Abstract: Techniques are provided for power management of a global positioning system (GPS) receiver. A methodology implementing the techniques according to an embodiment includes calculating a pedestal ionospheric delay based on a phase difference between a first GPS signal at a first center frequency and a second GPS signal at a second center frequency. The method also includes powering off a processing chain configured to provide the second GPS signal. The method further includes calculating, at periodic intervals, a secondary ionospheric delay based on a phase difference between an upper sideband and a lower sideband of the first GPS signal and accumulating differences between consecutively calculated secondary ionospheric delays. The method further includes, in response to the accumulated differences exceeding a threshold value, powering on the processing chain configured to provide the second GPS signal and recalculating the pedestal ionospheric delay.

Abstract: A signal acquisition device includes a first stage processing module and a second stage processing module. The first stage processing module is configured to correlate a first set of a plurality of radio frequency (RF) signal samples to a plurality of generated tones, and to output a plurality of interpolated (candidate) tones each having first correlation magnitudes exceeding a first threshold value. The second stage processing module is configured to correlate a second set of the RF signal samples to a plurality of code signals, and to output a plurality of output tones each having second correlation magnitudes exceeding a second threshold value, where the second set of RF signal samples correspond to the interpolated tones.

Abstract: Techniques are provided for power management of a global positioning system (GPS) receiver. A methodology implementing the techniques according to an embodiment includes calculating a pedestal ionospheric delay based on a phase difference between a first GPS signal at a first center frequency and a second GPS signal at a second center frequency. The method also includes powering off a processing chain configured to provide the second GPS signal. The method further includes calculating, at periodic intervals, a secondary ionospheric delay based on a phase difference between an upper sideband and a lower sideband of the first GPS signal and accumulating differences between consecutively calculated secondary ionospheric delays. The method further includes, in response to the accumulated differences exceeding a threshold value, powering on the processing chain configured to provide the second GPS signal and recalculating the pedestal ionospheric delay.

Abstract: Techniques are provided for employing an embedded software defined radio (SDR) in a navigation system. A navigation system implementing the techniques according to an embodiment includes a global positioning system (GPS) receiver configured to acquire and track received GPS signals. The system also includes an SDR configured to process received communication signals. The communication signals include timing data. The SDR is further configured to calculate position and navigation data based on a combination of the processed communication signals and the tracked GPS signals provided by the GPS receiver. The system further includes a system timer configured to provide a common time base for use by the GPS receiver and the SDR. The navigation system is implemented in an application specific integrated circuit (ASIC).

Abstract: A signal acquisition and tracking device includes an input configured to receive a global navigation satellite system (GNSS) signal, a software-based processor configured to execute software instructions to acquire the GNSS signal via the input and to generate, based on the acquired signal, one or more signal tracking parameters, and a hardware logic circuit operatively coupled to the processor. The logic circuit is configured to track the GNSS signal independently of the processor using the one or more signal tracking parameters generated by the processor. In some examples, the processor is configured to pull in and center the GNSS signal in time and frequency, and the logic circuit is further configured to track the pulled in and centered GNSS signal independently of the processor. In some examples, the processor acquires the signal and then hands-off control to the logic circuit for subsequent tracking of the signal.

Abstract: Techniques are provided for batch processing signal acquisition. A batch processing signal acquisition system implementing the techniques according to an embodiment includes a recording controller configured to store samples of an input signal to a memory. The input signal is received at a first sampling rate. The system also includes a playback controller configured to read samples from the memory for playback of the input signal at a second sampling rate. The system further includes an acquisition processor configured to detect and locate, in time and frequency, a signal of interest in the playback of the input signal. The system further includes a signal processor configured to process the signal of interest in the playback of the input signal based on the detection and location provided by the acquisition processor.

Abstract: Techniques are provided for batch processing signal acquisition. A batch processing signal acquisition system implementing the techniques according to an embodiment includes a recording controller configured to store samples of an input signal to a memory. The input signal is received at a first sampling rate. The system also includes a playback controller configured to read samples from the memory for playback of the input signal at a second sampling rate. The system further includes an acquisition processor configured to detect and locate, in time and frequency, a signal of interest in the playback of the input signal. The system further includes a signal processor configured to process the signal of interest in the playback of the input signal based on the detection and location provided by the acquisition processor.

Abstract: Techniques are provided for employing an embedded software defined radio (SDR) in a navigation system. A navigation system implementing the techniques according to an embodiment includes a global positioning system (GPS) receiver configured to acquire and track received GPS signals. The system also includes an SDR configured to process received communication signals. The communication signals include timing data. The SDR is further configured to calculate position and navigation data based on a combination of the processed communication signals and the tracked GPS signals provided by the GPS receiver. The system further includes a system timer configured to provide a common time base for use by the GPS receiver and the SDR. The navigation system is implemented in an application specific integrated circuit (ASIC).

Abstract: A digital radio includes an input configured to receive an input signal and an analog-to-digital converter (ADC) configured to sample analog data in the input signal into a digital input signal. The digital input signal has first digital data encoded at a first data rate modulated at a first frequency. The digital radio further includes a signal processor configured to generate, based on the digital input signal, a digital output signal having second digital data encoded at a second data rate modulated at a second frequency. The first data rate is different from the second data rate and/or the first frequency is different from the second frequency. The digital radio further includes an output configured to provide the digital output signal to a target device, where the second data rate and the second frequency match a frequency plan of the target device.

Abstract: A global navigation satellite system (GNSS) receiver can include a code generator, a signal correlator circuit, and a processor. The code generator can generate samples of a plurality of ranging codes associated with corresponding GNSS transmitters. The signal correlator circuit can receive, according to a first clock rate, samples of a signal from a GNSS transmitter, and update, according to a second clock rate and a time division multiplexing scheme, cross-correlation values indicative of cross-correlations between the signal and a subset of the plurality of ranging codes. The second clock rate can be equal to at least multiple times the first clock rate. The signal correlator circuit can determine final results of the cross-correlation values based on the updating of the cross-correlation values, and a processor can identify the GNSS transmitter among the plurality of GNSS transmitters based on the final results of the cross correlation values.

Abstract: A global navigation satellite system (GNSS) receiver is disclosed. In embodiments, the GNSS receiver includes a tracking engine running on a primary controller, the tracking engine configured to receive a plurality of signals from a plurality of satellites. The GNSS receiver further includes a space-time adaptive correlator (STAC) engine running on an application-specific controller. In embodiments, the STAC engine is configured to: receive initial position data and an initial receiver clock estimate from the tracking engine; construct a spatial hypercube based on the received initial position data; receive the plurality of signals from the tracking engine; interpolate signal strengths of the plurality of signals to generate a plurality of signal intensity curves; integrate the plurality of signal intensity curves within the spatial hypercube for the initial receiver clock estimate to generate a signal intensity hypercube plot; and determine a receiver position based on the signal intensity hypercube plot.

Abstract: A global navigation satellite system (GNSS) receiver can include a code generator, a signal correlator circuit, and a processor. The code generator can generate samples of a plurality of ranging codes associated with corresponding GNSS transmitters. The signal correlator circuit can receive, according to a first clock rate, samples of a signal from a GNSS transmitter, and update, according to a second clock rate and a time division multiplexing scheme, cross-correlation values indicative of cross-correlations between the signal and a subset of the plurality of ranging codes. The second clock rate can be equal to at least multiple times the first clock rate. The signal correlator circuit can determine final results of the cross-correlation values based on the updating of the cross-correlation values, and a processor can identify the GNSS transmitter among the plurality of GNSS transmitters based on the final results of the cross correlation values.

Abstract: A global navigation satellite system (GNSS) receiver is disclosed. In embodiments, the GNSS receiver includes a tracking engine running on a primary controller, the tracking engine configured to receive a plurality of signals from a plurality of satellites. The GNSS receiver further includes a space-time adaptive correlator (STAC) engine running on an application-specific controller. In embodiments, the STAC engine is configured to: receive initial position data and an initial receiver clock estimate from the tracking engine; construct a spatial hypercube based on the received initial position data; receive the plurality of signals from the tracking engine; interpolate signal strengths of the plurality of signals to generate a plurality of signal intensity curves; integrate the plurality of signal intensity curves within the spatial hypercube for the initial receiver clock estimate to generate a signal intensity hypercube plot; and determine a receiver position based on the signal intensity hypercube plot.

Abstract: A global navigation satellite system (GNSS) receiver can include a code generator, a signal correlator circuit, and a processor. The code generator can generate samples of a plurality of ranging codes associated with corresponding GNSS transmitters. The signal correlator circuit can receive, according to a first clock rate, samples of a signal from a GNSS transmitter, and update, according to a second clock rate and a time division multiplexing scheme, cross-correlation values indicative of cross-correlations between the signal and a subset of the plurality of ranging codes. The second clock rate can be equal to at least multiple times the first clock rate. The signal correlator circuit can determine final results of the cross-correlation values based on the updating of the cross-correlation values, and a processor can identify the GNSS transmitter among the plurality of GNSS transmitters based on the final results of the cross correlation values.

Abstract: A computer-implemented method and device for determining a user position, implemented in a user handheld computing device programmed to perform the method. The method includes solving for the position of a user based on ranges, which are computed by estimating power loss between a user and a number of Wi-Fi Access Points. Embodiments of the present invention includes a method that is designed to accommodate the non-linear nature of solving a position solution using power estimates. This method includes solving a two-dimensional solution grid of position residuals, or magnitudes of error between true and computed ranges, using signal strength measurements from multiple Wi-Fi access points in order to determine local minima of the position residuals indicating a user position. Standard approaches in the area such as a Least Squares Solution overly simplify the non-linear components resulting in poor performance.

Abstract: A computer-implemented method and device for determining a user position, implemented in a user handheld computing device programmed to perform the method. The method includes solving for the position of a user based on ranges, which are computed by estimating power loss between a user and a number of Wi-Fi Access Points. Embodiments of the present invention includes a method that is designed to accommodate the non-linear nature of solving a position solution using power estimates. This method includes solving a two-dimensional solution grid of position residuals, or magnitudes of error between true and computed ranges, using signal strength measurements from multiple Wi-Fi access points in order to determine local minima of the position residuals indicating a user position. Standard approaches in the area such as a Least Squares Solution overly simplify the non-linear components resulting in poor performance.