Sirf Technology, Inc.

Enuvis, Inc.

Anant Sahai

Andrew Chou

Wallace Mann

John Tsitsiklis

Benjamin Van Roy

Jesse Stone

Stefano Casadei

Wungkum Fong

Nainesh Agarwal

Systems and methods are provided to facilitate transactions or limit operations. According to one embodiment, region information is determined in accordance with information received by a user device from a local location device. A region requirement is also determined, and it is arranged for the user device to operate in accordance with the region information and the region requirement.

Systems and methods for facilitating transactions in accordance with a region requirement

Techniques are provided for synthesizing a long coherent I and Q correlation integral at a particular frequency by synthetically combining a sequence of shorter correlation integrals at the same or different frequency. Techniques are also provided for acquiring a carrier-modulated signal with an unknown shift of the carrier frequency, and possibly some additional unknown signal parameters. These techniques involve synthesizing coherent correlation sums at a fine frequency resolution, using coherent correlation sums that are calculated at a coarse frequency resolution. This approach allows for coherent processing of the received signal over an arbitrarily long time interval, while avoiding the excessive computational requirements of traditional methods.

Synthesizing coherent correlation sums at one or multiple carrier frequencies using correlation sums calculated at a coarse set of frequencies

System and method for mitigating the effects of narrowband noise in a location-determining signal are provided, wherein the location-determining signal is associated with a periodic reference signal, the embodiments include identifying a set of noisy frequencies in the signal, determining a set of frequencies to be removed, and removing the set of frequencies from either the location-determining signal or the reference signal, thereby removing the effects of narrowband noise from the location-determining signal.

Narrowband noise mitigation in location-determining signal processing

Synthesizing coherent correlation sums at one or multiple carrier frequencies using correlation sums calculated at a course set of frequencies

System and method to determine the location of a receiver are provided. The received signal is decomposed into signal chunks that are then correlated with the reference signals of the transmitting sources. In some embodiments, the signal chunks may be shorter than the period of the reference signals. For each signal source, a grid of correlation values is constructed containing one column of correlation values for each signal chunk. Each column contains correlation values for several code-phases. Probes are executed in the grid to acquire the location-determining signals. In some embodiments, a probe includes calculating the fourier transform of a row in the grid, yielding correlation values associated with a refined set of frequency values. Potential acquisitions are verified by processing increasing portions of the received signal. Confirmed acquisition may be used to aid further acquisitions. Some embodiments eventually compress the received signal down to a one period duration by means of an ultra-stacking method. Additional verification, comprising multi-peak test and multi-path tests, may be performed on the correlation magnitude curve obtained from the ultra-stacked signal. Finally, refined code-phase values are extracted from these correlation magnitude curves.

System and method to estimate the location of a receiver

Techniques are provided for fine-tuning estimates of a delay value for a sampled signal. One aspect of the invention is to perform, for the sampled signal, coarse-grained calculations of the In Phase and Quadrature (I and Q) correlation integrals at a limited number of points, wherein the calculations are performed over a range of hypothesized delay values. A range of delay values of interest are then determined from the coarse-grained calculations of the I and Q correlation integrals. A subset of I and Q values based on the coarse granularity calculations of the I and Q correlation functions is used to perform a time-domain interpolation to obtain fine-grained values of the I and Q integrals in the range of the delay values of interest. Magnitude calculations are performed based on the fine-grained values of the I and Q integrals. Fine-tuned estimates of delay value are based on the magnitude calculations. Alternatively, fine-tuned estimates of delay value are based on the template-matching approach.

Extracting fine-tuned estimates from correlation functions evaluated at a limited number of values

Techniques are provided for aiding in acquiring a signal using the data bit information that is associated with each signal source. One aspect of the invention is to use the data bit information that is associated with each signal source when calculating the In Phase and Quadrature correlation integrals by using the sampled data associated with the received signal. By using the data bit information that is associated with each signal source, coherent correlation may be performed by breaking the signal into data blocks and performing calculations on a block-by-block basis. Coherent correlation is the calculation of In Phase and Quadrature correlation integrals for sampled data that is associated with the received signal.

Signal acquisition using data bit information

A server provides GPS aiding data to mobile GPS receivers are provided with an enclosed environment (e.g., within a large building) where the received GPS signal is likely to be weak or suffer multipath signal interference. The server receives GPS signals from one or more antennas within the enclosed environment and measures the multipath error in the vicinity of each antenna. Using the multipath error data for various satellite positions at various times, the server creates a delay model for the enclosed environment to generate GPS aiding data for the mobile GPS receivers. A generic delay model can be created that is applicable to similarly constructed buildings.

System, method, apparatus and means for constructing building tomography and timing information

To determine the clock doppler of a signal receiver, sampled data received from a receiver into are divided into data segments of incremental length. The clock doppler is estimated based on correlating each data segment with the expected signal from each satellite, from a set of satellites, that is overhead the receiver. For each data segment, the correlated result of each satellite is used to refine subsequent calculations of the clock doppler of the next overhead satellite. When the clock doppler calculations for a data segment have been performed using all overhead satellites from the set of satellites, then the results for that data segment are used to refine the calculations for the next data segment. If a current bounds for the clock doppler value is within a pre-determined clock doppler bound-width value and a current bounds for a delay value is within a pre-determined delay bound-width value, then a magnitude template is determined using magnitude calculations of the I and Q correlation integrals obtained at various clock doppler values and various delay values.

Determining the spatio-temporal and kinematic parameters of a signal receiver and its clock by information fusion

To determine the location of a signal receiver, sampled data received from a receiver is divided into data segments of increasing length. Current ranges for a delay value and for a modulation frequency value are calculated relative to each satellite signal source that is overhead the signal receiver. Using the data segments of increasing length, the current ranges, estimates for the delay value and for the modulation frequency value are then iteratively calculated and updated. For each signal source, I and Q correlation integrals and their magnitude values are calculated using the modulation frequency value estimate and each of a range of delay values centered around the delay value estimate. The resulting magnitude-curve is interpolated using the calculated magnitude values. The location of the receiver is calculated using the shape of the magnitude-curve to represent the I and Q correlation integrals for each signal source.

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Berkeley, CA, United States of America

Anant Sahai