Abstract: An adjustable code generator is configurable to generate any of a plurality of spread-spectrum code signals. The adjustable code generator includes a feedback polynomial mask table to contain a set of feedback polynomial masks. Respective feedback polynomial masks of the set correspond to respective spread-spectrum code signals of the plurality of spread-spectrum code signals. The adjustable code generator also includes control logic to select any of the feedback polynomial masks of the set contained in the feedback polynomial mask table, and further includes a shift register to provide, at an output, a respective spread-spectrum code signal that corresponds to a feedback polynomial mask selected by the control logic and to receive feedback generated using the feedback polynomial mask selected by the control logic.

Abstract: An adjustable code generator is configurable to generate any of a plurality of spread-spectrum code signals. The adjustable code generator includes a feedback polynomial mask table to contain a set of feedback polynomial masks. Respective feedback polynomial masks of the set correspond to respective spread-spectrum code signals of the plurality of spread-spectrum code signals. The adjustable code generator also includes control logic to select any of the feedback polynomial masks of the set contained in the feedback polynomial mask table, and further includes a shift register to provide, at an output, a respective spread-spectrum code signal that corresponds to a feedback polynomial mask selected by the control logic and to receive feedback generated using the feedback polynomial mask selected by the control logic.

Abstract: A satellite navigation device including a flexible radio frequency (RF) receiver is described. The receiver receives a signal that includes at least a first spread-spectrum signal from a first satellite. The receiver has a first channel that includes an analog-to-digital (A/D) converter to sample and quantize the signal and an automatic gain control (AGC) to adjust an amplification of the signal. The A/D converter has a first non-zero quantization threshold magnitude and a second non-zero quantization threshold magnitude. The AGC may adjust a gain in accordance with the first non-zero quantization threshold magnitude. The gain may correspond to a first pre-determined probability of a non-zero sample and the second non-zero quantization threshold magnitude may correspond to a second pre-determined probability of a non-zero sample.

Abstract: A satellite navigation device including a receiver having an adjustable code generator is described. The adjustable code generator is configurable to generate a set of spread-spectrum code signals. Each spread-spectrum code signal has a respective length corresponding to a repetition period. The set of spread-spectrum code signals includes first and second spread-spectrum code signals having distinct first and second lengths.

Abstract: A system and a method to track GPS (Global Positioning System) satellite signal in a GPS receiver that includes an expanded capture window to rapidly reacquire the satellite signal after the satellite signal has been obstructed or when there is other type of signal loss. The expanded capture window includes a plurality of additional early and late correlations for maintaining synchronization of the GPS signal with a generated replica signal when positional error has accumulated during the time of the signal loss. The plurality of additional early and late correlations may be delayed from each other by a multiple of a fraction of a chip and may be performed in one or multiple channels of the GPS receiver. The adjoining code samples in the replica signal may also be offset by a fraction of a chip or by a multiple of the fraction of a chip.

Abstract: The present invention uses at least one amplitude bit to assist the phase-sampling technique used in digital receiver architectures. For digital receivers where the Intermediate Frequency (IF) is an integer multiple of the fundamental frequency f0, the present invention provides reduced processing complexity and reduced power consumption. The present invention allows the digital receiver to avoid performing coordinate rotation at high speeds, and replaces such a coordinate rotation with a simple phase subtraction. This replacement of the coordinate rotation allows the receiver to use a less complicated design, and to consume less power as a result.

Abstract: A GPS receiver system determines the presence of trackable signals at code delays less than the prompt delay being tracked for a particular signal and changes the prompt delay to correspond to the smallest code delay having a trackable signal. Trackable signals at large code delays are multipath signals and may be separately tracked to aid in dead reckoning. The trackable signals at code delays not adjacent to the current tracked prompt delay may be tracked in the same channel as the prompt delay so that all satellite channels are continuously evaluated for multipath signals being tracked or a non-satellite specific channel may be used to sequentially step through the satellite signals to evaluate multipath on a satellite by satellite basis.

Abstract: A terrestrial C/A code GPS receiver system digitally samples, filters and stores a segment of 11 half chips of the received composite as a binary number and multiplexes this number for parallel correlation with each of a series of multibit code replicas for the satellites to be tracked. Each of the time delay specific correlation products are accumulated in a cell of a memory matrix so that at least twenty two delays for each satellite may be evaluated each code period providing fast reacquisition, even within a city intersection, as well as correction of multipath tracking and multipath interference. All cells of the memory matrix may be used for an acquisition of a single satellite in about 4 ms. Two satellite tracking, in addition to altitude hold, uses cross track hold alternating with clock hold to update the cross track estimate. Single satellite tracking uses cross track and clock hold together. Navigation data is updated with detected changes in motion including turns.

Abstract: A GPS receiver system determines the presence of trackable signals at code delays less than the prompt delay being tracked for a particular, signal and changes the prompt delay to correspond to the smallest code delay having a trackable signal. Trackable signals at large code delays are multipath signals and may be separately tracked to aid in dead reckoning. The trackable signals at code delays not adjacent to the current tracked prompt delay may be tracked in the same channel as the prompt delay so that all satellite channels are continuously evaluated for multipath signals being tracked or a non-satellite specific channel may be used to sequentially step through the satellite signals to evaluate multipath on a satellite by satellite basis.

Abstract: A CDMA coded, spread spectrum radio signal containing a strong signal and a weak signal is received, and the interference of the strong signal with the weak signal is computed to enhance the ability to track the weak signal. The codes modulating both signals are known, and the weak signal can be predicted. The interference of the strong signal is calculated as the product of the amplitude of the strong signal and the predicted crosscorrelation of the strong signal with the weak signal. The strong signal may be measured, predicted, or acquired through a combination of both methods. The crosscorrelation may be predicted for a range of weak signal values, and the weak signal selected as the prediction producing the greatest received power.

Abstract: The present invention uses at least one amplitude bit to assist the phase-sampling technique used in digital receiver architectures. For digital receivers where the Intermediate Frequency (IF) is an integer multiple of the fundamental frequency fo, the present invention provides reduced processing complexity and reduced power consumption. The present invention allows the digital receiver to avoid performing coordinate rotation at high speeds, and replaces such a coordinate rotation with a simple phase subtraction. This replacement of the coordinate rotation allows the receiver to use a less complicated design, and to consume less power as a result.

Abstract: A spread spectrum receiver uses a comparison of the magnitude of the code correlation amplitudes at equal power at a one chip spacing to the magnitude at a central position there between to determine if multipath interference is present. The lead or lag error from constructive or destructive multipath interference may also be determined. Inaccuracies due to such interference may then be corrected or minimized by, for example, determining the residual code phase error and/or the prompt or accurate code phase delay.

Abstract: A terrestrial C/A code GPS receiver system digitally samples, filters and stores a segment of 11 half chips of the received composite as a binary number and multiplexes this number for parallel correlation with each of a series of multibit code replicas for the satellites to be tracked. Each of the time delay specific correlation products are accumulated in a cell of a memory matrix so that at least twenty two delays for each satellite may be evaluated each code period providing fast reacquisition, even within a city intersection, as well as correction of multipath tracking and multipath interference. All cells of the memory matrix may be used for an acquisition of a single satellite in about 4 ms. Two satellite tracking, in addition to altitude hold, uses cross track hold alternating with clock hold to update the cross track estimate. Single satellite tracking uses cross track and clock hold together. Navigation data is updated with detected changes in motion including turns.

Abstract: A GPS receiver system determines the presence of trackable signals at code delays less than the prompt delay being tracked for a particular, signal and changes the prompt delay to correspond to the smallest code delay having a trackable signal. Trackable signals at large code delays are multipath signals and may be separately tracked to aid in dead reckoning. The trackable signals at code delays not adjacent to the current tracked prompt delay may be tracked in the same channel as the prompt delay so that all satellite channels are continuously evaluated for multipath signals being tracked or a non-satellite specific channel may be used to sequentially step through the satellite signals to evaluate multipath on a satellite by satellite basis.

Abstract: A terrestrial C/A code GPS receiver system digitally samples, filters and stores a segment of 11 half chips of the received composite as a binary number and multiplexes this number for parallel correlation with each of a series of multibit code replicas for the satellites to be tracked. Each of the time delay specific correlation products are accumulated in a cell of a memory matrix so that at least twenty two delays for each satellite may be evaluated each code period providing fast reacquisition, even within a city intersection, as well as correction of multipath tracking and multipath interference. All cells of the memory matrix may be used for an acquisition of a single satellite in about 4 ms. Two satellite tracking, in addition to altitude hold, uses cross track hold alternating with clock hold to update the cross track estimate. Single satellite tracking uses cross track and clock hold together. Navigation data is updated with detected changes in motion including turns.

Abstract: A GPS receiver system determines the presence of trackable signals at code delays less than the prompt delay being tracked for a particular signal and changes the prompt delay to correspond to the smallest code delay having a trackable signal. Trackable signals at large code delays are multipath signals and may be separately tracked to aid in dead reckoning. The trackable signals at code delays not adjacent to the current tracked prompt delay may be tracked in the same channel as the prompt delay so that all satellite channels are continuously evaluated for multipath signals being tracked or a non-satellite specific channel may be used to sequentially step through the satellite signals to evaluate multipath on a satellite by satellite basis.

Abstract: A terrestrial C/A code GPS receiver system digitally samples, filters and stores a segment of 11 half chips of the received composite as a binary number and multiplexes this number for parallel correlation with each of a series of multibit code replicas for the satellites to be tracked. Each of the time delay specific correlation products are accumulated in a cell of a memory matrix so that at least twenty two delays for each satellite may be evaluated each code period providing fast reacquisition, even within a city intersection, as well as correction of multipath tracking and multipath interference. All cells of the memory matrix may be used for an acquisition of a single satellite in about 4 ms. Two satellite tracking, in addition to altitude hold, uses cross track hold alternating with clock hold to update the cross track estimate. Single satellite tracking uses cross track and clock hold together. Navigation data is updated with detected changes in motion including turns.

Abstract: A CDMA coded, spread spectrum radio signal containing a strong signal and a weak signal is received, and the interference of the strong signal with the weak signal is computed to enhance the ability to track the weak signal. The codes modulating both signals are known, and the weak signal can be predicted. The interference of the strong signal is calculated as the product of the amplitude of the strong signal and the predicted crosscorrelation of the strong signal with the weak signal. The strong signal may be measured, predicted, or acquired through a combination of both methods. The crosscorrelation may be predicted for a range of weak signal values, and the weak signal selected as the prediction producing the greatest received power.

Abstract: A terrestrial C/A code GPS receiver system digitally samples, filters and stores a segment of 11 half chips of the received composite as a binary number and multiplexes this number for parallel correlation with each of a series of multibit code replicas for the satellites to be tracked. Each of the time delay specific correlation products are accumulated in a cell of a memory matrix so that at least twenty two delays for each satellite may be evaluated each code period providing fast reacquisition, even within a city intersection, as well as correction of multipath tracking and multipath interference. All cells of the memory matrix may be used for a acquisition of a single satellite in about 4 ms. Two satellite tracking, in addition to altitude hold, uses cross track hold alternating with clock hold to update the cross track estimate. Single satellite tracking uses cross track and clock hold together. Navigation data is updated with detected changes in motion including turns.

Abstract: A GPS receiver system determines the presence of trackable signals at code delays less than the prompt delay being tracked for a particular signal and changes the prompt delay to correspond to the smallest code delay having a trackable signal. Trackable signals at large code delays are multipath signals and may be separately tracked to aid in dead reckoning. The trackable signals at code delays not adjacent to the current tracked prompt delay may be tracked in the same channel as the prompt delay so that all satellite channels are continuously evaluated for multipath signals being tracked or a non-satellite specific channel may be used to sequentially step through the satellite signals to evaluate multipath on a satellite by satellite basis.