Abstract: A method of determining a GPS position fix is disclosed together with a corresponding GPS receiver and server for the same. The method comprising the steps of: (i) providing standard GPS ephemeris corresponding to that transmitted by a GPS satellite; (ii) providing supplemental GPS ephemeris including at least one parameter describing the fluctuation over time of at least one satellite orbit parameter of standard GPS ephemeris; (iii) measuring psuedoranges to GPS satellites; and (iv) determining a GPS position fix from both the standard and supplemental GPS ephemeris provided in steps (i) and (ii) respectively and the psuedoranges measured in step (iii).

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: A method of determining a GPS position fix is disclosed together with a corresponding GPS receiver and server for the same. The method comprising the steps of: (i) providing standard GPS ephemeris corresponding to that transmitted by a GPS satellite; (ii) providing supplemental GPS ephemeris including at least one parameter describing the fluctuation over time of at least one satellite orbit parameter of standard GPS ephemeris; (iii) measuring psuedoranges to GPS satellites; and (iv) determining a GPS position fix from both the standard and supplemental GPS ephemeris provided in steps (i) and (ii) respectively and the psuedoranges measured in step (iii).

Abstract: A system includes first (1) and one or more second devices (2). A first signal (61) and a second signal (62) are transmitted from the first (1) to second (2) device and a third signal (63) is transmitted from the second to the first device. The times of these signals (61, 62, 63) being transmitted and received are measured and used to calculate timing information including a correction for different clock rates in first and second local clocks in the first and second devices.

Abstract: A time shifted replica signal (SLS) is generated from a reference signal (SPS) including a series of samples (A to K) describing bits of a data message, the sampling rate being at least twice the data message bit rate. The phases of the reference signal samples are determined with respect to virtual epochs (41) of the data message bits of the reference signal (SPS). The time shifted replica signal (SLS) is composed from the reference signal samples as a function of the phases of the reference signal samples. In another embodiment, the time shifted replica signal (SLS) is composed from the reference signal samples (A to K), the sampling rate of the replica signal (SLS) being the same as that of the reference signal (SPS), at least one reference signal sample (A to K) not being present in the time shifted replica signal (SLS).

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: 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 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.