Abstract: Methods and systems consistent with the present invention provide a method for dynamically controlling power consumption in a digital demodulator circuit by varying clock rates and bit widths of demodulator components including an analog to digital converter, decimation filter, OFDM operating engine, FEC decoder, and MPE-FEC processor, according to parameters and conditions of the received signal including modulation mode, signal to noise ratio, effective bit transmission rate, bit error rate, packet error rate, adjacent channel interference, and co-channel interference.

Abstract: A method for GPS navigation which uses an interacting multiple-model (IMM) estimator with a probabilistic data association filter (PDAF) improves navigation performance. The method includes (a) providing two or more models of GPS navigation, with each model characterized by a model state vector which is updated periodically, (b) providing for each model a corresponding filter for deriving, for each period, a current value for the corresponding model state vector based on current measurements made on parameters affecting the corresponding state vector; and (c) applying an interacting multiple model (IMM) estimator to provide, for each period, a current value for a system state vector using the current values of the model state vectors for that period and their corresponding filters. Each model state vector may include one or more of the following: variables: 3-dimensional position, 3-dimensional velocity, satellite clock bias, satellite clock drifts and one or more other satellite parameters.

Abstract: Methods and systems consistent with the present invention provide a host based positioning system. The host based positioning system includes a tracker hardware interface that connects to a dedicated hardware space vehicle tracker to a host computer. The tracker hardware interface receives positioning information from the space vehicle tracker and communicates with the host computer using predefined messages. The host based positioning system includes a layered protocol approach to enable user applications on a host computer to access data from tracker hardware device.

Abstract: A signal processing system control method and apparatus are described. Various embodiments include a signal processing system with multiple subsystems. A method for controlling the signal processing system includes storing channel records in a designated area of shared memory. Channel records include channel data that include one of multiple discrete signals to be processed by multiple subsystems in a time-multiplexed manner. The channel record includes information used by the multiple subsystems to process a channel, including information used to configure the multiple subsystems, information used to allocate the shared memory, and information used to communicate between multiple subsystems.

Abstract: The present invention discloses analog methods and circuits for compression of the GPS C/A signal to audio bandwidths to improve TTFF times, as well as decreasing auto correlation errors in systems that employ the methods and devices disclosed.

Abstract: A method and apparatus for a spread spectrum matched filter with Doppler correction suitable for using in a radio frequency receiver. The system includes a signal sampler operable to receive signal data and a Doppler shift system operable to provide a Doppler shift correction value. The system also includes a time domain signal processor in signal communication with the signal sampler, the Doppler shift system and the code signal input, the time domain signal processor operable to shift the signal data by the Doppler shift correction value and to determine a correlation between the shifted signal data and the code signal input. The system reduces a waveform representing Doppler correction values into a Boolean combination that may selectively represent the waveform and be implemented by the processing of a matched filter.

Abstract: Generic SATPS receivers and methods for configuring generic SATPS receivers that include a plurality of outputs are provided. These configurable SATPS receivers are adapted to be utilized in at least one of a plurality of particular SATPS receiver applications, and can also include a plurality of input paths, and a means for generating selected ones of the plurality of possible outputs. Selected ones of the plurality of outputs are enabled/disabled based on at least one requirement of the particular receiver application to configure or program the generic SATPS receiver to function as a SATPS receiver used for a particular SATPS receiver application or operating environment. The selected ones of the plurality of outputs can be defined by and can be those utilized by the particular SATPS receiver application or operating environment.

Abstract: The present invention provides systems and methods that enable a standalone receiver capable of downloading navigation data under weak signal conditions. In an embodiment, a standalone navigation receiver generates predicted satellite orbits based on the tracking history of the satellites stored in the receiver. The tracking history comprises historical navigation data previously received from the satellites. The receiver uses the predicted satellite orbit to generate navigation data such as ephemeris and almanac. Since the predicted satellite is accurate, the generated navigation data is similar to the navigation data transmitted by the navigation satellites, and can therefore be used by the receiver to correct the downloaded navigation data bits. Thus many of the bits of a downloaded navigation word, especially the higher order significant bits of the word can be corrected. The remaining bit errors can be resolved based on a parity check of the word.

Abstract: A GPS Mobile Unit is described. The GPS Mobile Unit may include at least two antennas, at least two GPS receivers, and a position solution module in signal communication with the at least two GPS receivers.

Abstract: Systems and methods for detecting global positioning system (GPS) measurement errors are provided. In this regard, a representative system, among others, includes a navigation device that is configured to receive GPS signals from signal sources, the navigation device being configured to calculate pseudoranges (PRs) and delta ranges (DRs) based on the received GPS signals, the navigation device including a consistency check algorithm that is configured to: determine mismatches between the respective calculated PRs and DRs, and indicate that an error exists in the respective calculated PRs and DRs based on their mismatch and mismatch accumulations. This algorithm can be independent of navigation state and is capable of detecting slow-changing errors.

Abstract: Systems and methods for processing navigational solutions are provided. In this regard, a representative system includes a navigational computing device comprising a processor and memory that stores a navigational solution manager that is executed by the processor to provide a receiver position. The navigational solution manager is configured to collect navigational data from at least one satellite vehicle, compute initialization navigational measurements based on the collected navigational data, and compute the receiver position using the initialization navigation measurements.

Abstract: Systems and methods for global differential positioning are provided. In this regard, a representative system, among others, may include a first receiver being configured to receive global correction data from a single source; and a computing device being configured to adjust positional estimates based on the received global correction data. A representative method, among others, for global differential positioning may include receiving satellite measurement information; receiving global correction data from a single source; generating location information based on the received satellite information; adjusting the location information based on the global correction data to produce adjusted location information; and delivering the adjusted location information.

Abstract: Systems and methods for sharing an oscillator between receivers are disclosed. A representative method (among others) of responding to a change in frequency of a voltage-controlled temperature-compensated oscillator (VCTCXO), includes: determining a new value for VCTCXO frequency; determining a time at which the new value will be applied to the VCTCXO; transmitting the time and the new value to a subsystem that uses a second receiver which shares the VCTCXO with a first receiver; and in the subsystem, updating channel context data to use the time of the change in frequency and the new value.

Abstract: A GPS RF Front End IC containing a Programmable Frequency Synthesizer is disclosed. The GPS RF front end IC having a programmable frequency synthesizer allows a relatively fixed internal frequency plan while able to use a number of different reference frequencies provided by the host platform, which can be a wireless phone, or other such device, which can provide an accurate reference frequency signal.

Abstract: Generic SATPS receivers and methods for configuring generic SATPS receivers that include a plurality of outputs are provided. These configurable SATPS receivers are adapted to be utilized in at least one of a plurality of particular SATPS receiver applications, and can also include a plurality of input paths, and a means for generating selected ones of the plurality of possible outputs. Selected ones of the plurality of outputs are enabled/disabled based on at least one requirement of the particular receiver application to configure or program the generic SATPS receiver to function as a SATPS receiver used for a particular SATPS receiver application or operating environment. The selected ones of the plurality of outputs can be defined by and can be those utilized by the particular SATPS receiver application or operating environment.

Abstract: The present invention discloses a GPS system that uses call-processor intelligence to determine the mode of operation of a GPS receiver located in a GPS terminal. The modes are selected based on the availability of network facilities, the GPS information that can be acquired, or user input requirements.

Abstract: Systems and methods for mitigating multipath signals in a receiver are provided. In this regard, a representative system, among others, includes a receiver comprising an antenna being configured to receive signals from a plurality of satellites, and a computing device being configured to: generate pseudorange measurements based on the received satellites signals, process the generated pseudorange measurements to reduce its pseudorange residuals based on statistical modeling in order to mitigate multipath errors, and compute navigation solutions based on the processed pseudorange measurements. A representative method, among others, for mitigating multipath signals in a receiver, comprises: receiving the pseudorange measurements; processing the received pseudorange measurements to reduce its pseudorange residuals based on statistical modeling in order to mitigate multipath errors; and computing navigation solutions based on the processed pseudorange measurements.

Abstract: A system and method for providing temperature compensation in a oscillator component (such as a crystal oscillator component) that includes a closely-located temperature sensing device. The crystal oscillator component in example systems and methods is exposed to a temperature profile during a calibration procedure. Temperature and frequency data are collected and applied to coefficient generating function according to a temperature compensation model to generate a set of coefficients that are used in the temperature compensation model in an application device. The generated coefficients are stored in a coefficient memory accessible to an application device during operation.

Abstract: A frequency domain diversity DVB receiver device includes multiple antenna ports for receiving radio signals, and radio signal processing circuits connected to the antenna ports that convert the received radio signals into digital samples. The digital samples from the different antenna ports time-share a front-end processor which processes the digital samples to provide time-domain symbols. The time-domain symbols are stored in time-domain symbol buffers according to which of the antenna ports the time-domain symbols are received. A fast fourier transform circuit then retrieves the time-domain symbols and converts them frequency-domain symbols, which are then stored one or more frequency-domain symbol buffers according to the antenna ports the corresponding radio signals are received. A diversity processor which combines the frequency-domain symbols from the frequency-domain symbol buffers.

Abstract: The present invention discloses a method and apparatus for allowing for GPS receiver functions and GPS digital processing functions to co-exist and function optionally or nearly optimally while in close proximity on a common die.