Abstract: The technology disclosed teaches a method of improving accuracy of a GNSS receiver that has a non-directional antenna, with the receiver sending CDN a request for predictive data for an area that includes the receiver. Responsive to the query, the method includes receiving data regarding LOS visibility for the receiver with respect to individual satellites, and the receiver using the data for satellite selection, for choosing some and ignoring other individual satellites. Also disclosed is using the data to exclude from satellite selection at least one individual satellite based on lack of LOS visibility to the individual satellite. Further disclosed is recognizing and rejecting spoofed GNSS signals received by a GNSS receiver that has a non-directional antenna, in response to a CDN response to a request for predictive data for an area that includes the receiver, with the receiver comparing the data with measures of signals received from individual satellites.

Abstract: Disclosed is a method for achieving space-based autonomous navigation of global navigation satellite system (GNSS) satellites, and relates to the field of satellite navigation technologies. The method includes the following steps: optimizing a DRO, and establishing a dynamic model of an earth-moon space satellite orbit; establishing measurement links, by a low earth orbit (LEO) data relay satellite, with an earth-moon space DRO satellite and a GNSS respectively, and measuring an inter-satellite distance for modeling and linearization; adopting an extended Kalman filter (EKF) method to process inter-satellite measurement data, and autonomously determining a position and velocity of the global navigation satellite system without depending on the ground measurement and control support.

Abstract: Disclosed is a location information determining method and system for providing a variety of services based on a location. The location information determining method includes receiving cell information; and determining location information that matches the cell information as location information of a mobile terminal from a location information database that stores location information that matches a plurality of pieces of cell information, respectively.

Abstract: Methods and systems for methods and systems for performing GNSS orbit and clock augmentation and position determination are disclosed. In an embodiment, a method for performing GNSS augmentation and position determination includes obtaining orbit/clock initial parameters with a receiver device, generating a numerically-integrated orbit and extrapolated clock in response to the orbit/clock initial parameters with a processing device, and processing the observations of a GNSS receiver and the numerically-integrated orbit and extrapolated clock to derive an improved positioning solution with a processing device.

Abstract: A method and system for distributed messaging between a plurality of computer devices using a short range wireless communication protocol (SRWP) is disclosed. The communication protocol can be one in which slave devices provide data to master devices. A device automatically establishes master and slave connections with other devices via the protocol as they come into range. A user-entered message is displayed on the device and broadcast by the device over slave connections to other connected devices. Messages received by the device over its master connections are displayed and also rebroadcast to other connected devices. Messages can be displayed for a limited time period during which they fade or otherwise are altered to provide a visual indication of the display lifetime remaining for that message. A relay can be provided to receive an rebroadcast messages to connected devices and inject into the SRWP network from devices outside the network.

Abstract: In a method for detection of an anomaly related to information about a location of a mobile computing device, the anomaly related to the information about the location of the mobile computing device can be detected by a processor of the mobile computing device. A communication about the anomaly can be provided via a user interface of the mobile computing device. The anomaly can be caused by a bug in an operating system of the mobile computing device. Notifications about the anomaly can be provided to a user of the mobile computing device or other mobile computing devices registered to a shared account.

Abstract: Techniques are provided which may be implemented using various methods and/or apparatuses in a mobile device to determine its location. Techniques are provided which may be implemented using various methods and/or apparatuses on a mobile device to enable location determination during paging slots, wherein location is determined after both a location determination interval and the succeeding paging slot interval are complete. Determined location is stored and may be provided in response to requests from applications, application servers, location servers and for other purposes or entities.

Abstract: A device with transmitter broadcasts packets including a transmitter identifier via a radio interface with varying timings of transmissions. It determines a current timing of transmissions based on clock signals and a secret code, using a cryptographic function. A mobile device detects radio signals conveying such packets and performs measurements on the signals. It determines a currently used timing of transmissions, assembles a positioning request including the transmitter identifier, results of the measurements and an indication of the timing of transmissions, and transmits the request. A server receives the request. It generates for the transmitter an expected timing of transmissions using a cryptographic function, based on a signal of a master clock and based on a stored secret code assigned to the transmitter. It provides position information as trusted position information only in the case of a match between the indicated and the expected timing of transmissions.

Abstract: Systems and methods for inherent fast Time To First position Fix (TTFF) and high sensitivity are described. An embodiment of a method may include interpolating a satellite position in response to a navigation message having initial conditions for satellite ephemeris data converted into Keplerian format, wherein signal fixation is maintained in response to receiving the navigation signal at least once per day.

Abstract: Aspects of the disclosure include a method of prioritizing generation of predicted ephemeris data. The method includes receiving, by a device through a data network, first ephemeris seed data of a subset of a plurality of satellites, identifying a first satellite and a second satellite of the plurality of satellites, the first satellite being potentially detectable by the device at an estimated position at a given time, and the second satellite being potentially undetectable by the device at the estimated position at the given time, and prioritizing generation of first predicted ephemeris data that represent a first orbit of the first satellite before generation of second predicted ephemeris data that represent a second orbit of the second satellite. The generation of the first predicted ephemeris is based on the first ephemeris seed data.

Abstract: Disclosed is a location information determining method and system for providing a variety of services based on a location. The location information determining method includes receiving cell information; and determining location information that matches the cell information as location information of a mobile terminal from a location information database that stores location information that matches a plurality of pieces of cell information, respectively.

Abstract: An interface circuit in an electronic device may receive samples of wireless signals in a time interval, where the wireless signals are associated with the second electronic device. Then, the interface circuit may generate, based at least in part on the samples and a number of paths in a channel in a wireless environment of the electronic device, a signal spectrum corresponding to a set of estimated wireless-communication parameters. Moreover, the interface circuit may select a lower wireless-communication parameter in the set of wireless-communication parameters having an associated regression model with a fit to the signal spectrum that exceeds a statistical confidence threshold. Next, the interface circuit may identify, based at least in part on the selected lower wireless-communication parameter, samples of the wireless signal in the wireless signals associated with the line of sight between the electronic device and the second electronic device.

Abstract: A method of predicting the orbit of a satellite of a satellite positioning system, including: associating first and second types of satellites with first and second models of celestial mechanics forces, respectively; storing first ephemerides data of a satellite, associated to first time intervals and second ephemerides data associated to second time intervals. Further, the method comprises: calculating reference satellite positions based on the first ephemerides data; estimating first and second satellite positions in the first time intervals by using the second ephemerides data and the first and second forces models, respectively; determining first and second estimate errors by comparing the reference positions with the first and second positions, respectively; and detecting the type of satellite between the first and second types by an analysis of the first and second errors.

Abstract: Method, system, and device are provided for position determination with the use of predicted ephemeris to reduce the time-to-first-fix. The method includes: in a device, receiving broadcast orbit data and clock states from a plurality of satellites to determine first assistance data for the plurality of satellites, and numerically predicting first ephemeris for the plurality of satellites using the first assistance data. The method also includes: in a server system, receiving precise orbit data and accurate satellite clock states from a global GNSS service network to determine second assistance data; in a device, receiving the second assistance data and numerically predicting second ephemeris using the second assistance data.

Abstract: A method for reducing the positioning time of a GPS receiver is disclosed. In response to a request from a user function for positioning data, a GPS management section instructs a device control section to lower the functions of a group of components. The lowering of the functions of the components reduces the noise level. The GPS management section operates the GPS receiver. The GPS receiver executes an acquisition process in an environment with a low noise level. After completion of the acquisition process, the functions of the component are restored.

Abstract: Methods and apparatus for wireless communications are described. A method of wireless communications includes determining an energy for a first signal received at a first finger of a rake receiver after a reference signal is received at a second finger of the rake receiver, determining an energy for a second signal received at a third finger of a rake receiver before the reference signal is received at the second finger of the rake receiver, and selecting the first signal as a new reference signal when the energy of the first signal exceeds the energy of the second signal by a predefined threshold amount. In another aspect, a method includes assigning a signal received at a rake receiver to a finger of the rake receiver, and deassigning the finger if the signal has an energy level below a preselected lock threshold energy for a predefined time.

Abstract: Systems and methods are provided to determine launch parameters of satellites of a satellite constellation that provides optimized performance of the satellite constellation over the service lifetime of the satellite constellation. The launch parameters may be determined by considering perturbing accelerations of one or more of the satellites for the purposes of optimizing the launch parameters of the satellites of the satellite constellation. The systems and methods may include heuristic optimization and high-fidelity astrodynamic modeling methodologies.

Abstract: A reception control unit of an electronic timepiece includes a satellite-capturing control unit configured to search for a preferential search satellite more preferentially than the other position information satellites, the preferential search satellite being the position information satellite having a stored satellite number, a reception-state determining unit configured to determine, at timing of an end of the search for the preferential search satellite, whether a number of the captured position information satellites is equal to or larger than a predetermined number; a reception-stop control unit configured to stop a reception processing when the reception-state determining unit determines that the number of the position information satellites is smaller than the predetermined number; and a storage control unit configured to store the satellite number of the captured position information satellite in the satellite-number storing unit.

Abstract: Assisted-GPS for a portable biometric monitoring device is provided. The portable biometric monitoring device may obtain updated ephemeris data from an associated secondary device via a short-range, low-power communication protocol. The secondary device may be a computing device such as a smartphone, tablet, or laptop. Various rules may control when the ephemeris data is updated. The ephemeris data may be used in the calculation of the global position of the portable biometric monitoring device. Additionally, the portable biometric monitoring device may communicate downloaded position fixing data to the associated secondary device. The associated secondary device may then calculate the global position from the position fixing data.

Abstract: A method and system for assisting mobile stations to locate a satellite use an efficient messaging format. A server computes a correction between coarse orbit data of a satellite and precise orbit data of the satellite. A coordinate system is chosen such that variation of the correction is substantially smooth over time. The server further approximates the correction with mathematical functions to reduce the number of bits necessary for transmission to a mobile station. The mobile station, upon receiving the coefficients, evaluates the mathematical functions using the coefficients and a time of applicability (e.g., the current time), converts the evaluated result to a standard coordinate system, and applies the conversion result to the coarse orbit data to obtain the precise orbit data.

Abstract: A data model containing orbital parameters is stored in a mobile device. When a First Fix is required by a GNSS system within the mobile device, these stored orbital parameters are used to rapidly generate accurate satellite trajectory data model. The stored orbital parameters may be modified in part or in whole as required by changing coefficients of the stored parameters.

Abstract: Systems, methods and devices for improving the performance of Global Navigation Satellite System (GNSS) receivers are disclosed. In particular, the improvement of the ability to calculate a satellite position or a receiver position where a receiver has degraded ability to receive broadcast ephemeris data directly from a GNSS satellite is disclosed. Correction terms can be applied to an approximate long-term satellite position model such as the broadcast almanac.

Abstract: A method of predicting the orbit of a satellite of a satellite positioning system, including: associating first and second types of satellites with first and second models of celestial mechanics forces, respectively; storing first ephemerides data of a satellite, associated to first time intervals and second ephemerides data associated to second time intervals. Further, the method comprises: calculating reference satellite positions based on the first ephemerides data; estimating first and second satellite positions in the first time intervals by using the second ephemerides data and the first and second forces models, respectively; determining first and second estimate errors by comparing the reference positions with the first and second positions, respectively; and detecting the type of satellite between the first and second types by an analysis of the first and second errors.

Abstract: The present invention is related to location positioning systems, and more particularly, to a method and apparatus for providing an update of ephemeris information. According to one aspect, GPS enabled devices in the signal unavailable area monitors the state of its ephemeris data and time information. When the ephemeris data and time information become out of date, the GPS enable device uses an ad hoc Bluetooth network to retrieve ephemeris data and time information from another GPS enabled device with more current data. According to further aspects, a map of a deep hole region in which GPS and other cellular signals are not available, is generated to enable power reduction and cost saving measures.

Abstract: Accurate long term satellite models for satellites include satellites of different navigation systems. Such a model is derived for a non-GPS satellite that broadcasts native orbital model data specified as valid within a first time period. Initial position and velocity data are determined from the native orbital model data, and orbit integration is performed to determine an orbital arc in an earth-centered-earth-fixed frame over a second time period longer than the first time period. Initial estimates of GPS or GPS-like orbit parameters are determined for the non-GPS satellite, and the orbital arc and the initial estimates of the GPS or GPS-like orbit parameters are input to an orbit parameter solver that determines GPS or GPS-like parameters that fit the orbital arc and is used to determine final orbital model parameters in GPS or GPS-like format for the non-GPS satellite.

Abstract: A method of predicting a location of a satellite is provided wherein the GPS device, based on previously received information about the position of a satellite, such as an ephemeris, generates a correction acceleration of the satellite that can be used to predict the position of the satellite outside of the time frame in which the previously received information was valid. The calculations can be performed entirely on the GPS device, and do not require assistance from a server. However, if assistance from a server is available to the GPS device, the assistance information can be used to increase the accuracy of the predicted 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: An approach provides for conversion of global positioning system (GPS) data. A user terminal receives positioning data from a base station, wherein the positioning data is received in a second format, and wherein the second format was derived from ephemeris data broadcast via a global positioning system (GPS) in a first format. The user terminal converts the positioning data from the second format into a third format that is compatible with a protocol of the GPS system, and determines a first fix using the third format of the positioning data.

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 performs an update for a first device that consumes information with a known expiration time. The first device operates within a network that accommodates other devices also consuming the information. The method includes setting a time for the first device to refresh the information, the time to refresh being based on a pseudorandom time offset. The method also includes sending a refresh request to a resource for the data during the set time.

Abstract: A parameter calculating method includes: setting lengths of prediction target terms as divisions of a predetermined effective period of a satellite orbit as variable lengths; and calculating a parameter of a predetermined orbit model expression used for approximating the satellite orbit based on prediction position data containing prediction positions of a positioning satellite in time series for each of the prediction target terms.

Abstract: Methods and apparatus are described for processing a set of GNSS signal data derived from signals of GNSS satellites observed at reference station receivers, the data representing code observations and carrier observations on each of at least two carriers over multiple epochs, comprising: obtaining an orbit start vector comprising: a time sequence of predicted positions and predicted velocities for each satellite over a first interval, and the partial derivatives of the predicted positions and predicted velocities with respect to initial positions, initial velocities, force model parameters and Earth orientation parameters, obtaining ionospheric-free linear combinations of the code observations and the carrier observations for each satellite at multiple reference stations, and iteratively correcting the orbit start vector using at each epoch the ionospheric-free linear combinations and predicted Earth orientation parameters, as soon as the ionospheric-free linear combinations of the epoch are available, to ob

Abstract: Disclosed herein are methods and systems to help provide a location of a mobile station in cases in which the location of the serving base station may not be known or may not be available from a base station almanac. According to the disclosed methods and systems, if the serving base station is not listed in the almanac, a positioning system will direct the mobile station to obtain identification information from a second base station (e.g., the “second best” available base station) by acquiring or partially acquiring a connection to the second base station. The positioning system may then query the almanac for location information of the second base station, based on the identification information obtained from that base station.

Abstract: A method for real time subset geometry screening comprises the steps of determining a list of satellites in view of a ground based augmentation system in a navigation satellite system for a subsequent time interval in the future, defining at least one set of subset geometries from the list of available satellites, calculating a respective first ?vig for each of the at least one set of subset geometries, setting a respective broadcast ?vig for each set of subset geometries as the larger of the first ?vig and a second ?vig, wherein the second ?vig was calculated for the previous time interval, saving the first ?vig for a next iteration of the method, and selecting from the plurality of broadcast ?vig to match an available broadcast constellation. ?vig is a vertical ionosphere gradient standard deviation.

Abstract: A method of compensating for or correcting satellite ephemeris error involves measuring time difference of arrival (TDOA) and frequency difference of arrival (FDOA) for signal replicas received via two satellites (34, 46) from calibration transmitters (42a to 42d) at different geographical locations. An initial satellite ephemeris consisting of position and velocity vectors is used to calculate ephemeris changes yielding estimated TDOA and FDOA values providing a best fit to measured TDOA and FDOA values. This provides estimated changes required to compensate for or to correct errors in the initial satellite ephemeris. The method may be iterated to deal with large ephemeris changes: i.e. the changes obtained in one iteration may be used to correct ephemeris for use as a new initial ephemeris in a following iteration. The method may be used to correct ephemeris errors in one or both satellites, if so a greater number of calibration transmitters EphemCal 1 to EphemCal 10 may be used.

Abstract: A method comprising: receiving first information for defining a first algebraic function that relates a time variable to a first mapped variable; using the function to convert a time variable value to a first value of the first mapped variable e.g. s; converting the first value of the first mapped variable to a second value of a second mapped variable e.g. U; and positioning a satellite by converting the second value of the second mapped variable value to a position value that positions a satellite.

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: Methods, program products, and systems of location estimation using a probability density function are disclosed. In general, in one aspect, a server can estimate an effective altitude of a wireless access gateway using harvested data. The server can harvest location data from multiple mobile devices. The harvested data can include a location of each mobile device and an identifier of a wireless access gateway that is located within a communication range of the mobile device. The server can calculate an effective altitude of the wireless access gateway using a probability density function of the harvested data. The probability density function can be a sufficient statistic of the received set of location coordinates for calculating an effective altitude of the wireless access gateway. The server can send the effective altitude of the wireless access gateway to other mobile devices for estimating altitudes of the other mobile devices.

Abstract: A method, device and system for determining a receiver location using weak signal satellite transmissions. The invention involves a sequence of exchanges between an aiding source and a receiver that serve to provide aiding information to the receiver so that the receiver's location may be determined in the presence of weak satellite transmissions. With the aiding information, the novel receiver detects, acquires and tracks weak satellite signals and computes position solutions from calculated pseudo ranges despite the inability to extract time synchronization date from the weak satellite signals. The invention includes as features, methods and apparatus for the calibration of a local oscillator, the cancellation of cross correlations, a Doppler location scheme, an ensemble averaging scheme, the calculation of almanac aiding from a table of orbit coefficients, absolute time determination, and a modified search engine.

Abstract: Method and apparatus for managing a network element in a satellite navigation data distribution system is described. In one example, a network element includes a processor for processing satellite navigation data. For example, a network element may be a reference station, a hub, or a server in the satellite navigation data distribution system. The network element includes a memory for maintaining status variables associated with the processing of the satellite navigation data. The status variables may relate to the integrity of the satellite navigation data. The network element further includes a management agent for monitoring states of the status variables and communicating with a network management system to exchange information related to the states of the status variables. In one example, the management agent is configured to communicate using a simple network management protocol (SNMP).

Abstract: A method is disclosed for autonomously predicting satellite positions for the GPS and other satellite systems using the limited data processing capabilities of a typical embedded user device. The method involves a faster approach for performing initial element adjustments given previous position data. These adjusted initial elements are then used in the prediction calculations. The method may alternatively be used to obtain a fit to a precise orbit prediction of a satellite. A method of correcting a satellite orbit prediction is also disclosed.

Abstract: Method and apparatus for locating position of a satellite signal receiver is described. In one example, pseudoranges are obtained that estimate the range of a satellite signal receiver to a plurality of satellites. An absolute time and a position are computed using the pseudoranges at a first time. The absolute time is then used to compute another position at a subsequent time. In another example, a plurality of states associated with a satellite signal receiver are estimated, where the plurality of states includes a time tag error state. A dynamic model is then formed relating the plurality of states, the dynamic model operative to compute position of the satellite signal receiver.

Abstract: Systems and methods for enhanced broadcast ephemeris are described. These systems and methods include the calculation and transmission of globally and locally optimized parameters of the broadcast ephemeris of a global navigation satellite system, such as ionosphere, clock, and orbital parameters of a GPS satellite and receiver. The locally-optimized satellite clock parameter compensates for geographically-specific signal errors that cannot be compensated by any global parameter of the broadcast ephemeris. The enhanced broadcast ephemeris error corrections are transmitted in the conventional RINEX format.

Abstract: Systems, methods and devices for using ephemeris data in GNSS receivers and systems are provided. Receivers using synthetic ephemeris data for longer ephemeris availability under poor reception conditions are updated using a variety of techniques that allow for the transfer of accurate information onto degraded synthetic ephemeris information.

Abstract: Ephemeris data is downloaded intelligently to a GPS-enabled wireless communications device based on user activity rather than at fixed predetermined intervals. Ephemeris data can be downloaded to enable both Aided GPS and Assisted GPS. The device can download ephemeris data based on the frequency of requests into an API communicating with a GPS driver, based on the detection of a new network, or a change in time zone of the network time. Intelligent, adaptive downloading of ephemeris optimizes the usage of bandwidth and the data charge to the user while ensuring that ephemeris data is cached to provide assistance for location-based services such as turn-based navigation.

Abstract: The present invention is applicable to the field of GPS locating technologies and provides a method and an apparatus for locating a terminal device. The method includes: receiving information about starting a global positioning system; and obtaining a signal of a corresponding satellite currently in the sky according to pre-stored ephemeris data to implement locating. In embodiments of the present invention, ephemeris data is pre-stored before a terminal device starts GPS, so that after the terminal device starts GPS, corresponding satellites may be quickly determined according to the stored ephemeris data to implement quick locating, thereby effectively improving locating efficiency.

Abstract: A known ground location (KGL) satellite transceiver can include a position and elevation acquisition module configured to determine a time of flight (TOF) of a pseudonoise (PN) signal and a Doppler shift in a KGL signal for use in determining an orbit of a satellite. The PN signal can include a transmitted PN signal and a transponded PN signal. The KGL signal can include a transmitted KGL signal and a transponded KGL signal. The transmitted PN signal and the transmitted KGL signal can be transmitted sequentially on a first frequency carrier from the KGL satellite transceiver to the satellite. The transponded PN signal and the transponded KGL signal can be retransmitted back sequentially on a second frequency carrier from the satellite to the KGL satellite transceiver. The first frequency carrier and the second frequency carrier use a same frequency carrier or a different frequency carrier from each other.

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: 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: An improved extended ephemeris navigation receiver includes a fully autonomous satellite navigation receiver for receiving microwave transmissions from orbiting navigation system satellites, and able to demodulate navigation messages that include the ephemerides for those navigation system satellites. The improvements include a force model of the accelerations acting on a particular satellite vehicle, and are exclusive to the receiver. A single observation of the ephemeris for each SV is input and propagated days into the future by integrating each SV's orbital position with its corresponding force model. The fully autonomous satellite navigation receiver thereafter has available to it extended ephemeris predictions that can be used as substitutes when said navigation messages from the respective SV cannot otherwise be immediately obtained and demodulated.