Abstract: The present invention discloses a GPS system that can operate in different modes depending on the network facilities and bandwidth available, the GPS information that can be acquired, or user or system requirements. The modes comprise standalone mode, where a mobile communications device computes the position of the device, an autonomous mode, where the mobile communications device transmits the computed position to a server, application, or PSAP in a communications network, a network aided mode, where the network aides the mobile communications device in determining the position of the device, a network based mode, and other modes.

Abstract: A power management system for managing power in a wireless device having a SPS receiver, communication device and a power source, the power management is described. The power management system may include a real-time clock, an input/output device, a radio frequency front-end and a SPS engine in signal communication with the real-time clock, input/output device and radio frequency front-end, the SPS engine capable of powering down itself, the input/output device and radio frequency front-end in response to determining a mode of operation.

Abstract: Flexible mounting devices for navigational/entertainment displays, especially for in-vehicle use, are described herein. In an embodiment, the flexible mounting device comprises a flexible gooseneck, a magnetic base magnetically attached to a front end of the gooseneck for holding a display, and a windshield suction attached to a back end of the gooseneck for providing windshield support from the rear by suctioning to the windshield of a vehicle. In another embodiment, the flexible mounting device comprises a flexible neck, which may be firmly attached to the dashboard of a vehicle with a sticky gel pad. The mounting device also comprises a counter weight attached to a back end of the flexible neck. The display is fixed to a front end of the flexible neck such that the display protrudes beyond the dashboard. The counter weight at the back end of the flexible neck counter balances the weight of the display at the front end, and thereby helps to provide a stable support.

Abstract: Described herein are systems and methods that are capable of determining receiver position and system time under weak signal conditions. When the receiver is unable to accurately determine the satellite signal travel time, e.g., due to weak signal reception or some other condition, the receiver can still estimate the pseudo-range for the satellite based on an initial receiver position and system time. In this case, the system and methods described herein provide the necessary initial receiver position and system time with enough accuracy to estimate the pseudo-range, even under weak signal conditions. The receiver can then use the estimated pseudo-range to determine a more accurate receiver position.

Abstract: Provided herein are systems and methods that enable a navigation receiver to determine receiver position using a low ppm (Parts Per Million) Real Time Clock (RTC) under weak satellite signal reception conditions without the need for timing information from navigation satellites or aiding systems. Under weak signal conditions, the receiver is unable to demodulate navigation data bits but may be able to synchronize with the one ms PN sequences and 20 ms data bit edges of a received signal. In this case, the receiver is unable to determine the signal travel time from the navigation data bits resulting in one ms and/or 20 ms integer ambiguities in the travel time. Systems and methods are provided for resolving these one ms and/or 20 ms integer ambiguities and correct or reconstruct the pseudorange measurements accordingly. The reconstructed pseudorange measurements are used to accurately determine the receiver position.

Abstract: A Global Navigation Satellite System (GNSS) receiver and associated method capable of acquiring weak GNSS signals from a plurality of GNSS satellites produces a GNSS signal's code time, carrier frequency, and data bit transition parameters for subsequent signal tracking and position fixing. The GNSS receiver includes a baseband signal processor with special functionalities for acquiring weak signals. In a preferred embodiment, the time and frequency uncertainty space is reduced using available information and then special techniques are used to rapidly search the remaining uncertainty space. Successive reversal of short-length correlations within a data bit interval (a block) enables data bit transition detection and data bit sign correction prior to coherent integration.

Abstract: The techniques to detect and mitigate the false reacquisition in a global satellite navigation receiver are disclosed. The false reacquisition due to frequency side-lobes and code autocorrelation secondary lobes are considered for mitigation. A set of two threshold values is used to detect correct reacquisition and reject false reacquisition. While the reacquisition of the signal is straight forward when the correlation is clear with the power above the first threshold, it is not so clear when the power is between two thresholds. So a further search for the maximum power among the retained dwells results in correct reacquisition. The search range depends upon the signal blockage interval and receiver dynamics. The feedback from navigational solution may be used to determine the search range both in frequency and code phase. In the case of frequency side-lobes, which occur only at specified frequency components, these frequencies are tested for maximum power response.

Abstract: Provided herein are systems and methods for achieving long coherent integration in a navigational receiver to improve the sensitivity of the receiver and enable the receiver to acquire, reacquire and track signals under very weak signal conditions. In an embodiment, phase compensation is computed based on estimated Doppler frequency, rate of change of the Doppler frequency with time, and second order rate of change of the Doppler frequency. The Doppler frequency may be computed from an orbital model or ephemeris. This phase compensation is used to compensate samples of the input signal for changes in the phase due to the Doppler frequency. Frequency components of the phase-compensated samples are then computed using a frequency analysis such as a Fast Fourier Transform (FFT). The maximum frequency component is taken as an error frequency and used to compensate the samples of the input signal for residual frequency error.

Abstract: The invention provides a method and apparatus to optimally estimate and adaptively compensate the temperature-induced frequency drift of a crystal oscillator in a navigational signal receiver. A Read-Write memory encodes two tables, one for looking up frequency drift values versus temperature readings and another one for valid data confirmation on the first table. The initially empty look-up table is gradually populated with frequency drift values while the receiver computes the frequency drift along with its position. During initial start of the receiver or re-acquisition of satellite signals, the stored frequency drift value corresponding to the current temperature is used. If no valid frequency drift value is available, the frequency drift value is computed based on the existing frequency drift values in the table. This invention reduces the Time-To-First-Fix (TTFF) of the receiver and enables the receiver to self-calibrate, thus no additional factory calibration would be necessary.

Abstract: The present invention provides a new baseband integrated circuit (IC) architecture for direct sequence spread spectrum (DSSS) communication receivers. The baseband IC has a single set of baseband correlators serving all channels in succession. No complex parallel channel hardware is required. A single on-chip code Numerically Controlled Oscillator (NCO) drives a pseudorandom number (PN) sequence generator, generates all code sampling frequencies, and is capable of self-correct through feedback from an off-chip processor. A carrier NCO generates corrected local frequencies. These on-chip NCOs generate all the necessary clocks. This architecture advantageously reduces the total hardware necessary for the receiver and the baseband IC thus can be realized with a minimal number of gate count. The invention can accommodate any number of channels in a navigational system such as the Global Positioning System (GPS), GLONASS, WAAS, LAAS, etc.