction.

Abstract: The present invention provides for a method of acquiring direct sequence spread spectrum signals and in particular, GPS signals, including the steps of obtaining an integration result by avoiding integration over bit edges, and includes the steps of splitting the received signal (A) into a plurality of signal chunks alternatively across a respective plurality of channels (B,C), each channel being arranged to carry a series of signal chunks, the division being controlled in a timed manner responsive to the signal bit period so that the signal chunks of one of the series signals do not include bit edges.

Abstract: A cellular radio system comprises a radio coverage area formed by a plurality of cells (C1,C2), each cell having at least one primary station (PS1,PS2) including a radio transceiver for communicating with a secondary station (SS1,SS2) when in its cell. The or each secondary station is able to roam within the radio coverage area. In order to facilitate call handover the secondary station informs the infrastructure (PS1, PS2, 10) of its velocity and the infrastructure uses knowledge of the velocity to make a decision regarding handing over a call-in-progress from one cell to another cell. The velocity information may be provided by a GPS receiver (18) carried by a vehicle in which the secondary station is located and the information is relayed to the secondary station by way of a short range radio system. The secondary station uses the cellular system to forward this information to the infrastructure.

Abstract: A method of despreading a GPS spread spectrum signal received at a mobile unit MSl with assistance from a base station BS1 includes (a) receiving and despreading GPS signals at the base station and deriving GPS signal information therefrom; (b) estimating the location of the mobile unit; (c) modifying the OPS signal information so as reflect the GPS signal characteristics as would be observed at the estimated location of the mobile unit; (d) transmitting the GPS signal information from the base station to the mobile unit; (e) generating replica signals containing PRN codes corresponding to those of the GPS signal using the modified GPS signal information; and (f) performing a correlation of the GPS signal and the replica signals in order to acquire the GPS signal.

Abstract: A method of providing an estimate of GPS time from non-GPS timing information present in communications signals transmitted from a base station (BS1) to a first mobile communications device (MS1) is provided comprising the steps of (i) in a second mobile communications device (MS2), receiving corresponding non-GPS timing signals present in communications signals transmitted by the base station; (ii) in a GPS receiver (23, 24) of the second mobile communications device (MS2), obtaining at least one pseudorange to a GPS satellite (GPS SV) and obtaining an first estimate of GPS time; (iii) deriving a relationship between the receipt of timing signals received in step (i) and the estimate of GPS time obtained in step (ii); and (iv) from the non-GPS timing information received by the first mobile communications device (MS1) and the relationship derived in step (iii), calculating a second estimate of GPS time.

Abstract: A method of despreading a plurality of GPS spread spectrum signals received by a GPS receiver (24) is disclosed together with a GPS receiver (24) and a mobile communications device (MS1) (especially a mobile cellular telephone) for the same. The method comprises the steps of acquiring a first GPS signal from the stored samples; obtaining frequency information relating to variations in the frequency of the first acquired signal as measured by the GPS receiver; and using the frequency information to acquire a second GPS signal. The frequency information may be used to acquire the second GPS signal in the course of a single dwell and may also, for a digital GPS receiver, relate to variations in the frequency of the first acquired signal present in stored samples.

Abstract: A method of despreading GPS spread spectrum signals containing pseudorandom noise (PRN) code sequences and received by a GPS receiver (24) is disclosed together with a GPS receiver (24) and a mobile communications device (MS1) (especially a mobile cellular telephone) for the same. The method comprises the steps of providing Doppler information relating to an estimate of the variation in Doppler shift as observed on the target signal by the GPS receiver and which is attributable to the motion of the GPS satellite; and correlating the target signal with a reference signal containing corresponding PRN code sequences, wherein, in the course of a single dwell, the correlation is modified as a function of the Doppler information.

Abstract: A mobile device (MS) is disclosed comprising a GPS receiver (14) and an audible alarm (13, 15) configured to sound, during operation of the GPS receiver, in response to either adverse performance of the GPS receiver or to an event which is adverse or likely to be adverse to the performance of the GPS receiver. The alarm may sound in response to the inability of the GPS receiver to either acquire or track a GPS signal, or obtain or maintain a position fix. Also, the alarm may sound in response to movement of the GPS receiver, including acceleration and higher order movement of the GPS receiver, in so far as that movement is adverse to the performance of the GPS receiver.

Abstract: A method of providing travel related information to a user of a mobile communications device (MS1) is disclosed together with a corresponding mobile communications device (MS1) and a travel information beacon (11) for the same. The method comprising the steps of determining whether the mobile communications device (MS1) is either travelling on a transport (10), has recently traveled on a transport (10), or is likely to travel on a transport (10) at some time in the near future; and depending on the outcome of that determination, displaying to a user on the mobile communications device (MS1) selected travel related information.

Abstract: The present invention provides for spread spectrum receiver (1) and related method arranged for the receipt and processing of a spread spectrum signal wherein a PRN code is generated locally as an intended replica of a received signal code and a correlation threshold test is conducted on the received signal to determine the state of suspected code acquisition. The baseband signal derived from the received signal is processed by the microprocessor (14) but the correlation threshold test is conducted remote from the microprocessor (14) and a received signal is then flagged for subsequent processing by the microprocessor (14) if the threshold value according to the correlation threshold test is exceeded.

Abstract: A method of generating a time shifted replica signal (SLS) from a reference signal (SPS) comprising a series of samples (A to K) describing bits of a data message in which the sampling rate is at least twice the data message bit rate is disclosed. The method comprising the steps of determining the phases of the reference signal samples with respect to virtual epochs (41) of the data message bits of the reference signal (SPS); and composing the time shifted replica signal (SLS) from the reference signal samples as a function of the phases of the reference signal samples.

Abstract: The invention provides for a method of providing travel-related information to a mobile communications device (12) comprising determining the opposition of the mobile communications device (12), deriving at least one signal at the mobile communications device (12) indicative of the position of the mobile communications device (12) and indicative of a travel-related request initiated at the mobile communications device (12), and including the steps of retrieving travel service information from a transport service provider and responding to the travel-related request by calculating location and time information of a travel service (14) serving to fulfil the request, and providing an output at the mobile communications device (12) of the calculated location and time information of the travel service (14).

Abstract: A method of determining the position of a mobile unit (MS1) having a GPS receiver (24) is disclosed. The method comprising the steps of measuring mobile unit pseudoranges at the mobile unit (MS1) using the GPS receiver (24); providing reference pseudoranges corresponding to a reference location situated remote from the mobile unit (BS1); and determining the position of the mobile unit (MS1) relative to the reference location (BS1) as a function of both the reference pseudoranges and the mobile unit pseudoranges.

Abstract: A method and apparatus (1A) for receiving a spread spectrum signal at a mobile communications terminal, including the step of processing the signal for the purposes of signal acquisition and signal tracking, monitoring movement of the mobile terminal and deriving a signal indicative of a characteristic of movement of the mobile terminal, and further including changing the mode of the processing of the incoming spectrum signal in response to the signal indicating the said characteristic of movement of the mobile terminal.

Abstract: A method of providing an estimate of the location of first and second devices MS1, MS2 comprising the steps of obtaining at least one range measurement from the first device MS1 to a known reference point BS1, GPS SVs; obtaining at least one range measurement from the second device MS2 to a known reference point BS1, GPS SVs, the second device MS2 being located near to the first device MS1; and calculating an estimate of the location of the devices MS1, MS2 using range measurements obtained in respect of both the first and second devices MS1, MS2.

Abstract: A method of despreading a GPS spread spectrum signal received at a mobile unit MS1 with assistance from a base station BS1 is disclosed comprising the steps of (a) receiving and despreading GPS signals at the base station and deriving GPS signal information therefrom; (b) estimating the location of the mobile unit; (c) modifying the GPS signal information so as reflect the GPS signal characteristics as would be observed at the estimated location of the mobile unit; (d) transmitting the GPS signal information from the base station to the mobile unit; (e) generating replica signals containing PRN codes corresponding to those of the GPS signal using the modified GPS signal information; and (f) performing a correlation of the GPS signal and the replica signals in order to acquire the GPS signal.