METHOD OF LOCAL DETERMINATION OF MOBILE AND FIXED OBJECTS WITH SIGNALS OF GLOBAL NAVIGATION SATELLITE SYSTEMS Russian patent published in 2017 - IPC G01C21/00 G04G17/00 

FIELD: radio engineering, communication.

SUBSTANCE: method is implemented by taking into account signals from the direct and indirect lines of sight. It is based on the method of mapping to the map. In this case, the method is based on the configuration of visible and invisible satellites for possible candidate solutions taking into account the terrain landscape, thereby increasing the accuracy of position determination. To implement the method, an algorithm is proposed that consists of an autonomous and an active stage. In the autonomous phase, the boundaries of buildings are formed on the grid of locations. The boundaries of buildings are constructed from the perspective of the GNSS user position, the edge of the building is defined for each azimuth (from 0 to 360°) in the form of a series of angles. The result of this stage shows where the edges of buildings are located within the celestial grid. Once a boundary is defined relative to the celestial grid, it can be stored and easily reused in the online phase to predict the satellite's visibility by simply comparing the height of the satellite with the height of the building in the same azimuth. At the second step of the active phase of the solution search, the area in which probable location solutions are located in the shaded area is determined. The search area is determined based on the initial position generated at the first step of determining the coordinates on the LOS (line of sight) Satellites. The simplest implementation is a fixed circle with the center at a known coordinate, however, more advanced positioning algorithms can also be used here. The third step compares the height of the satellite with the probable position with the height of the boundary of the buildings in the same azimuth. At the fourth step, the similarity between predicted visibility and actually observed is estimated. The candidate of the position with the best coincidence will be weighted higher in the decision with the shaded task. There are two stages of calculating the evaluation for the candidate position. Firstly, the definition of the observed coal on the estimated schemes. Secondly, the evaluation function provides a position between the observed signal and its estimate, which is described by the formula:

,

where ƒ_pos(j) is the position estimate for the grid point j, ƒ_sat(i, j, SS) is the estimation of the position of satellite i in grid j using the estimated matrix SS. At the end of this stage, each position candidate must have an estimate that represents the angle that indicates the visibility of the satellite, and therefore how likely is the candidate's position to be close to solving the navigation task. After determining the configuration and estimating the visible satellites, invisible satellites are evaluated for each candidate node in the navigation task solution. The last step is to determine the situation with the help of the scores obtained by comparing the candidates with the sample.

EFFECT: improved accuracy.

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