Abstract: Methods, non-transitory machine-readable mediums, and system to provide location services are described. In an embodiment, a method provides receiving at least two position fixes for a trajectory of an electronic device, where the at least two position fixes are obtained intermittently, matching the at least two position fixes to points on a path indicated in map data, and computing a distance for the trajectory using distance information using the map data.

Abstract: The present invention provides a GPS receiver having a unique frequency plan, thereby eliminating interference due to internally generated frequencies. In general, the GPS receiver has downconversion circuitry that uses a first synthesizer output signal with a center frequency of 272F to reduce the L1 (308F) or L2 (240F) GPS signal to an intermediate frequency signal. The intermediate frequency signal is then digitized by sampling circuitry wherein the sampling circuitry is driven by a second synthesizer output with a center frequency of 8.5F. The resultant digitized signal contains the GPS information carried in the received GPS signal and has a center frequency of 2F. By selecting 8.5F as the basic reference for all internally generated frequencies, where F is 5.115 MHz, all internally generated frequencies are interrelated by nature and no internal signals in the RF-to-baseband conversion can interfere with the received GPS signal within its information bandwidth.

Abstract: The present invention provides a GPS receiver comprising sampling circuitry adapted to perform IF-to-baseband conversion. In general, the GPS receiver includes downconversion circuitry that uses a first synthesizer output signal to reduce an amplified GPS input signal to an intermediate frequency signal, and sampling circuitry that receives the intermediate frequency signal and produces a baseband digital representation of the amplified GPS input signal. The sampling circuitry performs IF-to-baseband conversion by using a sampling rate equal to the frequency of a second synthesizer output signal, where the sampling rate is selected such that only an alias of the IF signal having the appropriate baseband frequency is digitized.

Abstract: The correlation circuitry of the present invention operates in communication with a controller and transform circuitry to concurrently search a range of frequencies by correlating a received signal from the global positioning system (GPS) with a generated frequency and a generated code at a plurality of time offsets. The output of the correlation circuitry is provided to the transform circuitry, such as fast Fourier transform (FFT) circuitry, that transforms the output of the correlation circuitry. The results from the transformation circuitry are used by a GPS receiver to determine a frequency of the received GPS signal and a time offset associated with a ranging code carried in the received GPS signal.

Abstract: The global positioning system (GPS) receiver of the present invention operates to search a range of frequencies by correlating a baseband signal corresponding to a received GPS signal with a generated frequency and a generated code at a plurality of time offsets. Address translation logic operates to group results of the correlation according to the plurality of time offsets by translating addresses received from a direct memory access (DMA) controller in order to improve the efficiency of performing a fast Fourier transform (FFT) on the results of the correlation. The transformed data produced by the FFT process are used by the GPS receiver to determine a frequency of the received GPS signal and a time offset associated with a ranging code carried in the received GPS signal.

Abstract: The global positioning system (GPS) receiver of the present invention operates to search a range of frequencies by correlating a baseband signal corresponding to a received GPS signal with a generated frequency and a generated code at a plurality of time offsets. Address translation logic operates to group results of the correlation according to the plurality of time offsets by translating addresses received from a direct memory access (DMA) controller in order to improve the efficiency of performing a fast Fourier transform (FFT) on the results of the correlation. The transformed data produced by the FFT process are used by the GPS receiver to determine a frequency of the received GPS signal and a time offset associated with a ranging code carried in the received GPS signal.

Abstract: The correlation circuitry of the present invention operates in communication with a controller and transform circuitry to concurrently search a range of frequencies by correlating a received signal from the global positioning system (GPS) with a generated frequency and a generated code at a plurality of time offsets. The output of the correlation circuitry is provided to the transform circuitry, such as fast Fourier transform (FFT) circuitry, that transforms the output of the correlation circuitry. The results from the transformation circuitry are used by a GPS receiver to determine a frequency of the received GPS signal and a time offset associated with a ranging code carried in the received GPS signal.

Abstract: The present invention relates to a single semiconductor die having an integrated low noise amplifier, a radio frequency (RF) subsystem, and sampling circuitry for use in a GPS receiver. The low noise amplifier has electrical performance suitable to receive a GPS signal from a unity gain antenna, thereby eliminating the need for external gain or an active antenna. After being amplified, the GPS signal is processed by a RF subsystem such that the signal is filtered and downconverted to a baseband signal, and the baseband signal is digitized by the sampling circuitry.

Abstract: The present invention provides a GPS receiver having a unique frequency plan, thereby eliminating interference due to internally generated frequencies. In general, the GPS receiver has downconversion circuitry that uses a first synthesizer output signal with a center frequency of 272F to reduce the L1 (308F) or L2 (240F) GPS signal to an intermediate frequency signal. The intermediate frequency signal is then digitized by sampling circuitry wherein the sampling circuitry is driven by a second synthesizer output with a center frequency of 8.5F. The resultant digitized signal contains the GPS information carried in the received GPS signal and has a center frequency of 2F. By selecting 8.5F as the basic reference for all internally generated frequencies, where F is 5.115 MHz, all internally generated frequencies are interrelated by nature and no internal signals in the RF-to-baseband conversion can interfere with the received GPS signal within its information bandwidth.

Abstract: The present invention provides a GPS receiver comprising sampling circuitry adapted to perform IF-to-baseband conversion. In general, the GPS receiver includes downconversion circuitry that uses a first synthesizer output signal to reduce an amplified GPS input signal to an intermediate frequency signal, and sampling circuitry that receives the intermediate frequency signal and produces a baseband digital representation of the amplified GPS input signal. The sampling circuitry performs IF-to-baseband conversion by using a sampling rate equal to the frequency of a second synthesizer output signal, where the sampling rate is selected such that only an alias of the IF signal having the appropriate baseband frequency is digitized.

Abstract: The present invention provides a GPS receiver using a unique combination of fixed gain and variable gain amplifiers and signal quantization to achieve an integrated receiver that provides for GPS signal extraction with accurate position determination in the presence of interference at a signal level of −60 dBm. In general, the GPS receiver has downconversion circuitry that uses a first synthesizer output signal to reduce an amplified GPS signal to an intermediate frequency signal. Noise automatic gain control circuitry and a gain control circuit control a first variable amplifier and a second variable amplifier, respectively, such that the receiver continues to operate linearly and GPS information carried in the amplified GPS signal is not compressed. Digitization circuitry provides a baseband digitized signal representation of the GPS signal and for interference adaptation to maximize the signal-to-noise ratio of the digitized samples.