A.N. Vereshchagin, Y.L. Fateev

When operating the navigation equipment consumers in urban areas, as well as in any other situations that characterize the presence of other reflecting objects, the input of the receiver, except for the navigation satellite signals, received multipath signals from local objects. The experimental results show that at a given point of space overall picture of multipath is mainly a stationary character, in the sense that the error in multipath repeats on the next flight of the satellite. This allows you to create a model for the multipath stationary object. Highly accurate navigation measurements at a fixed point can occur for base stations differential correction radio navigation field monitoring stations, as well as in the case without uplink measurement stations ephemeris-time support for GLONASS. Multipath error, even when taking the necessary measures (use of error-correcting antenna with partial suppression of the signals coming from low angles, choosing the location of the receiving antenna, the phase smoothing of the measured pseudorange and the narrowing of the aperture of the discriminatory features) range from 0.5 to 2 m, which greatly exceeds the requirements for accuracy pseudorange measurement. The basis of constructing a model of interference on the following assumptions: - Using equipment MRK-33 [2] in the uplink without measuring station antenna system is stationary and is located in the points with known coordinates; - The frequency of traffic routes and satellite visibility zones for ground facilities, an interval which is 17 turns. For the first 17 turns of the table is constructed based on the values of noise azimuth, elevation, and the literals turn, starting with the elevation angle of 15 °. The value of noise is estimated as the difference between code and phase of the navigation signal, after compensating the influence of the ionosphere two-frequency method. Of all the values obtained on the same circuit, subtract the value at the zenith, to eliminate the phase ambiguity. The resulting table is used to compensate for the next 17 turns, with subsequent correction of the table. Experimental studies have shown that on the basis of the model noise could offset the impact of multipath on the 2.7-fold elevation angles above 15°.