Abstract: The present invention discloses a system for determining the position of a GPS terminal. The system comprises a GPS terminal, a location aiding server, and a communications system. Messages are passed between the GPS terminal and the server, as well as within the GPS terminal, to determine the mode of operation of the GPS portion of the system. Decisions are made based on availability of aiding data and Quality of Service requirements.

Abstract: An Aided Location Communication System (“ALCS”) is described that may include a geolocation server and a wireless communication device having a GPS section where the GPS receiver section is capable of being selectively switched between a standalone mode and at least one other mode for determining a geolocation of the wireless communications device. An Aided Location Communication Device (“ALCD”) is also described. The ALCD includes a position-determination section having a GPS receiver and a communication section where the position-determination section is selectively switchable between a GPS-standalone mode and at least one other mode for determining a geolocation of the ALCD.

Abstract: A variable code-tracking loop filter in a receiver having the ability to change its parameters multiple times in response to received signals. Parameters for the code-tracking loop filter may be varied based on phase and frequency errors from an error detector. In one implementation, the code-tracking loop filter is able to repeatedly vary a single parameter, such as its received bandwidth, based on the phase and frequency errors, while in another, the code-tracking loop filter may vary two or more parameters, such as the loop bandwidth and the natural frequency.

Abstract: A software communication device with a tunable transceiver that is capable of receipt of both satellite positioning data and a communication network with a wireless network where positioning data is used to efficiently make a connection to the communication network or communication link to a network is used to reduce the time to acquire GPS satellites and determine position.

Abstract: A GPS RF Front End IC using a single conversion stage, which is immune from self jamming from clock signal harmonics generated internally or from dominant clock signal harmonics generated externally by the subsequent baseband GPS processor which uses a clock of 48?fo for GPS processing. The improved frequency plan reduces the problems of interference when the integration of the RF and Baseband functions is required in the form of a single-chip, or as 2 individual chips on a common substrate.

Abstract: Systems and methods are disclosed herein for using a switched mode TCXO or VC-TCXO in a satellite navigation receiver where the switched mode TCXO or VC-TCXO may operate either in an active compensation mode to compensate for temperature induced frequency error or in a second fixed compensation mode where the TCXO or VC-TCXO is not compensated for temperature. The switched mode TCXO or VC-TCXO is operated in the active compensation mode when satellite acquisition performance may be improved from a reduction in the range of oscillator frequency error. The switched mode TCXO or VC-TCXO may be switched to operate in the fixed compensation mode when satellite tracking performance is sensitive to discontinuities in the phase, frequency, and/or frequency rate of the oscillator clock when temperature compensation is applied.

Abstract: A frequency phase correction system and method are described that provides a receiver with a greater ability to lock onto relatively weak radio frequency signals by determining and estimating an amount of frequency error in a local frequency reference of the receiver, and using the error estimate to maintain frequency coherence with a received signal, thereby allowing tracking over a longer period of time, enabling longer integration times to capture weaker signals without losing frequency coherence.

Abstract: The present invention is related to location positioning systems, and more particularly, to a method and apparatus of synchronizing to data frames in a positioning system signal. According to one aspect, the invention speeds up the frame synchronization process by computing a frame synchronization metric for each satellite and then combining together the metrics for all tracked satellites together, after compensating for respective signal transit times. Then the invention makes a frame sync decision on the combined satellite metric. In embodiments, an optimal combining algorithm is used based on CNO of each satellite. According to further aspects, the invention further speeds up the frame synchronization process by predicting many bits in the subframe so that more bits are known in addition to the 8-bit preamble. For example, the invention recognizes that many bits in a subframe rarely change or don't change very often. Moreover, the invention uses old ephemeris used to predict new ephemeris parameters.

Abstract: Synchronizing a Radio Network with End User Radio Terminals A Mobile Station that is able to receive GPS signals and compare the frequency of the GPS received time signal with a time signal from a network in order to determine the difference between the signals and communicate that difference back to the network.

Abstract: The present invention determines those mathematical processes that are repeated in the standard search schema, and uses this information to simplify the process by eliminating repetition of processes that have already been performed. The present information can be implemented in standard circuitry and with fewer instructions than the standard approach. As such, the present invention allows for receiver implementations that are of lower cost and lower power consumption, while achieving the same functionality as the standard receiver topology. The present invention achieves these goals by forming a lookup table of partial accumulations, and presents a method to efficiently address these partial accumulations for use during the accumulation and correlation processes performed by the receiver. These partial accumulations are in turn added together, or accumulated, to form the total accumulation over the desired time period.

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: The present invention provides systems and methods for downloading navigation data to a satellite receiver under weak signal conditions. In an embodiment, the receiver uses a tracking algorithm to estimate the Doppler frequency and rate of change of the Doppler frequency to compensate the phases of the I/Q samples from the received signal to reduce the effect of the Doppler frequency. In an embodiment, differential detection based data bit decoding is provided. In another embodiment, phase compensation based data bit decoding is provided, in which the phase of samples are rotated to compensate for phase error. In an embodiment, a multiple frame strategy is provided to increase signal-to-noise ratio (SNR) and improve sensitivity, in which similar placed samples in consecutive frames are coherently summed over the consecutive frames. In an embodiment, the samples are weighted to reduce the impact of noise in the multiple frame strategy.

Abstract: A method for estimating a Doppler spread and a signal-to-noise ratio of a received signal includes: (a) calculating one or more functions of a carrier component of the received signal at a first time point relative to a pilot signal embedded in the received signal; (b) Calculating the one or more functions of the carrier component of the received signal at a second time point relative to the pilot signal; (c) repeating steps (a) and (b) over multiple time periods, each time period being substantially longer than the second time, and accumulating the one or more functions for the first time points and the second time points; and (d) Deriving the Doppler spread and the signal-to-noise ration based on the accumulated one or more functions calculated at the first and second time points. In one embodiment, the first time point is substantially closer to the pilot signal than the second time point. The first time point is one symbol interval from the pilot signal.

Abstract: Systems and methods for minimizing electromagnetic interference are provided. A representative electronic device includes a frequency generator that generates clock signals and a computing device that selects at least one generator frequency that minimizes or eliminates electromagnetic interference based on one or more radio bands of interest. The computing device is designed to send instructions associated with synthesizing the at least one generator frequency. The electronic device further includes a frequency synthesizer that receives the generated clock signals and instructions from the frequency generator and the computing device, respectively. The frequency synthesizer synthesizes the at least one generator frequency based on the received clock signal.

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. The tracker hardware interface receives positioning information from the space vehicle tracker. The host based positioning system also includes a memory that includes a GPS library having a user interface, a tracker interface, and an operating system interface. A processor runs functions provided by the interfaces.

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: The present invention discloses a method and system for monitoring a wireless network clock compared to an absolute time scale using the user mobile stations themselves. The major advantage is the capability to transfer GPS time to a Mobile Station in a wireless network, and thus to decrease the time necessary for the mobile receiver to perform position calculations, with minimal additional hardware required by the network.

Abstract: Provided herein are methods and system for enabling a navigation receiver to generate receiver specific satellite orbital models based on relatively small sets of parameters obtained from a server. In an embodiment, a set of parameters for a satellite includes a force parameter (e.g., solar radiation pressure), initial condition parameters (e.g., satellite position and velocity at a time instance) and time correction coefficients, which the receiver uses in a numerical integration to predict the position of the satellite. The set of parameters needed for the integration is small compared to current methods which require transmission of a complete set of ephemeris and other parameters for each satellite. Since the set of parameters is relatively small, it requires less communication resources to transmit compared to current methods. Further, the integration based on the small set of parameters enables the receiver to predict satellite orbits with low computational load.

Abstract: The present invention provides an elevation based adaptive scheme for setting power threshold in the acquisition of navigational satellite signals. In an embodiment, the elevation based adaptive scheme uses a different series of power thresholds to acquire signals from satellites at different elevation angles instead of using one threshold for all satellites, as is done in the prior art. This scheme exploits the fact that the received signal power level depends on the elevation angle of the satellite at the receiver. This scheme also takes into account the antenna gain variation without having to measure the antenna gain variation.

Abstract: The present invention provides systems and methods for enabling a navigation signal receiver to perform both data assisted and non-data assisted integration to provide better integration during signal acquisition, reacquisition and tracking. In data assisted integration mode, a receiver uses known or predicted data bits to remove the modulated data bits of a received signal prior to integration. In non data assisted integration mode, when the data bits are not known or predictable, the receiver uses an optimal estimation or maximum likelihood algorithm to determine the polarities of the modulated data bits of the received signal. This may be done by determining which of various possible bit pattern yields the maximum integrated power. When the modulated data bits are not known or predictable over a limited range, the receiver carries out data assisted integration over the known or predictable data bits and additional non data assisted integration.