摘要:
Control systems and methods that provide a high degree of vertical measurement accuracy for a body in motion are disclosed. The systems employ an inertial sensor system for vertical measurement and a Global Navigation Satellite System that includes multipath reduction or attenuation to provide corrected vertical information for a moving body to the inertial sensor system. The combination of these systems enables the maintenance of an accurate vertical position for said body.
摘要:
Control systems and methods that provide a high degree of vertical measurement accuracy for a body in motion are disclosed. The systems employ an inertial sensor system for vertical measurement and a Global Navigation Satellite System that includes multipath reduction or attenuation to provide corrected vertical information for a moving body to the inertial sensor system. The combination of these systems enables the maintenance of an accurate vertical position for said body.
摘要:
Methods and apparatus for processing of GNSS data derived from multi-frequency code and carrier observations are presented which make available correction data for use by a rover located within the region, the correction data comprising: the ionospheric delay over the region, the tropospheric delay over the region, the phase-leveled geometric correction per satellite, and the at least one code bias per satellite. In some embodiments the correction data includes an ionospheric phase bias per satellite. Methods and apparatus for determining a precise position of a rover located within a region are presented in which a GNSS receiver is operated to obtain multi-frequency code and carrier observations and correction data, to create rover corrections from the correction data, and to determine a precise rover position using the rover observations and the rover corrections. The correction data comprises at least one code bias per satellite, a fixed-nature MW bias per satellite and/or values from which a fixed-nature MW bias per satellite is derivable, and an ionospheric delay per satellite for each of multiple regional network stations and/or non-ionospheric corrections. Methods and apparatus for encoding and decoding the correction messages containing correction data are also presented, in which network messages include network elements related to substantially all stations of the network and cluster messages include cluster elements related to subsets of the network.
摘要:
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). Ambiguities of the weighted average can be used in subsequent operations to aid in determining a position of the receiver or can be used to prepare data, e.g., in a network processor that can be used to augment position information of a rover.
摘要:
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). Integer values are assigned to at least a subgroup of the estimated float values to define a plurality of integer ambiguity candidate sets (3160). A quality measure is determined for each of the candidate sets. A weighted average of the candidate sets is formed (3200). Ambiguities of the weighted average can be used in subsequent operations to aid in determining a position of the receiver or can be used to prepare data, e.g., in a network processor that can be used to augment position information of a rover.
摘要:
Methods and apparatus for processing of GNSS data derived from multi-frequency code and carrier observations are presented which make available correction data for use by a rover located within the region, the correction data comprising: the ionospheric delay over the region, the tropospheric delay over the region, the phase-leveled geometric correction per satellite, and the at least one code bias per satellite. In some embodiments the correction data includes an ionospheric phase bias per satellite. Methods and apparatus for determining a precise position of a rover located within a region are presented in which a GNSS receiver is operated to obtain multi-frequency code and carrier observations and correction data, to create rover corrections from the correction data, and to determine a precise rover position using the rover observations and the rover corrections. The correction data comprises at least one code bias per satellite, a fixed-nature MW bias per satellite and/or values from which a fixed-nature MW bias per satellite is derivable, and an ionospheric delay per satellite for each of multiple regional network stations and/or non-ionospheric corrections. Methods and apparatus for encoding and decoding the correction messages containing correction data are also presented, in which network messages include network elements related to substantially all stations of the network and cluster messages include cluster elements related to subsets of the network.
摘要:
A method and system for delivery of location-dependent time-specific corrections. In one embodiment, a first extended-lifetime correction for a first region is generated. A distribution timetable is used to determine a first time interval for transmitting the first extended-lifetime correction to the first region. The first extended-lifetime correction is then transmitted via a wireless communication network to said first region in accordance with said distribution timetable.
摘要:
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. (3) The stochastic post-processed accuracy (SPPA) predictor calculates during data collection an estimate of the accuracy likely to be achieved after post-processing. This helps to optimize productivity when collecting GNSS data for which post-processed accuracy is important. The predictor examines the quality of carrier measurements and estimates how well the post-processed float solution will converge in the time since carrier lock was obtained.
摘要:
Three new methods are presented to improve floating solutions and ambiguity resolution for multiple global satellite navigation systems (GNSS), one of which may be an FDMA-based GNSS such as GLONASS: (1) modeling of the hardware-related differential clock error between two (or more) different GNSS, (2) modeling the frequency-dependent biases present in frequency-division multiple access (FDMA) GNSS, and (3) an ambiguity resolution method called Scoreboard Partial Fixing (SPF). The methods presented are independent of the number of carrier frequencies tracked for each satellite navigation system. Their application results in quicker and more reliable ambiguity resolution. The benefits of combining observations of multiple GNSS are exploited in a very efficient way, in contrast to known algorithms which often result in degraded performance with multiple GNSS. The frequency-dependent bias method has been found effective with GNSS observations from a combination of substantially dissimilar hardware, e.g., for processing signals from GNSS receivers of different manufacturers.
摘要:
Three new methods are presented to improve floating solutions and ambiguity resolution for multiple global satellite navigation systems (GNSS), one of which may be an FDMA-based GNSS such as GLONASS: (1) modeling of the hardware-related differential clock error between two (or more) different GNSS, (2) modeling the frequency-dependent biases present in frequency-division multiple access (FDMA) GNSS, and (3) an ambiguity resolution method called Scoreboard Partial Fixing (SPF). The methods presented are independent of the number of carrier frequencies tracked for each satellite navigation system. Their application results in quicker and more reliable ambiguity resolution. The benefits of combining observations of multiple GNSS are exploited in a very efficient way, in contrast to known algorithms which often result in degraded performance with multiple GNSS. The frequency-dependent bias method has been found effective with GNSS observations from a combination of substantially dissimilar hardware, e.g., for processing signals from GNSS receivers of different manufacturers.