Abstract: Methods to achieve data bit synchronization from weak navigational satellite signals are based on a maximum likelihood criterion. The bit synchronization technique may be implemented by calculating a normalized dot product of two consecutive one-millisecond correlation values. Similar normalized dot products are calculated at intervals separated by one bit duration, and these dot products are summed and compared with pre-computed thresholds to declare bit edge detection. In another implementation, the normalized dot product of adjacent correlation values is replaced by a coherent integration powers of adjacent correlation values.

Abstract: A method and a voltage-controlled oscillator provide an output signal with a frequency within one of a plurality of frequency bands, while reducing or eliminating temperature-induced band-switching or other drifts in operating frequency. The band-switching is reduced or eliminated by providing a circuit that adjusts a tuning sensitivity according to a calibration performed under test conditions. For example, such a voltage-controlled oscillator may include (a) a digitally controlled variable current source for providing a first control current to select one of the frequency bands for the voltage-controlled oscillator; (b) a variable transconductance circuit providing a second control current to compensate a variation in operating frequency; and (c) a control circuit for varying the frequency of the output signal in accordance with the first and second control signals.

Abstract: A map-matching feedback interface uses added information to bound a mapping solution and calibrate a navigation system, thus enabling the navigation system to navigate more accurately over a longer period of time. The system recognizes erroneous measurements and reduces or eliminates them from the mapping solution, thus preventing position inaccuracies. The system interfaces the navigation system with a mapping system that feeds back map-based data to the navigation system and combines the map-matching feedback data with other sensor data to produce an accurate navigation solution even in environments where GPS or dead reckoning input data is inaccurate.

Abstract: A method for navigation processing in a satellite positioning system receiver is disclosed. A method in accordance with the present invention comprises separating the three SATPS satellites into a first pair and a second pair, constructing a primary solution and an alternate solution, wherein the primary solution and the alternate solution satisfy the measurement constraints, computing a Doppler difference estimate for the primary solution and a Doppler difference estimate for the alternate solution, computing Doppler difference residuals for the first pair and the second pair of SATPS satellites, and comparing the Doppler difference residuals for said primary and alternate solutions to determine a valid solution. Typically, the computing of a Doppler difference residuals comprises differencing a measured Doppler difference from an estimated Doppler difference for the first pair and the second pair of SATPS satellites.

Abstract: In a system and method for simultaneously receiving or switching between dual frequency carrier signals in a GPS receiver, the GPS receiver is adapted to utilize different harmonics of a sub-harmonic frequency generator, which may include a lower frequency voltage controlled oscillator (VCO) to detect the L1 and L2 GPS carriers. A sub-harmonic mixer may be used to simultaneously down convert the L1 and L2 signals to a lower intermediate frequency (IF). A second mixer may be an image reject (IR) mixer used to separate the downconverted L1 and L2 signals. This mixer may be configured to simultaneously monitor the L1 and L2 signals, or to switch between the L1 and L2 signals. High frequency switching is not required of the radio frequency (RF) input or local oscillator signals, and simultaneous L1 and L2 reception is enabled without and 3 dB image noise degradation.

Abstract: A system is described that utilizes an imager in a wireless device (102) in a wireless network (100) and transmits a digital image to a service center (120) that assists in identifying the location of the wireless device (102) within a cell site (104).

Abstract: The present invention is a method and apparatus that produces an estimate of the local oscillator (LO) frequency error using an external reference signal. The error estimate can be used for LO calibration, correction and other purposes. The present invention does not require the external reference signal to be a precision reference signal, nor does the present invention require that the reference signal be continuously supplied. Further, the present invention can be implemented exclusively in software, and therefore does not add to the size or weight of any device that it is resident in. Thus, the present invention can be added to microcontrollers and various specialized programmable digital ICs that were not initially designed for this task.

Abstract: A GPS server capable of receiving information for use in determining ionospheric errors using mathematical formulas and sending ionospheric error correction information to GPS receivers that are in a location capable of receiving the ionospheric error correction information.

Abstract: Provided herein is multi-function platform comprising a plurality of devices and a large memory that is external to the devices and shared among the devices. In an embodiment, a Direct Memory Access (DMA) controller is provided for each device to efficiently transfer data between the device and the shared memory. More than one DMA may be provided for a device. For example, separate DMAs may be provided for different components of a device that perform different subfunctions enabling efficient transfer of data between the different components of the device and the shared memory. In another embodiment, each device comprises a local embedded memory and is provided with a DMA for transferring data between the local memory and the shared memory. Examples of devices that can be included in the platform include a GNSS receiver, a audio player, a video player, a wireless communication device, a routing device, or the like.

Abstract: A system and method capable of mitigating the migration from the current GPS system to the Galileo system and allow a single satellite system positioning receiver to process both GPS signals and Galileo signals.

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 discloses methods, apparatuses, and systems for eliminating auto- and cross-correlation in weak signal CDMA systems, such as GPS systems. The invention uses parallel data paths that allow standard correlation of signals in parallel with verification of the lock signal to determine whether the system has locked onto the proper signal within the scanned signal window. The invention can be made with multiple CPUs, a single CPU with dual input modes, on multiple IC chips, or as a single IC chip solution for small, low cost reception, downconversion, correlation, and verification systems.

Abstract: An Aided Location Communication System (“ALCS”) is described. The ALCS may include a geolocation server including a non-GPS position server, at least one server aiding database, server position-determination module, and a server fusion module. The ALCS may also include an Aided Location Communication Device (“ALCD”) including a communication section in signal communication with the geolocation server, and a position-determination section having a GPS Engine.

Abstract: Systems and methods for obtaining corrected time information in a GPS-enabled device connected to a mobile handset via a short-range wireless network, such as a Bluetooth™ Piconet™. The mobile handset includes a GPS time and a network clock synchronized with a network clock in a short-range wireless network interface in the GPS-enabled device. The GPS-enabled device may send requests for time information to the mobile handset. The mobile handset receives the request and latches the network clock time and the GPS time. The captured network clock time and GPS times are sent to the GPS-enabled device in response to the request. The GPS-enabled device subtracts the captured network clock time from its own network clock time and adds the difference to the captured GPS time to obtain a corrected GPS time.

Abstract: The present invention discloses a method and an apparatus for improving measurement fault detection in a sequential measurement processing estimator, and is particularly applied to Global Positioning Receivers.

Abstract: A system and method for providing aiding information to a satellite positioning system (“SPS”) receiver. A digital satellite radio system satellite receives aiding information communicated from a positioning system. The digital satellite radio system broadcasts the aiding information in the data signals it broadcasts to its subscribers. The subscribers receive the aiding information at satellite radio receivers and communicate the aiding information to the SPS receiver. The data signals may also be communicated to terrestrial repeaters for re-broadcast at a higher power. The terrestrial repeaters may input a transmitter identifier to permit the satellite radio receiver to determine a geographical location of the terrestrial repeater as its own.

Abstract: The present invention discloses methods, apparatuses, and systems for eliminating auto- and cross-correlation in weak signal CDMA systems, such as GPS systems. The invention uses parallel data paths that allow standard correlation of signals in parallel with verification of the lock signal to determine whether the system has locked onto the proper signal within the scanned signal window. The invention can be made with multiple CPUs, a single CPU with dual input modes, on multiple IC chips, or as a single IC chip solution for small, low cost reception, downconversion, correlation, and verification systems.

Abstract: In one embodiment, a system and method of dead reckoning navigation for a vehicle uses a set of accelerometers. Sensed accelerometers from the set are converted into a vehicle body frame of reference set of accelerations. The resulting converted accelerations are then used to determine a dead-reckoning longitudinal acceleration for the vehicle. By integrating the longitudinal acceleration along a heading for the vehicle, a dead-reckoning-determined location for the vehicle is provided.

Abstract: The present invention provides systems and methods for reducing the ‘cold start’ TTFF of navigation receivers. The systems and methods receive geographical information from a user, such as the nearest city, state or country, and use this geographical information to approximate the position of the receiver. The systems and methods then make use of the approximate position to reduce the ‘cold start’ TTFF. In an embodiment, the approximate position of the receiver is determined from a co-ordinate database in the receiver based on the geographical information provided by the user. In another embodiment, a user provides geographical information to the receiver through a displayed map with several stages of zooming capability.

Abstract: Implementation of an improved matched filter system for despreading a PN code from a spread spectrum signal utilizes a matched filter system that may be broadly conceptualized as a system that optimizes the number of multipliers and adders utilized by the system in despreading a PN code from a spread spectrum signal. This lowers the power consumption of the improved matched filter system and increases the speed at which the system despreads the PN code from the spread spectrum signal.