Abstract: A multi-antenna GNSS system and method provide earth-referenced GNSS heading and position solutions. The system and method compensate for partial blocking of the antennas by using a known attitude or orientation of the structure, which can be determined by an orientation device or with GNSS measurements. Multiple receiver units can optionally be provided and can share a common clock signal for processing multiple GNSS signals in unison. The system can optionally be installed on fixed or slow-moving structures, such as dams and marine vessels, and on mobile structures such as terrestrial vehicles and aircraft.

Abstract: A rover processor determines position of a rover based upon the interaction between multiple antennas located at the rover and multiple antennas located at a base. The rover antennas may include a rover master antenna having a phase center located at the centroid of the antennas patterns of at least two auxiliary rover antennas. The rover processor may determine the position of the rover master antenna based upon the relative positions of at least two rover antennas (e.g., the rover master antenna and at least one rover auxiliary antenna, or at least two rover auxiliary antennas) with respect to at least two antennas of a base transceiver.

Abstract: A method for resolving sub-carrier ambiguities of a total number of tracking channels of a binary offset carrier (BOC) navigation signal is provided. For a simultaneously considered subset of at least four tracking channels, a set of sub-carrier candidate ambiguities is determined based on the sub-carrier modulation. Position and receiver clock error are calculated for each possible combination of sub-carrier ambiguities. Predicted delays are calculated based on each calculated position and receiver clock error. Differences between the predicted delays and the delay candidates originating from each specific combination of subcarrier ambiguities are calculated. A residual is calculated based on the differences and the set of sub-carrier ambiguities and the corresponding position and receiver clock error leading to the smallest residual are selected.

Abstract: A method for processing a set of navigation signals of a global navigation satellite system with at least three carrier signals is disclosed in which the processing of the navigation signals is based on a linear combination of the carrier signals to a combined signal. The weighting coefficients are selected such that the combined phase signal is free from geometry and free from frequency-independent disturbance variables.

Abstract: Methods and apparatus are provided for processing a set of GNSS signal data derived from signals of a first set of satellites having at least three carriers and signals of a second set of satellites having two carriers. A geometry filter uses a geometry filter combination to obtain an array of geometry-filter ambiguity estimates for the geometry filter combination and associated statistical information. Ionosphere filters use a two-frequency ionospheric combination to obtain an array of ionosphere-filter ambiguity estimates for the two-frequency ionospheric combinations and associated statistical information. Each two-frequency ionospheric combination comprises a geometry-free two-frequency ionospheric residual carrier-phase combination of observations of a first frequency and observations of a second frequency.

Abstract: A system and method for determining the heading angle of a vehicle includes first and second antennas associated with the vehicle. The first and second antennas are configured to receive signals comprising global positioning system data. A receiver front end is configured to receive the signals comprising global positioning system data. An electronic data processor is capable of receiving the global positioning system data from the receiver front end. The data processor is configured or programmed to execute a method to determine the attitude of the vehicle which may include the heading angle of the vehicle.

Abstract: Methods and apparatus are provided for estimating parameters, i.e. ambiguities, derived from GNSS signals. Observations of a GNSS signal from each of a plurality of GNSS satellites are obtained (2120). The observations are fed to a filter having a state vector comprising a float ambiguity for each received frequency of the GNSS signals (2140). The filter estimates a float value for each float ambiguity of the state vector and co-variance values associated with the state vector. Integer values are assigned to at least a subgroup of the estimated float values to define a plurality of integer ambiguity candidate sets (2160). A weighted average of the candidate sets is formed (2200). A formal precision value based on covariance values of the filter is determined (2205), the formal precision value being a measure for an achievable precision. An achieved precision value of the weighted average is determined (2210).

Abstract: A system and method for determining the heading angle of a vehicle includes first and second antennas associated with the vehicle. The first and second antennas are configured to receive signals comprising global positioning system data. A receiver front end is configured to receive the signals comprising global positioning system data. An electronic data processor is capable of receiving the global positioning system data from the receiver front end. The data processor is configured or programmed to execute a method to determine the attitude of the vehicle which may include the heading angle of the vehicle.

Abstract: Methods and apparatus are provided for estimating parameters, i.e. ambiguities, derived from GNSS signals. Observations of GNSS signals are obtained from each of a plurality of GNSS satellites (120). The observations are fed to a filter having a state vector at least comprising a float ambiguity for each received frequency of the GNSS signals (140). The filter estimates float value for each float ambiguity of the state vector. Integer values are assigned to at least a subgroup of the estimated float values to define a plurality of integer ambiguity candidate sets (160). A first number of candidate sets is selected having a quality measure better than a first threshold, wherein the first threshold is determined based on a reference quality measure of a reference candidate set (180). A weighted average of the selected candidate sets is formed, each candidate set weighted in the weighted average based on its quality measure (200).

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: The present invention relates to a method of processing Global Positioning System (GPS) carrier phase and pseudorange information. Dual-frequency carrier phase and pseudorange measurements from GPS receivers are processed by specifying separate oscillator parameters for the carrier phase and pseudorange measurements. Carrier phase estimates of errors of the oscillator are arbitrarily biased with respect to the pseudorange estimates, and ambiguity parameters are constrained to be integer-valued. Isolating the ambiguities as integer valued parameters provides extra information that can be exploited to maximize the use of GPS and other Global Navigation Satellite Systems.

Abstract: A method is described, for use with an SPS mobile terminal receiver 102, of providing a compact assistance vector to initialize and constrain the computation of the terminal's location within a region of validity. The compact assistance vector is provided to a computing node 108 able also to obtain measurements from a mobile terminal satellite positioning system receiver within said region. For a known reference point 104 within the region, the range or ranges from the reference point to one or more satellites 101 of the satellite positioning system are obtained. The range or ranges are represented by a number or numbers of ranging code repeat intervals in a limited resolution format. The compact assistance vector is created from the representation or representations of ranging code repeat intervals and transferred to the computing node 108. The compact assistance vector can then be used to initialize a location computation for the SPS mobile terminal receiver 102.

Abstract: A method for processing radionavigation signals coming from satellites that broadcast the radionavigation signals on at least two distinct frequencies, comprises receiving the signals for each satellite, realising, for each satellite, non-differentiated measurements of code and phase (10), determining the widelane ambiguities in a coherent manner on the group of satellites (12, 13, 14) by using the widelane biases associated with the satellites, received from a reference system, and global positioning of the receiver with the help of measurements of code and phase and the coherent widelane ambiguities (16, 18). The global positioning comprises, for each satellite, the determination (16) of a pseudo distance by means of an ionosphere-free combination of the measurements of code and of the difference of the phase measurements, compensated for the widelane ambiguity, this ionosphere-free combination being optimised in terms of noise.

Abstract: A method of determining the position of a GNSS receiver antenna includes steps of acquiring input data which includes observations at the GNSS receiver antenna of signals of at least clock and position information of GNSS satellites, for each of a plurality of epochs. Float parameters of a state vector from the input data of each epoch are then estimated. The float parameters include receiver antenna position, receiver clock, and at least one ambiguity per satellite. A jump in the at least one ambiguity of at least one satellite from one epoch to another epoch is detected. Then bridge parameters from the input data of at least one epoch and from the estimated float parameters are estimated. The bridge parameters include values sufficient to update the float parameters to compensate for the jump, and the bridge parameters are then used to update the float parameters.

Abstract: A method of determining coordinates of a mobile Global Navigation Satellite System (GNSS) receiver includes processing signals from space vehicles including performing measurements of pseudoranges and Doppler shift, extracting ephemeris data, and determining GNSS receiver coordinates from said measurements.

Abstract: Methods and apparatus for processing of data from GNSS receivers are presented. (1) A real-time GNSS rover-engine, a long distance multi baseline averaging (MBA) method, and a stochastic post-processed accuracy predictor are described. (2) The real-time GNSS rover-engine provides high accuracy position determination (decimeter-level) with short occupation time (2 Minutes) for GIS applications. The long distance multi baseline averaging (MBA) method improves differential-correction accuracy by averaging the position results from several different baselines. This technique provides a higher accuracy than any single baseline solution. It was found, that for long baselines (more than about 250 km), the usage of non-iono-free observables (e.g. L1-only or wide-lane) leads to a higher accuracy with MBA compared to the commonly used iono-free (LC) combination, because of the less noisy observables and the cancellation of the residual ionospheric errors.

Abstract: Methods and apparatus are provided for estimating parameters, i.e. ambiguities, derived from GNSS signals. Observations of each of received frequencies of a GNSS signal from a plurality of GNSS satellites are obtained for a plurality of instances in time (3120). The time sequence of observations is fed to a filter to estimate a state vector comprising float ambiguities, wherein each float ambiguity constitutes a non integer estimate of an integer number of wavelengths for a received frequency of a GNSS signal between a receiver of the GNSS signal and the GNSS satellite from which it is received and wherein the float ambiguities of the state vector are updated over time on the basis of the observations (3140). The occurrence of an interruption in tracking of at least one signal of a satellite is determined (3121). The float ambiguity of the state vector for the at least one signal for which an interruption in tracking occurred is maintained at the value before the interruption in tracking occurred (3122).

Abstract: A wireless communication device uses a time-invariant delay-Doppler channel response estimate for received signal demodulation. The device provides coherent signal demodulation by accounting for frequency and time selectivity in a land-based mobile communication environment, which arise mainly because of delay and Doppler shifts, respectively. In one embodiment, the wireless communication device includes a channel estimator that estimates channel response in a wireless communication network by estimating a delay-Doppler response of a wireless communication channel to obtain a delay-Doppler channel response estimate and converting the delay-Doppler channel response estimate to a time-varying channel response estimate, e.g., a time-varying frequency or impulse response. The delay-Doppler response may be estimated in a continuous or discrete domain.

Abstract: Methods and apparatus are provided for estimating parameters, i.e. ambiguities, derived from GNSS signals. Observations of GNSS signals are obtained from each of a plurality of GNSS satellites (1120). The observations are fed to a filter having a state vector at least comprising a float ambiguity for each received frequency of the GNSS signals (1140). The filter estimates a float value for each float ambiguity of the state vector. Integer values are assigned to at least a subgroup of the estimated float values to define a plurality of integer ambiguity candidate sets (1160). A quality measure is determined for each of the candidate sets. The best quality measure of the candidate sets is determined. An expectation value of the candidate set having the best quality measure is determined (1 170). An error measure as a ratio of the best quality measure to the expectation value is determined. The quality measures of the candidate sets is adapted as a function of the error measure (1180).

Abstract: A new method for bias estimation on multiple frequencies with a Kalman filter is proposed. It consists of four steps: First, a least-squares estimation of ranges, ionospheric delays, ambiguities, receiver phase biases and satellite phase biases is performed. The code biases are absorbed in the ranges and ionospheric delays, and a subset of ambiguities is mapped to the phase biases to remove linear dependencies between the unknown parameters. In a second step, the accuracy of the bias estimates is efficiently improved by a Kalman filter. The real-valued a posteriori ambiguity estimates are decorrelated by an integer ambiguity transformation to reduce the time of ambiguity resolution. Once the float ambiguities have sufficiently converged, they are fixed sequentially in a third step. Finally, a second Kalman filter is used to separate the receiver and satellite code biases and the tropospheric delays from the ranges.

Abstract: Methods and apparatus are provided for estimating parameters, i.e. ambiguities, derived from GNSS signals. Observations of a GNSS signal from each of a plurality of GNSS satellites are obtained (4120). The observations are fed to a filter having a state vector at least comprising a float ambiguity for each received frequency of the GNSS signals, each float ambiguity constituting a real number estimate associated with an integer number of wavelengths of the GNSS signal between a receiver of the GNSS signal and the GNSS satellite from which it is received, and the filter being for estimating a float value for each float ambiguity of the state vector (4140). A subset of float ambiguities of the state vector is selected (4150). Integer values are assigned to the estimated float values of the float ambiguities of the subset to define a plurality of integer ambiguity candidate sets (4160). A quality measure is determined for each of the candidate sets. A weighted average of the candidate sets is formed (4200).

Abstract: A method for performing integer ambiguity resolution in a global navigation satellite system is disclosed. A set of ambiguities, which are associated with carrier phase measurements of at least some of the signals received from the satellites in an identified set of satellites, are identified. Integer ambiguities are estimated and a best candidate set and a second best candidate set of integer ambiguity values are determined. Upon determining that the best set of integer ambiguity values fail to meet a discrimination test, each ambiguity for which integer ambiguity values in the best candidate set and second best candidate set fail to meet predefined criteria are removed from the set of ambiguities to produce a reduced set of ambiguities. The integer ambiguities in the reduced set of ambiguities are then resolved and an output is generated in accordance with the resolved integer ambiguities.

Abstract: A method for estimating satellite-satellite single difference biases is described. The method uses an ionosphere-free mixed code-carrier combination of maximum ambiguities discrimination defined at the ration between wavelength and noise standard deviation. The accuracy of the biases estimation is further improved by an additional ionosphere-free mixed code-carrier combination of time-difference measurement that is uncorrelated with the first combination. Finally, an alternative method is based on a combination of carrier signals in a common frequency band which allows estimating the biases individually.

Abstract: A global navigation system includes a first navigation receiver located in a rover and a second navigation receiver located in a base station. Single differences of measurements of satellite signals received at the two receivers are calculated and compared to single differences derived from an observation model. Anomalous measurements are detected and removed prior to performing computations for determining the output position of the rover and resolving integer ambiguities. Detection criteria are based on the residuals between the calculated and the derived single differences. For resolving integer ambiguities, computations based on Cholessky information Kalman filters and Householder transformations are advantageously applied. Changes in the state of the satellite constellation from one epoch to another are included in the computations.

Abstract: A method is suggested for robust estimation of a subset of carrier phase integer ambiguities for precise ionospheric delay estimation. The advantages of this method are the precise estimation of receiver and satellite biases, an increase in the number of reliably fixable ambiguities, and an improved accuracy for the ionospheric delay estimation.

Abstract: A global positioning system includes a base GNSS receiver that determines position and carrier phase measurements for GNSS satellites in view and a rover GNSS receiver, which is a single frequency receiver that captures GNSS satellite signals transmitted in the single frequency band during a capture window from a plurality of GNSS satellites, the plurality being large enough to provide a carrier phase data set from which a solution to associated integer carrier phase ambiguities is over determined. The system determining from the captured signals, a search space associated with the satellites in view, the code phase delays and associated position uncertainty. The system resolving the integer carrier cycle ambiguities using double difference carrier phase measurements associated with signal power values that are over a predetermined threshold value.

Abstract: A method and apparatus for directly estimating depleted ionosphere delay in a GPS receiver and using the estimate for improved navigation precision in satellite based augmentation systems.

Abstract: Methods and apparatus which characterize the ionospheric error across a network of GNSS reference stations are presented. The method relies on dual-frequency phase measurements in a geometry-free linear combination. The data are filtered for ambiguities and the characteristic parameters of the ionosphere. In combination with filter results from other combinations of phase measurements (ionosphere free combination), the physically-based model provides rapid and reliable ambiguity resolution.

Abstract: The present invention relates to a multiple carrier smoothing method for navigation satellite signals, in particular a three carrier smoothing method for Galileo signals. It provides a smoothed code solution, which is ionosphere-free to the first order and whose noise is reduced to sub-decimeter level. The method involves integer ambiguities, which can be resolved reliably. The sensitivity of the new method to receiver biases and ionospheric delays of the second order is small. The performance of the three carrier smoothing method allows to reduce the averaging interval to ?-th of its current standard value. The results refer to pseudo ranges and are geometry independent.

Abstract: Described is a generalized approach for integer parameter estimation, especially in the context of Global Navigation Satellite Systems (GNSS). The problem solved is the case where a definitively correct integer solution cannot be identified for all ambiguity parameters in a reliable way. The proposed solution is to apply a linear transformation to the ambiguities (multiply with a matrix) such that the images of the first and the second candidate (or more) are identical. That way, from the first and second (and possibly more) candidates of the integer least-squares solution, a subset of ambiguity combinations is derived that can be fixed. Thus, it is no longer necessary to choose between the solutions as they coincide for the new ambiguities. The advantage of this approach is maximizing all information still available when finally deriving additional parameters such as position, clock error, atmospheric errors and/or time correlated noise.

Abstract: A method for estimating a precise position of a user device from signals from a low earth orbit (LEO) satellite includes receiving at least one carrier signal at a user device, each carrier signal being transmitted a distinct LEO satellite. The user device processes the carrier signals to obtain a first carrier phase information. The user device recalls an inertial position fix derived at an inertial reference unit. The user device derives a position of the user device based on the inertial position fix and the first carrier phase information.

Abstract: Methods and apparatus for providing high integrity probability of connect fix (PCF) in GPS navigation applications, such as precision approach and landing and airborne refueling. In an exemplary embodiment, an enlarged pull in region is used to compute protection levels. In an exemplary embodiment, geometric extra-redundancy is used to enhance PCF and PAF (probability of almost fixed). In an exemplary embodiment, geometric extra-redundancy almost fixed solutions provide superior accuracy and integrity for GPS navigation applications.