Abstract: A method comprises generating a respective code-carrier difference for each of a plurality of satellite vehicle and signal frequency combinations, wherein the code-carrier difference is based on a code range and a carrier range. The method also comprises filtering the respective code-carrier difference for an unknown bias and random noise; determining whether multipath is present for each of the plurality of satellite vehicle and signal frequency combinations based on the respective filtered code-carrier difference; and computing a position solution based on trust placed in respective measurements from each of the plurality of satellite vehicle and signal frequency combinations, the trust based on whether multipath is present for the respective satellite vehicle and signal frequency combination.

Abstract: Disclosed are various embodiments of Global Navigation Satellite System (GNSS) chipsets or architecture. Based upon a requested accuracy and/or update of a host application, embodiments of the disclosure can calculate position data points on-board the GNSS chipset or allow a host processor to calculate position data points, which can allow the host processor to enter a low power mode if the requested update rate and/or accuracy allow.

Abstract: The device for receiving signals which have carrier frequencies and codes, said signals being navigation or communication signals, has multiple individual antennas (114) for receiving a signal, each individual antenna (114) having an antenna output (116) at which the received signal is present. Furthermore, the device is provided with an analog preprocessing unit (122) for preprocessing the signals received by the individual antennas (114), said preprocessing unit (122) having signal transmitting and signal preprocessing channels (124) which are assigned to the individual antennas (114), and the device is provided with a digital signal processor (134). The device additionally has a calibration signal generating unit (148) for generating a calibration signal which, like the signals received by the individual antennas (114), has a carrier frequency and a code and which is used for calibrating the propagation time and the phase of the signal transmission paths.

Abstract: A signal processing method of a positioning apparatus includes the following steps. A satellite signal is received to provide at least a distance information. A correction value of a phase measurement time is generated according to the distance information and phase data of the satellite signal are corrected in sequence accordingly. The phase data are received and when a quantity of the phase data is equal to a preset quantity, a first low order polynomial fitting and a first Chi-square test are performed to generate an estimated parameter. A next phase data of the satellite signal is estimated to generate an estimated phase data according to the estimation parameter. An actual phase data is obtained. A detection and a compensation of a cycle slip are performed according the estimated phase data and the actual phase data to output a corrected phase observation value.

Abstract: A self-surveying range includes a base station and a plurality of nodes. Each node has a transmitter, a receiver and a processor and is capable of transmitting a signal encoded with a node identifier, the transmission time. The node can also receive transmitted signals from other nodes. The base station also has a transmitter, a receiver and a processor. The base station is capable of determining its location, transmitting an encoded signal with the transmission time and receiving transmitted signals from said plurality of nodes at a definite time. The base station processor can determine the location of each node from the base station location, the node transmission time and the definite reception time. There is further provided a method for establishing a self-surveying range.

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 civil engineering machine has a machine control unit configured to determine data which defines the position and/or orientation of a reference point on the civil engineering machine in relation to a reference system independent of the position and orientation of the civil engineering machine. A geometrical shape to be produced on the ground is preset in either a machine control unit or a field rover control unit. The field rover is used to determine a position of at least one identifiable point of the preset geometrical shape in the independent reference system. Curve data defining a desired curve in the independent reference system, corresponding to the preset shape, is determined at least partially on the basis of the position of the at least one identifiable point of the preset geometrical shape in the independent reference system.

Abstract: A route search device includes: map data; a derived route acquisition section that acquires a first derived route from an origin point to a destination; a route correction region acquisition section that acquires a route correction region; a place to be passed through setting section that sets a place to be passed through in the route correction region; a start point and end point setting section that sets a start point and an end point in the route correction region; a corrected route acquisition section that acquires a corrected route; and a route correction section that corrects the first derived route to a second derived route from the origin point to the destination, constituted by a route from the origin point to the start point, the corrected route, and a route from the end point to the destination.

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 system and methods for resolving integer cycle ambiguity in medium wave carrier radio signals are presented. A satellite signal is received at a receiving location and a measured code phase of the satellite signal is measured. A satellite location estimate of the receiving location is computed based on the measured code phase. Medium wave radio carrier signals from medium wave radio transmitters are received at the receiving location. A number of wavelengths of the medium wave radio carrier signals from the satellite location estimate to each of the medium wave radio transmitters is determined respectively. A carrier phase of each of the medium wave radio carrier signals is measured. An improved position estimate of the receiving location is computed based on the number of wavelengths and the carrier phase of each of the medium wave radio carrier signals, and a location of each of the medium wave radio transmitters.

Abstract: A primary phase measurement device measures a first carrier phase and a second carrier phase of carrier signals received by the location-determining receiver. A secondary phase measurement device measures the third carrier phase and the fourth carrier phase of other carrier signals. A real time kinematic engine estimates a first integer ambiguity set associated with the measured first carrier phase and a second integer ambiguity set associated with the measured second carrier phase. The real time kinematic engine estimates a third ambiguity set associated with the measured third carrier phase and a fourth ambiguity set associated with the measured fourth carrier phase. A compensator is capable of compensating for the inter-channel bias in at least one of the third ambiguity set and the fourth ambiguity set by modeling a predictive filter in accordance with various inputs or states of the filter estimated by an estimator.

Abstract: A method and system for estimating the position comprises measuring a first carrier phase of a first carrier signal and a second carrier phase of a second carrier signal received by a location-determining receiver. A primary real time kinematic (RTK) engine or receiver data processing system estimates a primary integer ambiguity set associated with at least one of the measured first carrier phase and the measured second carder phase. A quality evaluator determines if a primary integer ambiguity set is resolved correctly to the predefined reliability rate during an earlier evaluation period. A secondary real time kinematic (RTK) engine or receiver data processing system estimates a secondary integer ambiguity set associated with at least one of the measured first carrier phase and the measured second carrier phase during a later period following the earlier evaluation period.

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 Cholesky 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: 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 filter estimates a float value for each float ambiguity of a state vector determined from GNSS signals. Integer values are assigned to at least a subgroup of the estimated float values to define integer ambiguity candidate sets. A quality measure is determined for each of the candidate sets. An expectation value of the candidate set having the best quality measure is determined. 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. A weighted average of a subgroup of the candidate sets on the basis of the adapted quality measures is formed. Ambiguities of the weighted average can be used in subsequent operations to aid in determining a position of the receiver.

Abstract: For supporting a change of a reference station, first data that is valid for a first reference station is provided for transmission to a device, then data that is valid for the first reference station and data that is valid for a second reference station is provided for transmission to the device in parallel for a limited time, and finally data that is valid for the second reference station is provided for transmission to the device. The data for the first reference station and the data for the second reference station include measurements on satellite signals. At a receiving end, the respectively received data can be provided for a positioning of a device comprising a satellite signal receiver.

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: Method to estimate parameters derived at least from GNSS signals useful to determine a position, including obtaining at least one GNSS signal observed at a GNSS receiver from each of a plurality of GNSS satellites; receiving global correction information useful to correct at least the obtained GNSS signals from a first set of GNSS satellites, wherein the global correction information includes correction information which is independent from the position to be determined; receiving local correction information useful to correct at least the obtained GNSS signals from a second set of GNSS satellites, wherein the local correction information includes correction information which is dependent on the position to be determined; processing the obtained GNSS signals from the first set of GNSS satellites by using the global correction information; and processing the obtained GNSS signals from the second set of GNSS satellites by using the local correction information.

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: A low-latency centralized RTK system utilizes an RTK server to perform matched updates using base station GNSS measurements from one or more base stations and GNSS measurements from one or more rovers, and the one or more rovers produce RTK solutions based on the results of the matched updates. The RTK server includes one or more processors that perform the matched updates and a transmitter that transmits at least the ambiguities to the rovers. The respective rovers, which have processing power that is sufficient to quickly calculate RTK baselines, utilize the received ambiguities, the base station GNSS measurements received from either the RTK server or the base stations, known base station positions and instantaneous GNSS measurements at the rovers to readily determine and update their RTK baselines and their precise positions.

Abstract: Methods and apparatus provide for positioning of a rover antenna from GNSS data derived from multi-frequency signals and correction data derived from a network of reference stations. Rover antenna position and multi-frequency ambiguities are estimated at each epoch. An ionospheric filter models variation in ionospheric bias per satellite. A set of ionospheric carrier-phase ambiguities is estimated at least when the multi-frequency ambiguities have attained a predetermined precision. The estimated ionospheric carrier-phase ambiguities are cached. After detecting interruption of signal at the rover antenna and determining reacquisition of signals at the rover antenna, an ionospheric bias per satellite over an interruption interval is predicted. For each satellite, a cached ionospheric carrier-phase ambiguity is combined with a predicted ionospheric bias to obtain a post-interruption ionospheric ambiguity estimate.

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: Methods and apparatus for determining a precise position of a rover located within a region are presented using rover observations comprising code observations and carrier-phase observations of GNSS signals on at least two carrier frequencies over multiple epochs. Correction data is received for each of the epochs at least one code bias per satellite. Synthetic reference data is generated for each of the epochs from the correction data for a synthetic station location. A determination is made for each epoch whether a cycle slip has occurred. Upon determining that a cycle slip has occurred, values of any variables of a set of state variables which are affected by the cycle slip are reset. Each epoch of rover observations and correction data is used to estimate updated values for the set of state variables including a set of ambiguities and coordinates of a precise rover position.

Abstract: Methods and apparatus provide for positioning of a rover antenna from GNSS data derived from multi-frequency signals and correction data derived from a network of reference stations. At each of a plurality of epochs, the GNSS data and correction data are used to estimate values defining a rover antenna position and a set of multi-frequency ambiguities. An ionospheric-free carrier-phase ambiguity per satellite is estimated based on a known rover antenna position. The estimated ionospheric-free carrier-phase ambiguity is combined with an estimated widelane ambiguity and with an estimated ionospheric-free ambiguity and with values defining the known rover antenna position to obtain values defining an aided rover antenna position and aided multi-frequency ambiguities.

Abstract: In a position measuring method, GPS ranging data obtained at a reference station 1 and an observation station 2 is inputted to four solution calculating sections 12, RTK solutions such as a fix solution at the observation station 2 are calculated in the solution calculating sections 12 according to the RTK system, and the RTK solutions are inputted to a solution obtaining unit 13. Further, it is decided whether or not the RTK solutions include multiple fix solutions. When it is decided that the RTK solutions include multiple fix solutions, deviations between the fix solutions are determined and it is decided whether or not the deviations exceed an allowable value. When it is decided that none of the deviations exceed the allowable value, predetermined arithmetic processing is performed on the fix solutions to obtain a normal fix solution. Moreover, the solution calculating sections are sequentially restarted at predetermined time intervals.

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: 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 method and system for estimating the position comprises measuring a first carrier phase of a first carrier signal and a second carrier phase of a second carrier signal received by a location-determining receiver. A primary real time kinematic (RTK) engine or receiver data processing system estimates a primary integer ambiguity set associated with at least one of the measured first carrier phase and the measured second carder phase. A quality evaluator determines if a primary integer ambiguity set is resolved correctly to the predefined reliability rate during an earlier evaluation period. A secondary real time kinematic (RTK) engine or receiver data processing system estimates a secondary integer ambiguity set associated with at least one of the measured first carrier phase and the measured second carrier phase during a later period following the earlier evaluation period.

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 carrier phase correction sub-system for use with a GNSS receiver that utilizes an active null and beam steering controlled radiation pattern antenna (CRPA) determines carrier phase corrections that compensate for antenna phase center movements in the carrier phase measurements taken from the CRPA filtered signal. The carrier phase sub-system utilizes measured radiation patterns, angles of incidence of the satellite signals at the CRPA, and the applied weights to determine carrier phase corrections to be applied to the CRPA filtered signals from which the carrier phase measurements are later taken or to the carrier phase measurements depending on the dynamics of the jamming signal. With the carrier phase corrected, the GNSS receiver may utilize known RTK techniques to resolve carrier cycle ambiguities.

Abstract: A method and system for identification of ship state tonal parameters during an approach and landing of an aircraft on a ship is provided. The method comprises determining whether ship state data is available to the aircraft prior to landing of the aircraft, and when the ship state data is available to the aircraft, receiving the ship state data at the aircraft and estimating tonal parameters of the ship state data. When the ship state data is not available to the aircraft, a determination is made whether a ship tonal parameter estimation is complete. When the ship tonal parameter estimation is complete, ship state data is estimated using any last received ship state data and estimates of the ship tonal parameters. One or more relative navigation algorithms are then run using the received ship state data or the estimated ship state data to safely land the aircraft on the ship.

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: An equation derivation section derives an observation equation that employs M epochs worth of GPS data and INS data as observation values to derive for each of the GPS satellites a float solution for number of waves of GPS data carrier wave between each of plural GPS satellites and a vehicle, wherein the range of float solutions of the number of waves is constrained by the vehicle travel path estimated based on M epochs worth of INS data. The observation equation is solved by a float solution computation section and float solutions computed for the number of waves N and the position of the vehicle for each of the GPS satellites. Fixed solutions with highest consistency are computed by a fixed solution computation section based on the float solutions for the number of waves N for each of the GPS satellites and the position of the vehicle.

Abstract: A primary phase measurement device measures a first carrier phase of a first carrier signal and a second carrier phase of a second carrier signal received by the location-determining receiver. A secondary phase measurement device measures the third carrier phase of a third carrier signal and the fourth carrier phase of fourth carrier signal. A real time kinematic engine estimates a first integer ambiguity set associated with the measured first carrier phase, and a second integer ambiguity set associated with the measured second carrier phase. The real time kinematic engine estimates a third ambiguity set associated with the measured third carrier phase and a fourth ambiguity set associated with the measured fourth carrier phase. A compensator is capable of compensating for the inter-channel bias in at least one of the third ambiguity set and the fourth ambiguity set by modeling a predictive filter (e.g.

Abstract: A method and system for estimating the position comprises measuring a first carrier phase of a first carrier signal and a second carrier phase of a second carrier signal received by a location-determining receiver. A primary real time kinematic (RTK) engine or receiver data processing system estimates a primary integer ambiguity set associated with at least one of the measured first carrier phase and the measured second carrier phase. A quality evaluator determines if a primary integer ambiguity set is resolved correctly to the predefined reliability rate during an earlier evaluation period. A secondary real time kinematic (RTK) engine or receiver data processing system estimates a secondary integer ambiguity set associated with at least one of the measured first carrier phase and the measured second carrier phase during a later period following the earlier evaluation period.

Abstract: An inter-moving body interferometric positioning system for carrying out positioning in coordination with three or more moving bodies that can mutually communicate, including: a reference vehicle decision unit for deciding on a single moving body to function as a reference vehicle from among three or more moving bodies, and a positioning unit for interferometrically determining respective relative positions of other moving bodies relative to the reference moving body that is to function as a reference vehicle decided on by the reference moving body decision unit using satellite wave monitoring data monitored in each of the three or more moving bodies. This inter-moving body interferometric positioning system specifies relative positions among the other moving bodies using positioning results of the positioning unit.

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: Methods and apparatus are presented for determining a position of an antenna of a GNSS rover from observations of GNSS signals collected at the antenna over multiple epochs and from correction data for at least one of the epochs. A first-epoch rover position relative to a moving base location is determined, a second-epoch update of the first-epoch rover position relative to the moving base location for a second epoch is determined using a single-differenced delta phase process, and the first-epoch position and the second-epoch update are combined to obtain a second-epoch rover position relative to a moving base location of the second epoch.

Abstract: A method and system to handle single failure GPS faults in high integrity relative positioning systems is provided. The system is configured to receive a number of reference measurements in carrier-phase real time kinetic positioning systems and identify if a single fault exists. The system identifies the type of fault and mitigates the effects of the single fault to provide a positioning system with a high integrity that is suitable for applications involving risk to human lives.

Abstract: Some embodiments of the present invention derive an ionospheric phase bias and an ionospheric differential code bias (DCB) using an absolute ionosphere model, which can be estimated from data obtained from a network of reference stations or obtained from an external source such as WAAS, GAIM, IONEX or other. Fully synthetic reference station data is generated using the ionospheric phase bias and/or the differential code bias together with the phase leveled clock and ionospheric-free code bias and/or MW bias.

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: 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 method of detecting a plasma depletion in the ionosphere includes comparing the large scale ionosphere trend with a local temporal slope of vertical or slant delay. In one example, the local temporal slope of delay is calculated phase data extracted from GPS signals at a GPS receiver, and the large scale trend is determined from broadcast ionosphere grid point delay data.

Abstract: According to a preferred aspect of the instant invention, there is provided a system and method for using satellite communications satellites to control and receive data from a land cableless seismic system. The satellite transmission could transmit control signals (e.g. turn on/off) and receive signals from the remote seismograph units (seismic data, quality control parameters, status, location, etc.) which would subsequently be retransmitted to a processing center or other surface facility.

Abstract: A method for locating GNSS-defined points, distances, directional attitudes and closed geometric shapes includes the steps of providing a base with a base GNSS antenna and providing a rover with a rover GNSS antenna and receiver. The receiver is connected to the rover GNSS antenna and is connected to the base GNSS antenna by an RF cable. The receiver thereby simultaneously processes signals received at the antennas. The method includes determining a vector directional arrow from the differential positions of the antennas and calculating a distance between the antennas, which can be sequentially chained together for determining a cumulative distance in a “digital tape measure” mode of operation. A localized RTK surveying method uses the rover antenna for determining relative or absolute point locations. A system includes a base with an antenna, a rover with an antenna and a receiver, with the receiver being connected to the antennas.

Abstract: Methods and apparatus are presented for determining a position of an antenna of a GNSS rover from observations of GNSS signals collected at the antenna over multiple epochs and from correction data for at least one of the epochs. A first-epoch rover position relative to a base location is determined for a first epoch using a single-differencing process based on one of (i) fixed carrier-phase ambiguities and (ii) a weighted average of carrier-phase ambiguity candidates which is converged to a predetermined threshold. A second-epoch rover position relative to a base location is determined for a second epoch using a single-differencing process. A second-epoch update of the first-epoch rover position relative to the base location is determined for the second epoch using a single-differenced delta phase process and the first-epoch rover position is combined with the second-epoch update to obtain a second-epoch delta phase rover position relative to a moving base location of the second epoch.

Abstract: A linear least squares (LLS) estimator provides a low complexity estimation of the location of a mobile terminal (MT), using one of the fixed terminals (FTs) as a reference FT to derive a linear model. A method for selecting a reference FT is disclosed, which improves the location accuracy relative to an arbitrary approach to selecting the reference FT. In addition, a covariance-matrix based LLS estimator is proposed in line-of-sight (LOS) and non-LOS (NLOS) environments to further provide accuracy, taking advantage of the correlation of the observations. Different techniques for selecting the reference FT under non-LOS (NLOS) conditions are disclosed. A map-based two-stage LLS estimator assists in selecting the reference FT under NLOS conditions.

Abstract: Methods and apparatus are described for processing a set of GNSS signal data derived from signals of a set of satellites having carriers observed at a rover antenna, wherein the data includes a carrier observation and a code observation of each carrier of each satellite, comprising: obtaining for each satellite clock corrections comprising at least two of: (i) a code-leveled satellite clock, (ii) a phase-leveled satellite clock, and (iii) a satellite clock bias representing a difference between a code-leveled satellite clock and a phase-leveled satellite clock, running a first filter which uses at least the GNSS signal data and the satellite clock corrections to estimate values for parameters comprising at least one carrier ambiguity for each satellite, and a covariance matrix of the carrier ambiguities, determining from each carrier ambiguity an integer-nature carrier ambiguity comprising one of: an integer value, and a combination of integer candidates, inserting the integer-nature carrier ambiguities as ps

Abstract: The present invention relates to a method for computing autonomous horizontal and vertical Protection Levels for least squares-based GNSS positioning, based on navigation residuals and an isotropic confidence ratio.