Abstract: A method and apparatus for compensating an oscillator in a location-enabled wireless device is described. In an example, a mobile device includes a wireless receiver for receiving wireless signals and a GPS receiver for receiving GPS signals. The mobile device also includes an oscillator having an associated temperature model. A frequency error is derived from a wireless signal. The temperature model is adjusted in response to the frequency error and a temperature proximate the oscillator. Frequency error of the oscillator is compensated using the adjusted temperature model. In another example, a frequency error is derived using a second oscillator within the wireless receiver.

Abstract: Method and apparatus for locating position of a mobile device in an assisted satellite positioning system is described. In one example, satellite measurement data is obtained from a plurality of satellites at a mobile device. Position of the mobile device is computed using the satellite measurement data. The position is sent to a cellular device via a wireless ad hoc network. In one example, the wireless ad hoc network comprises a BLUETOOTH communication link. In one example, the mobile device is configured to receive assistance data from a position server through the wireless ad hoc network. For example, the mobile device may comprise a housing configured to plug into a cigarette lighter connector of an automobile and the cellular device may comprise a cellular telephone without location-determination capabilities (i.e., the cellular telephone does not include an integrated GPS receiver).

Abstract: A method and apparatus for distribution and delivery of global positioning system (GPS) satellite telemetry data using a communication link between a central site and a mobile GPS receiver. The central site is coupled to a network of reference satellite receivers that send telemetry data from all satellites to the central site. The mobile GPS receiver uses the delivered telemetry data to aid its acquisition of the GPS satellite signal. The availability of the satellite telemetry data enhances the mobile receiver's signal reception sensitivity.

Abstract: A method and apparatus for monitoring the integrity of satellite tracking data used by a remote receiver is described. In one example, a first set of satellite tracking data is received at a server. Integrity data for a second set of satellite tracking data is generated using the first set of satellite tracking data. The integrity data is then transmitted to at least one remote receiver having the second set of satellite tracking data.

Abstract: Methods and systems for measuring wireless signals are described. The method includes generating a velocity estimate that includes a speed and a direction of a wireless receiver. A change in the velocity estimate is detected and how frequently the wireless signal is measured is adjusted according to the change detected in the velocity estimate. Systems may include wireless receivers that include an accelerometer that is operable to generate a velocity estimate that includes speed and direction of the wireless receiver. The wireless receivers may also include a processor operable to adjust a measurement period of the wireless signal in the wireless receiver according to a rate of change in the velocity estimate.

Abstract: A method and apparatus for performing frequency analysis of sub-epoch correlations to estimate an unknown frequency of a received signal is provided. The method includes forming a sequence of correlation values from a plurality of correlations performed over a period less than a repeating period of a code, and analyzing the sequence of correlation values to estimate the frequency that is used to receive a signal comprising the code.

Abstract: A method and apparatus for selecting a signal processing resolution. A received signal is processed using a first resolution. When a multipath condition is detected, the signal is processed using a second resolution.

Abstract: A method and apparatus for computing position using a regional-terrain model is provided. The method includes obtaining from at least three satellites pseudorange measurements, computing a transitional position by using a default altitude with a large uncertainty, using this transitional position to obtain from a terrain model altitude information associated with a region, and computing an accurate three-dimensional position as a function of the pseudorange measurements and the altitude information. The region defines a boundary, and the boundary includes the transitional position.

Abstract: A method and apparatus for mitigating multipath effects in a satellite signal receiver is described. In one example, measured pseudoranges are obtained from the satellite signal receiver to a plurality of satellites. For each measured pseudorange: an expected pseudorange is derived from a sequential estimation filter in the satellite signal receiver. The measured pseudorange and the expected pseudorange are differenced to compute a pseudorange residual. The measured pseudorange is applied to the sequential estimation filter only if the pseudorange residual is within a window.

Abstract: A method and apparatus for computing position using a regional-terrain model is provided. The method includes obtaining from at least three satellites pseudorange measurements, computing a transitional position by using a default altitude with a large uncertainty, using this transitional position to obtain from a terrain model altitude information associated with a region, and computing an accurate three-dimensional position as a function of the pseudorange measurements and the altitude information. The region defines a boundary, and the boundary includes the transitional position.

Abstract: A method and apparatus for locating position of a GPS device is described. In one example, a method for provisioning a mobile device with a model for determining a position of the mobile device in at least one geographic area is provided. The method includes obtaining an estimate of the position of the mobile device, forming one or more satellite orbit models from the estimate and a wide area model, and sending the at least one satellite orbit model to the mobile device. The wide area model is formed from measurements from a plurality of satellites of a Global Positioning System, and the measurements are obtained by a plurality of reference stations.

Abstract: Method and apparatus for processing satellite signals from a first satellite navigation system and a second satellite navigation system is described. In one example, at least one first pseudorange between a satellite signal receiver and at least one satellite of the first satellite navigation system is measured. At least one second pseudorange between the satellite signal receiver and at least one satellite of the second satellite navigation system is measured. A difference between a first time reference frame of the first satellite navigation system and a second time reference frame of the second satellite navigation system, is obtained.

Abstract: Method and apparatus for locating position of a remote receiver is described. In one example, long term satellite tracking data is obtained at a remote receiver. Satellite positioning system (SPS) satellites are detected. Pseudoranges are determined from the remote receiver to the detected SPS satellites. Position of the remote receiver is computed using the pseudoranges and the long term satellite tracking data. SPS satellites may be detected using at least one of acquisition assistance data computed using a previously computed position and a blind search. Use of long term satellite tracking data obviates the need for the remote receiver to decode ephemeris from the satellites. In addition, position of the remote receiver is computed without obtaining an initial position estimate from a server or network.

Abstract: A method and apparatus for automatically deactivating an electronic device during flight of an aircraft. The method utilizes a global positioning system (GPS) or assisted global positioning system (AGPS) circuit to facilitate computing the acceleration, velocity and altitude of the electronic device and comparing this information to a profile to determine whether the acceleration, altitude and velocity meets a profile threshold of an airliner taking off. If the profile is that of the take-off of an aircraft, then the circuitry connected to the GPS/AGPS circuit will be deactivated.

Abstract: A method and apparatus for background decoding of a broadcast satellite-navigation message to maintain integrity of long-term-orbit information used in a Global-Navigation-Satellite System or other positioning system is described. The method may include processing the long-term-orbit information associated with at least one satellite to obtain a first position of a receiver; obtaining at least one portion of broadcast ephemeris transmitted from the at least one satellite; and processing, as a substitute for at least one portion of the long-term-orbit information, the at least one portion of broadcast ephemeris to obtain a second position of the receiver.

Abstract: A method of computing a correlation between a pseudorandom reference code and a satellite signal is provided. The method comprises receiving a satellite signal having a repeating code modulated thereon, wherein the satellite signal comprises a pseudorange; correlating the satellite signal with less than an entire length of the pseudorandom reference code with a portion of the satellite signal to produce a correlation over a period less than a period of the repeating code; and processing the correlation to form values representative of magnitude or power of the correlation to produce an energy signal.

Abstract: A method and apparatus for automatically deactivating an electronic device during flight of an aircraft. The method utilizes a global positioning system (GPS) or assisted global positioning system (AGPS) circuit to facilitate computing the acceleration, velocity and altitude of the electronic device and comparing this information to a profile to determine whether the acceleration, altitude and velocity meets a profile threshold of an airliner taking off. If the profile is that of the take-off of an aircraft, then the circuitry connected to the GPS/AGPS circuit will be deactivated.

Abstract: A method and apparatus for computing a convolution between a satellite signal from one of a plurality of satellite positioning systems and a pseudorandom code reference. The method and apparatus is capable of operating in multiple modes of resolution so as to enhance the sensitivity of the convolution processing.

Abstract: Method and apparatus for locating position of a remote receiver is described. In one example, long term satellite tracking data is obtained at a remote receiver. Satellite positioning system (SPS) satellites are detected. Pseudoranges are determined from the remote receiver to the detected SPS satellites. Position of the remote receiver is computed using the pseudoranges and the long term satellite tracking data. SPS satellites may be detected using at least one of acquisition assistance data computed using a previously computed position and a blind search. Use of long term satellite tracking data obviates the need for the remote receiver to decode ephemeris from the satellites. In addition, position of the remote receiver is computed without obtaining an initial position estimate from a server or network.

Abstract: A method and apparatus for computing position using a regional-terrain model is provided. The method includes obtaining from at least three satellites pseudorange measurements, computing a transitional position by using a default altitude with a large uncertainty, using this transitional position to obtain from a terrain model altitude information associated with a region, and computing an accurate three-dimensional position as a function of the pseudorange measurements and the altitude information. The region defines a boundary, and the boundary includes the transitional position.