Abstract: An apparatus having a corresponding computer program comprises a receiver to receive one or more wireless signals; and a measurement circuit to obtain measurements of one or more characteristics of each of the wireless signals; wherein one or more of a plurality of possible locations of the apparatus are selected based on the measurements and a plurality of associations each associating one of the possible locations with expected values for the measurements for the one of the possible locations.

Abstract: The present invention provides a method, system, and apparatus for rapidly acquiring and correlating synchronization codes for a mobile receiver used for position determination purposes. The receiver uses a processing unit to perform the correlation functions. The processing unit first computes, for each segment interval of the received signal, the phase offset of that interval. Each interval is appropriately adjusted to account for the computed phase offset. The processing unit then accumulates the phase-adjusted segment intervals, and may down-convert the accumulated signal to a baseband format from an intermediate frequency. The processing unit then correlates the accumulated signal with a reference signal to produce a correlation peak, from which the time delay of a synchronization code within the interval can be calculated. Ultimately, the receiver's position can be determined based on the calculated time delay.

Abstract: The present invention provides a method, system, and apparatus for estimating a pilot frequency of a television broadcast signal at a receiver. In one aspect, the receiver constitutes a mobile device that uses the estimated pilot frequency to facilitate the determination of position location of the mobile device. The receiver includes a processor which estimates the pilot frequency by computing a baseband version of the pilot signal relative to a reference frequency, defining time-shifted segments for the pilot signal and its baseband version, computing phase correction terms using the pilot signal and its baseband version, phase correcting each received signal segment, and estimating the pilot frequency. In another aspect of the invention, a phase-locked-loop is used to track the phase of the incoming pilot signal. The loop filter and/or the phase of the numerically controlled oscillator is scaled to account for the non-integer nature of samples within the received segments.

Abstract: An apparatus having a corresponding method and computer program comprises a front end to receive an orthogonal frequency division modulation (OFDM) signal comprising a plurality of OFDM symbols each comprising N samples and a cyclic prefix comprising M of the N samples, wherein M<N; a buffer to store the cyclic prefix for one of the OFDM symbols; and a correlator to generate a correlation output based on the cyclic prefix and the one of the OFDM symbols.

Abstract: A method, apparatus, and computer-readable media for determining the position of a user terminal comprises receiving, at the user terminal, a digital audio broadcast signal; and determining a pseudo-range between the user terminal and a transmitter of the digital audio broadcast signal based on a known component of the digital audio broadcast signal; wherein the position of the user terminal is determined based on the pseudo-range between the user terminal and the transmitter of the digital audio broadcast signal and a location of the transmitter of the digital audio broadcast signal.