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: A highly integrated GPS RF Front End which uses a single conversion stage employs an image rejection mixer stage to eliminate the need for an image reject RF bandpass filter. Also a relatively high sample rate A/D is employed which allows a timeless monolitic IF Filter to be used. The disclosure also discusses a GPS Front End topology that is easily integrated from industry standard building blocks. With the broad variation in potential receiver designs, the present invention includes some specific receiver topologies that lend themselves to a high level of integration. The specific designs presented here are comprised of industry standard building blocks and functions that have been described elsewhere in the related art.

Abstract: A wireless apparatus includes an electrically conductive casing housing a ground plane and GPS receiver circuitry. The casing is electrically connected to the ground plane to form a first antenna element. The apparatus further includes a second antenna element located external the casing. The second antenna element may be configured as a wire filament in the form of a copper trace carried by a printed circuit board. The second antenna element is electrically coupled to the first antenna element and the GPS receiver circuitry. The first antenna element and second antenna element are configured and disposed relative to each other to form an antenna for receiving GPS signals.

Abstract: A signal detector employs a coherent accumulation system that coherently combines the correlation results derived from segments of samples of a received signal. The segments may have non-uniform lengths and may have been obtained over different and non-overlapping time periods. The segments are obtained during sampling windows of arbitrary length and at arbitrary times, and the results of processing the segments are successively combined in a coherent manner (separate magnitude and phase accumulation) until a threshold signal-to-noise ratio (SNR) has been achieved. Coherent integration is enabled by introducing a carrier phase offset as well as a code phase offset, so that different segments are aligned in carrier phase as well as code phase. Although not limited to this application, in one implementation example, the signal detector is used in connection with and as part of a global positioning system (GPS) receiver.

Abstract: A method in a Global Positioning System (GPS) receiver achieves enhanced performance by scheduling searches in the Doppler search space according to a cost function. The cost function relates to both the cost of building a 3-dimensional correlation grid and the cost of searching satellite, code phase, Doppler and integration time interval spaces for values that provide a maximum in the correlation grid. In one embodiment, after the clock Doppler is determined upon acquiring one satellite, the Doppler search range associated with a cell in the grid is dominated by the receiver's own motion. The scheduler schedules searching of the Doppler search space using search ranges determined empirically by the expected receiver velocity. In one embodiment, the scheduler increases integration times before changing Doppler search ranges, which require a recalculation of the grid.

Abstract: System and method to determine the location of a receiver are provided. The received signal is decomposed into signal chunks that are then correlated with the reference signals of the transmitting sources. In some embodiments, the signal chunks may be shorter than the period of the reference signals. For each signal source, a grid of correlation values is constructed containing one column of correlation values for each signal chunk. Each column contains correlation values for several code-phases. Probes are executed in the grid to acquire the location-determining signals. In some embodiments, a probe includes calculating the fourier transform of a row in the grid, yielding correlation values associated with a refined set of frequency values. Potential acquisitions are verified by processing increasing portions of the received signal. Confirmed acquisition may be used to aid further acquisitions.

Abstract: System and method for mitigating the effects of narrowband noise in a location-determining signal are provided, wherein the location-determining signal is associated with a periodic reference signal, the embodiments include identifying a set of noisy frequencies in the signal, determining a set of frequencies to be removed, and removing the set of frequencies from either the location-determining signal or the reference signal, thereby removing the effects of narrowband noise from the location-determining signal.

Abstract: The invention is directed to a personal communications device with a ratio counter providing tracking transitioning edges of two clocks so as to generate a signal to initiate capture of a clock cycle count. Provisions for tracking the transitioning edges include a storage memory for storing a first and a second value selected in accordance with the principles of convergents of continued fractions. A first and second counter each responding to first and second clock signal, respectively. The first and second counter each count clock cycles of the respective clock signal. A first register for capturing the count of the first counter and a second register for capturing the count of the second counter.

Abstract: A spread spectrum receiver processes signals from a plurality of sources modulated by different spread spectrum codes by sampling the signals as received to produce an integer series of sampling segments at a sampling rate at least twice a chip rate of the codes, each sampling segment containing an integer number of bits representing a fraction of a chip of the codes, time division multiplexing each sample segment into a number of channels, correlating the bits in each sample segment in each channel in parallel with a source specific series of locally generated sequential code samples differing by one bit, summing each parallel correlation, and accumulating the summed parallel correlations for each code sample in each channel at a rate at least equal to the chip rate to derive data related to each of the sources.

Abstract: Upon reception of four GPS signals from GPS satellites and determining four pseudo ranges, along with ephemeris data previously stored in the GPS receiver, the location of the GPS receiver and real time clock time error is determined. The GPS receiver is in possession of four pseudo ranges and determines four unknown coordinate values (x, y, x, and time) identifying the location of the GPS receiver and real time clock error. The process of solving for four pseudo range formulas simultaneously with each pseudo range formula having an unknown “x”, “y” “z”, and time coordinates of the GPS receiver, results in identification of the coordinates and time of the GPS receiver. In a similar process, the GPS receiver receiving four GPS signals from four GPS satellites is able to determine four pseudo ranges. Using the four pseudo ranges, four pseudo range equations unknown values for “x”, “y”, “z” and time can be solved for simultaneously.

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 method for providing an initial estimate for an interval of possible values for a parameter used in an acquisition of a signal maintains parameter values obtained from previous signal acquisitions and the times at which the signal acquisitions were made. The maintained values of the parameter are used to derive a candidate value for the parameter to be used in a new signal acquisition. To make the maintained values available even after a brief period during which the GPS receiver is powered down, the maintained values can be stored in a non-volatile memory. The signal acquisitions may correspond to GPS satellite signal acquisitions, and the maintained parameter values can be grouped according to whether a successful receiver location determination was accomplished.

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: 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: 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: A multi-function device with a positioning function and a real time positioning engine is disclosed. The device contains also a shared processor used by the positioning function and other functions of the device, such as a mobile radio-communication function. The positioning engine performs in real time the most computational intensive calculations of the positioning function, such as downsampling, Doppler mixing and correlation calculations. Since the received signal need not be stored, the memory requirements of the positioning function are significantly reduced if aiding data is available.

Abstract: In a mobile communication device, a method for compensating for a frequency adjustment in an oscillator shared between a communication circuit and a positioning signal receiver is provided. In one embodiment, the method begins to receive and store a positioning signal at a first time point. When, at a second time point, the operating frequency of the shared oscillator is adjusted, the frequency adjustment is recorded. After the positioning signal is completely received and stored, the processing of the positioning signal takes into consideration the frequency adjustment. In that embodiment, the processing hypothesizes a frequency shift in the received positioning signal. According to another aspect of the present invention, a method for determining the operating frequency of an oscillator detects a beginning time point of a reference signal received by the mobile communication device and enables a counter to count in step with a clock signal derived from the oscillator.

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 combined Global Position System (“GPS”) and radio system for receiving GPS signals and radio signals is disclosed. The combined GPS and radio system includes a controller that controls a switchable frequency source and a mixer in signal communication with the switchable frequency source. The mixer is capable of receiving both GPS signals and radio signals and producing corresponding intermediate frequency (“IF”) signals in response to receiving a frequency reference signal from the switchable frequency source that has a first switch state of operation that corresponds to the mixer receiving GPS signals and a second switch state of operation the corresponds to the mixer receiving radio signals.

Abstract: A data detection circuit within a global positioning system (GPS) satellite receiver operates to detect and decode data sent in a spread spectrum signal. The data detection circuit receives input from a radio receiver, the information containing data from a plurality of satellites. The data is supplied to a circular memory device, which determines which data corresponds to which satellite. The memory device sends the received signal to a matched filter, which decodes the signal received from each satellite. This signal is analyzed to determine whether a phase inversion due to data modulation on the received signal is present. The phase inversion can occur at boundaries, known as data epochs, in the received signal, and corresponds to data in the received signal. This data contains information relating to the position of each satellite and is collected by the data detection circuit for use by the GPS receiver.