The disclosure relates to a method for satellite-based determination of a vehicle position, comprising the following steps: a) receiving GNSS satellite data; b) determining a vehicle's position with the GNSS satellite data received in step a); c) providing input variables that can have an effect on the accuracy of the vehicle position determined in step b); d) determining a positional accuracy of the vehicle position determined in step b) using an algorithm that assigns a positional accuracy to a vehicle position; and e) adapting the algorithm.

A method, apparatus and computer program product monitor the quality of correction data. In a method, first parameter(s) associated with a navigation satellite or propagation of signals transmitted by the navigation satellite are predicted based upon prior data including prior correction data associated with the navigation satellite or the propagation of signals transmitted thereby. The method derives second parameter(s) associated with the navigation satellite or the propagation of signals transmitted thereby based upon second data including second correction data associated with the navigation satellite or the propagation of signals transmitted thereby. The second data including the second correction data is more recent than the prior data including the prior correction data. The method compares the first parameter(s) to the second parameter(s) and, based on the comparing, generates or provides information regarding the quality of the correction data.

A method, apparatus and computer program product monitor the quality of correction data. In a method, first parameter(s) associated with a navigation satellite or propagation of signals transmitted by the navigation satellite are predicted based upon prior data including prior correction data associated with the navigation satellite or the propagation of signals transmitted thereby. The method derives second parameter(s) associated with the navigation satellite or the propagation of signals transmitted thereby based upon second data including second correction data associated with the navigation satellite or the propagation of signals transmitted thereby. The second data including the second correction data is more recent than the prior data including the prior correction data. The method compares the first parameter(s) to the second parameter(s) and, based on the comparing, generates or provides information regarding the quality of the correction data.

A method for determining a 3-dimensional (3D) attitude of a platform includes receiving satellite relayed information regarding an ambiguous phase single-difference measurement (φ); resolving a phase ambiguity of the ambiguous phase single-difference measurement (φ) to determine an unambiguous phase single-difference estimate (ϕ); calculating coarse direction vectors x.sub.cor and y.sub.cor based on the unambiguous phase single-difference estimate (ϕ); estimating improved direction vectors x and y based on the coarse direction vectors x.sub.cor and y.sub.cor and by imposing constraints on the improved direction vectors x and y and an angle between the improved direction vectors x and y; and calculating the 3D attitude of the platform from the improved direction vectors x and y.

A method for determining a 3-dimensional (3D) attitude of a platform includes receiving satellite relayed information regarding an ambiguous phase single-difference measurement (φ); resolving a phase ambiguity of the ambiguous phase single-difference measurement (φ) to determine an unambiguous phase single-difference estimate (ϕ); calculating coarse direction vectors x.sub.cor and y.sub.cor based on the unambiguous phase single-difference estimate (ϕ); estimating improved direction vectors x and y based on the coarse direction vectors x.sub.cor and y.sub.cor and by imposing constraints on the improved direction vectors x and y and an angle between the improved direction vectors x and y; and calculating the 3D attitude of the platform from the improved direction vectors x and y.

The determination of an integer value bias may be performed at high speed. A positioning device, may include a FLOAT solution calculating part and an integer value bias determining part. The FLOAT solution calculating part may use carrier phase differences between carrier phases obtained by a plurality of antennas of a first station and a carrier phase obtained by one or more antennas of a second station provided separately from the first station to calculate a FLOAT solution of a particular position that is a relative position with respect to the second station, without using posture information on the first station. The integer value bias determining part may determine an integer value bias of the carrier phase difference, using the FLOAT solution of the particular position and the posture information on the first station.

A system and for determining precision navigation solutions decorrelates GPS carrier-phase ambiguities derived from multiple-source GPS information via Least-squares AMBiguity Decorrelation Adjustment (LAMBDA) algorithms. The set of decorrelated floating-point ambiguities is used to compute protection levels and the probability of almost fix (PAF), or the probability that the partial almost-fix solution corresponding to the decorrelated ambiguities is within the region of correctly-fixed or low-error almost-fixed ambiguities. While the PAF remains below threshold and the protection levels remain below alert levels, the optimal navigation solution (floating-point, partial almost-fix, or fully fixed) is generated by fixing the decorrelated ambiguities are one at a time in the LAMBDA domain and replacing the appropriate carrier-phase ambiguities with the corresponding fixed ambiguities, reverting to the last solution if PAF reaches the threshold or if protection levels reach the alert levels.

A system and for determining precision navigation solutions decorrelates GPS carrier-phase ambiguities derived from multiple-source GPS information via Least-squares AMBiguity Decorrelation Adjustment (LAMBDA) algorithms. The set of decorrelated floating-point ambiguities is used to compute protection levels and the probability of almost fix (PAF), or the probability that the partial almost-fix solution corresponding to the decorrelated ambiguities is within the region of correctly-fixed or low-error almost-fixed ambiguities. While the PAF remains below threshold and the protection levels remain below alert levels, the optimal navigation solution (floating-point, partial almost-fix, or fully fixed) is generated by fixing the decorrelated ambiguities are one at a time in the LAMBDA domain and replacing the appropriate carrier-phase ambiguities with the corresponding fixed ambiguities, reverting to the last solution if PAF reaches the threshold or if protection levels reach the alert levels.

Three or more receivers installed in a UAV receive signals from a number of satellites, and generate, based on these received signals, observation data items including information items about distances from the satellites to the receivers. An information processing apparatus calculates, based on these observation data items and on position data items of the plurality of satellites, estimated reception positions at which one or more of the receivers are estimated to receive the signals from the satellites. The information processing apparatus calculates, based on these estimated reception positions and on an estimated posture of the UAV, estimated positions of a ranging apparatus in the UAV. The ranging apparatus measures a distance to a target by applying a laser beam to the target in synchronization with timings at which the receivers receives the signals from the satellites.

A method of determining three-dimensional attitude is provided. The method includes measuring a carrier phase of each satellite signal received at plurality of spaced antenna. A carrier phase difference between the measured carrier phase for each satellite signal from each satellite received at each antenna is determined. The integrity of the integer ambiguity resolution relating to the carrier phase difference is assured by applying a least-square-error solution using differential carrier phase measurements with applied integer ambiguities between at least two of the plurality of antennas and observing measurement residuals after the least-square-error solution is computed and applying an instantaneous test, an interval test and a solution separation function. Three-dimensional attitude is determined from the carrier phase differences upon completion of the integer ambiguity resolution and the assurance of integrity of the integer ambiguity resolution.