| Patent application number | Description | Published |
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| 20080270026 | METHOD AND APPARATUS IN POSITIONING WITHOUT BROADCAST EPHEMERIS - 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. | 10-30-2008 |
| 20080303713 | NAVIGATIONAL POSITIONING WITHOUT TIMING INFORMATION - 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. | 12-11-2008 |
| 20090002226 | POSITION AND TIME DETERMINATION UNDER WEAK SIGNAL CONDITIONS - 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. | 01-01-2009 |
| 20090237300 | SYSTEMS AND METHODS OF COMMUNICATION IN AN ASSISTED NAVIGATION SYSTEM - Provided herein are methods and systems for efficient communication between a server and a client in an assisted navigation system. In one or more embodiments, the client, e.g., a GPS receiver, receives a set of parameters for a satellite from the server via a wireless or wired connection. The set of parameters includes a force parameter, initial condition parameters and time correction coefficients for the satellite. The receiver uses the received parameters in a numerical integration to compute the position of the satellite at a desired time. The set of parameters needed for the integration is small compared to current methods which require sending more data to the client. Thus these parameters require less communication resources to transmit. To further reduce the amount of data that needs to be transmitted, reference parameters may be subtracted from the original parameters before transmission from the server. The receiver is able to reconstruct the original parameters from the received parameters and the identically computed reference parameters. The parameters may be further compressed using data compression techniques. | 09-24-2009 |
| 20090254279 | Compensation for mounting misalignment of a navigation device - Compensating for the misalignment of a navigation device with respect to a vehicle is described. In one example, the compensation is made by applying a high pass filter to a measured acceleration of the vehicle to produce a motion acceleration signal, weighting the motion acceleration signal with a measured steering rate of the vehicle, and deriving misalignment parameters for the navigation device with respect to the vehicle using the weighted motion acceleration signal. | 10-08-2009 |
