RESEARCH OF QUALITY INDICATORS OF GNSS SIGNAL RECEIPT BY NAVIGATION EQUIPMENT OF MACHINE-TRACTOR UNITS

In the world, precision farming, which is based on geo-information technologies, has become widespread. The precision farming system application ensures a more rational use of cultivated areas and increases the ecological protection of soils. Using the ASN-Agro parallel driving system with the ASN-Agro V1.03 software, the effect of ground obstacles (forest strips, power lines) on the number of satellites, which are within the range of navigation equipment, is investigated in the article. The number of satellites, which are within the range of navigation equipment, and the number of satellites used by the navigation equipment were determined by applying the satellite filter. The quality indicator of signal received by the navigation equipment according to the SNR (signal/noise) indicator were studied. Research of SNR-signals from GNSS satellites was carried out using the GPS Test application. Signals from GPS satellites had the best value of SNR indicators. Machine-tractor units perform technological operations next to forest and power lines, which create interference («radio shadow») for GNSS-signals. The influence of «radio curtains» caused by forest and power lines on the quality of GNSS-signals received by the antenna of the navigation equipment of the machine-tractor unit was examined. The quality of GNSS-signals was evaluated based on indicators of DOP signal accuracy reduction: for location – PDOP; in the horizontal plane – HDOP; in the vertical plane – VDOP. Research on DOP indicators was carried out using the Precision GPS PRO application. The conducted studies established that the greatest impact on indicators of DOP signal accuracy reduction is caused by interference from 200 kV power lines. The highest value of DOP signal accuracy reduction indicators was recorded when the navigator's antenna was located at a distance of 5 m from the 200 kV power line. If the antenna of the navigation equipment is located at a distance of 25 m or more from the forest, it almost does not affect the indicators of the decrease in the accuracy of the DOP signal.