Abstract: A signal receiver receives a time-domain signal that includes a plurality of pilot tones at a plurality of corresponding frequencies. The time-domain signal is transmitted from a transmit location. The signal receiver extracts from the received time-domain signal pilot phase values corresponding to the pilot tones. The signal receiver computes a signal propagation time of the received time-domain signal by fitting an interpolation function to residual pilot phase values, corresponding to the extracted pilot phase values, and determines a slope of the interpolation function. The signal receiver computes a range between the transmit location and the signal receiver by multiplying the computed signal propagation time with the speed of light.

Abstract: A moving signal receiver determines a plurality of signal receiver positions and corresponding ranges to the moving signal receiver from a first terrestrial transmitter by, while positioned at each of a plurality of distinct positions, determining a position of the moving signal receiver based on signals received from one or more respective sources distinct from the first terrestrial transmitter; and while determining the position of the moving signal receiver, concurrently obtaining a respective range to the moving signal receiver from the first terrestrial transmitter. The moving signal receiver computes a location of the first terrestrial transmitter based on the plurality of signal receiver positions and corresponding ranges.

Abstract: A signal receiver includes an antenna interface for receiving signals from an antenna, analog signal processing circuitry coupled to the antenna interface for processing the received signals to produce filtered signals, sampling circuitry to sample the filtered signals so as to produce digitized received signals, a digital compensator to receive the digitized received signals and compensate for non-uniform group delay and amplitude distortion introduced by the analog signal processing circuitry to produce compensated digitized received signals, and a digital processor to process the compensated digitized received signals so as to produce a result.

Abstract: A signal receiver includes an antenna interface for receiving signals from an antenna, analog signal processing circuitry coupled to the antenna interface for processing the received signals to produce filtered signals, sampling circuitry to sample the filtered signals so as to produce digitized received signals, a digital compensator to receive the digitized received signals and compensate for non-uniform group delay introduced by the analog signal processing circuitry to produce compensated digitized received signals, and a digital processor to process the compensated digitized received signals so as to produce a result.

Abstract: A signal receiver receives a time-domain signal that includes a plurality of pilot tones at a plurality of corresponding frequencies. The time-domain signal is transmitted from a transmit location. The signal receiver extracts from the received time-domain signal pilot phase values corresponding to the pilot tones. The signal receiver computes a signal propagation time of the received time-domain signal by fitting an interpolation function to residual pilot phase values, corresponding to the extracted pilot phase values, and determines a slope of the interpolation function. The signal receiver computes a range between the transmit location and the signal receiver by multiplying the computed signal propagation time with the speed of light.

Abstract: A signal receiver includes an antenna interface for receiving signals from an antenna, analog signal processing circuitry coupled to the antenna interface for processing the received signals to produce filtered signals, sampling circuitry to sample the filtered signals so as to produce digitized received signals, a digital compensator to receive the digitized received signals and compensate for non-uniform group delay and amplitude distortion introduced by the analog signal processing circuitry to produce compensated digitized received signals, and a digital processor to process the compensated digitized received signals so as to produce a result.

Abstract: A signal receiver includes an antenna interface for receiving signals from an antenna, analog signal processing circuitry coupled to the antenna interface for processing the received signals to produce filtered signals, sampling circuitry to sample the filtered signals so as to produce digitized received signals, a digital compensator to receive the digitized received signals and compensate for non-uniform group delay introduced by the analog signal processing circuitry to produce compensated digitized received signals, and a digital processor to process the compensated digitized received signals so as to produce a result.

Abstract: Method and apparatus for improving the speed and accuracy of processing signals from global positioning system (GPS) receivers by ensuring access to GPS carrier signals that have been modulated with an encrypted P-code sequence. In one disclosed embodiment of the invention, GPS L1 and L2 signals are correlated with a locally generated P-code signal, bandpass filtered to enhance signal-to-noise ratio performance, and then cross-correlated to obtain a signal with an L1-L2 frequency component that facilitates the resolution of carrier cycle ambiguity. In another embodiment, received GPS signals are immediately converted to digital form, then digitally correlated with in-phase and quadrature components of a locally generated P-code signal. Signals resulting from the correlation are then integrated over timing intervals corresponding to a previously determined encryption period to provide in-phase (I) and quadrature (Q) samples.

Abstract: A technique for smoothing pseudorange code measurements made in a global positioning system (GPS) receiver, with carrier phase measurements, over an extended time interval but without distortion that usually results from a divergence between code-derived pseudorange measurements and carrier-derived measurements. The basic principle of the invention is to remove ionospheric effects and Doppler effects from the pseudorange code measurements prior to filtering over an extended time interval. Removal of ionospheric effects may be effected by applying corrections received from a reference receiver, or may be accomplished using measured or modeled ionospheric data available to the receiver. The invention is applicable to differential GPS position finding using remote receivers having only a single-frequency capability, but is also applicable to stand-alone GPS receivers of any type.