Abstract: A multi-standard GNSS receiver, handle different global navigation satellite systems (GNSSs), determines with respect to a current time instant, the earliest broadcast timing based on corresponding satellite broadcast cycles for satellites in the different GNSSs. The multi-standard GNSS receiver acquires fresh broadcast ephemeris at the determined earliest broadcast timing to determine its own first position. A search order is determined based on the corresponding satellite broadcast cycles and the current time instant. The multi-standard GNSS receiver may selectively utilize appropriate satellite receivers such as the GPS receiver and the GLONASS receiver to search for satellite signals based on the determined search order. Channels for different GNSSs are scanned to identify transmitting satellites based on the corresponding satellite broadcast cycles for ephemeris downloading. The satellite search is prioritized by comparing the current time instant with the corresponding satellite broadcast cycles.

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 processing long term orbit data that is valid for an extended period of time into the future (i.e., long term orbit data). The long term orbit data is processed by reducing redundant information from the data to form compressed long term orbit data.

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 first difference between a first time reference frame of the first satellite navigation system and a time reference and a second difference between a second time reference frame of the second satellite navigation system and the time reference are obtained. The at least one first pseudorange and the at least one second pseudorange are combined using the first and second differences in time references.

Abstract: Aspects of a method and system for keeping a device for satellite navigation in a state that enables rapid signal acquisition are provided. The device may acquire broadcast ephemeris from one or more satellite signals during a data refresh operation. The satellite signals may comprise a GPS signal, a GLONASS signal, a GALILEO signal, or a combination thereof. The device may compute extended or future ephemeris from the acquired broadcast ephemeris during the data refresh operation. In a positioning operation that is subsequent to the data refresh operation, the device may determine satellite navigation information from the computed extended ephemeris. In some instances, a time associated with a schedule of the data refresh operation may be adjusted based on the computed extended ephemeris. The extended ephemeris may be computed by integrating current and/or historic broadcast ephemeris into an orbit model.

Abstract: A method and apparatus for determining long term orbit (LTO) models using variable time-horizons to improve the orbit and clock model accuracy. The method and apparatus use either historic ephemeris or historic measurements for at least one satellite to produce an orbit parameter prediction model (an LTO model). The parameter predicted by the model is compared to an orbit parameter of a current broadcast ephemeris. The result of the comparison (an indicia of accuracy for the model) is used to establish a time-horizon for the orbit parameter prediction model for that particular satellite. Such a time-horizon may be established in this manner for each satellite within a satellite constellation.

Abstract: A GNSS receiver in a wake up state during a standby mode may acquire ephemeris from received GNSS signals such as GPS signals and/or GLONASS signals. When subsequently transitioning from the standby mode to a normal mode operating at a high frequency clock, the acquired ephemeris may be utilized to generate a navigation solution for the GNSS receiver. The GNSS receiver in the wake up state during the standby mode may be switched to operate at the high frequency clock in order to receive GNSS signals. The GNSS receiver may extract complete ephemeris from the received GNSS signals, and may subsequently transition from the wake up state to a sleep state during the standby mode to save power. Radio frequency front-end components of the GNSS receiver may only be turned on to receive the GNSS signals. The GNSS receiver may transition between the standby mode and the normal mode.

Abstract: Method and apparatus for processing satellite signals in an SPS receiver is described. In one example, the satellite signals are correlated against pseudorandom reference codes to produce correlation results. A determination is made whether the SPS receiver is in a motion condition or a stationary condition. The correlation results are coherently integrated in accordance with a coherent integration period. The coherent integration period is a value that depends upon the motion condition of the SPS receiver.

Abstract: A GNSS enabled mobile device concurrently receives GNSS signals from GNSS satellites and transmissions from a cellular base station. GNSS-based velocities and GNSS locations are determined for the GNSS enabled mobile device utilizing the received GNSS signals. A cellular Doppler is measured on the cellular base station. A location of the cellular base station is determined based on the determined GNSS-based velocity and corresponding cellular Doppler measurements. The cellular base station may be located by the GNSS enabled mobile device and/or by a remote location server. In this regard, the remote location server may determine the location for the cellular base station utilizing GNSS velocities and corresponding cellular Doppler measurements received from plural GNSS enabled mobile devices in a coverage area of the cellular base station. The determined location of the cellular base station is used to refine GNSS locations of the plurality of GNSS enabled mobile devices when needed.

Abstract: Method and apparatus for validating an initial position in a satellite positioning system using range-rate measurements is described. In one example, range-rate measurements are obtained at the remote receiver with respect to a plurality of satellites. Expected range-rates are computed with respect to the plurality of satellites using the initial position. Single differences are computed using the range-rate measurements. Expected single differences are computed using the expected range-rates. Single difference residuals are computed between the single differences and the expected single differences. The single difference residuals are compared to a threshold. The initial position may be deemed valid if the absolute value of each of the single difference residuals is less than or equal to the threshold. A valid initial position may be used to fix the pseudorange integers.

Abstract: Method and apparatus for computing position using instantaneous Doppler measurements from satellites is described. In one example, instantaneous Doppler measurements are measured for a plurality of satellite signals relative to a satellite signal receiver. The instantaneous Doppler measurements are transmitted to a server. Position of the satellite signal receiver is computed at the server using the instantaneous Doppler measurements. In another example, at least one fractional pseudorange is measured between the satellite signal receiver and a respective at least one satellite. At least one instantaneous Doppler measurement is measured for a respective at least one satellite signal relative to the satellite signal receiver. The at least one pseudorange and the at least one instantaneous Doppler measurement are sent to a server. Position of the satellite signal receiver is computed at the server using the at least one pseudorange and the at least one instantaneous Doppler measurement.

Abstract: A GNSS enabled mobile device receives GNSS assistance data comprising acquisition assistance data, from an A-GNSS server and calculates a relative GNSS position using the receive acquisition assistance data and a local code delay measurement, without using ephemeris data. The received GNSS assistance data comprises an approximate position, acquisition assistance data, satellite almanac data, and/or satellite azimuth and elevation fields, but no ephemeris data. The A-GNSS server calculates corresponding acquisition assistance data at a current time instant and/or one or more future time instants for the approximate position. The satellite azimuth and elevation fields are calculated using local GNSS measurements together with the acquisition assistance data in the received GNSS assistance data are used to calculate the relative GNSS position, which is added to the approximate position to generate an actual GNSS position.

Abstract: A method and apparatus for maintaining integrity of long-term-orbit information used by a Global-Navigation-Satellite-System or other positioning receiver is described. The method comprises obtaining a predicted pseudorange from a first set of long-term-orbit information possessed by a positioning receiver; obtaining, at the positioning receiver from at least one satellite, a measured pseudorange; determining validity of the predicted pseudorange as a function of the predicted pseudorange and the measured pseudorange; and excluding from the long-term-orbit information at least a portion thereof when the validity of the predicted pseudorange is deemed invalid. Optionally, the method may comprise updating or otherwise supplementing the long-term-orbit information with other orbit information if the validity of the predicted pseudorange is deemed invalid.

Abstract: Aspects of a method and system for maintaining a GNSS receiver in a hot-start state are provided. A GNSS receiver in a standby mode may transition from a sleep state to a wakeup state to acquire ephemeris from, for example, GPS signals, GALILEO signals, and/or GLONASS signals. The acquired ephemeris may be stored and utilized for the GNSS receiver to generate a navigation solution in a normal mode. The GNSS receiver may transition from the normal mode to the sleep state or the wakeup state in standby mode. A sleep period and a wakeup period for the full sleep-wakeup cycle in the standby mode may be predetermined or dynamically adjusted based on required QoS, quality of satellite signals, and/or user inputs. The sleep period and the wakeup period may be selected in a way to ensure a valid and complete ephemeris to be acquired.

Abstract: Method and apparatus for validating an initial position in a satellite positioning system using range-rate measurements is described. In one example, range-rate measurements are obtained at the remote receiver with respect to a plurality of satellites. Expected range-rates are computed with respect to the plurality of satellites using the initial position. Single differences are computed using the range-rate measurements. Expected single differences are computed using the expected range-rates. Single difference residuals are computed between the single differences and the expected single differences. The single difference residuals are compared to a threshold. The initial position may be deemed valid if the absolute value of each of the single difference residuals is less than or equal to the threshold. A valid initial position may be used to fix the pseudorange integers.

Abstract: A method and apparatus for determining time-of-day in a mobile receiver is described. In one example, expected pseudoranges to a plurality of satellites are obtained. The expected pseudoranges are based on an initial position of the mobile receiver and an initial time-of-day. Expected line-of-sight data to said plurality of satellites is also obtained. Pseudoranges from said mobile receiver to said plurality of satellites are measured. Update data for the initial time-of-day is computed using a mathematical model relating the pseudoranges, the expected pseudoranges, and the expected line-of-sight data. The expected pseudoranges and the expected line-of-sight data may be obtained from acquisition assistance data transmitted to the mobile receiver by a server. Alternatively, the expected pseudoranges may be obtained from acquisition assistance data, and the expected line-of-sight data may be computed by the mobile receiver using stored satellite trajectory data, such as almanac data.

Abstract: Method and apparatus for decoding a bitstream of navigation data broadcast by a satellite positioning system satellite is described. In one example, a portion of a subframe in the navigation data for each of a plurality of occurrences of the subframe in the bitstream is obtained at a satellite signal receiver to produce a respective plurality of subframe portions. The subframe portions are then combined to recover the subframe. The subframe portions may be processed to maintain a constant polarity by comparing a common sequence of data bits among at least two of the subframe portions to identify a mismatch in polarity.

Abstract: A GNSS enabled mobile device receives GNSS signals from visible GNSS satellites. Broadcast ephemeris is extracted from the received GNSS signals for generating ephemeris extension (future ephemeris) in the next several days for each of the visible GNSS satellites. The GNSS enabled mobile device uses the generated future ephemeris to determine a position fix even without fresh broadcast ephemeris completely received from the visible GNSS satellites. The generation of future ephemeris is scheduled according to the age of available ephemeris extensions and/or the time of visibility. Available ephemeris such as extracted broadcast ephemeris are integrated into an orbit model using the multi-step numerical integration methods and propagated to generate future ephemeris. The generated future ephemeris is reformatted into a desired orbit model and/or format of the GNSS enabled mobile device.

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 determining time-of-day in a mobile receiver is described. In one example, expected pseudoranges to a plurality of satellites are obtained. The expected pseudoranges are based on an initial position of the mobile receiver and an initial time-of-day. Expected line-of-sight data to said plurality of satellites is also obtained. Pseudoranges from said mobile receiver to said plurality of satellites are measured. Update data for the initial time-of-day is computed using a mathematical model relating the pseudoranges, the expected pseudoranges, and the expected line-of-sight data. The expected pseudoranges and the expected line-of-sight data may be obtained from acquisition assistance data transmitted to the mobile receiver by a server. Alternatively, the expected pseudoranges may be obtained from acquisition assistance data, and the expected line-of-sight data may be computed by the mobile receiver using stored satellite trajectory data, such as almanac data.