METHOD OF AUTOMATIC TRANSMISSION OF THE INTEGRITY BREACH SIGNALS OF THE RIVER LOCAL DIFFERENTIAL SUBSYSTEM

The integrity of the navigation system is one of the important factors affecting the safety of navigation. Currently, on the inland waterways of Russia, alerts on the integrity of the GLONASS global navigation satellite system (GNSS) are transmitted through river local differential subsystems (LDSS), which include one or more reference stations. Industrial interference from industrial zones and power lines, mutual interference from neighboring reference stations and, especially, the inhomogeneity of the underlying surface affect the range of the reference stations, which leads to the integrity breach of the differential field and transmission of unreliable corrective information to the navigator. However, the navigator is not notified of the incorrect operation of the reference stations. As a result, inaccurate corrective information leads to errors in calculating the vessel position, which reduces the level of navigation safety. A method for the automatic transmission of notifications about the LDSS integrity breach from a remote control and management station (RCMS) to the ship is presented in the paper. The structure of the message transmitting the notification signal has been formed. Criteria characterizing the quality of the differential correction signal are presented. Possible combinations of such criteria, which determine the performance of the differential mode of the reference station, are identified. Each combination of criteria is juxtaposed the corresponding notification texts displayed on the monitors of the LDSS operators and on the navigator’s display. A scheme for the automatic transmission of an alarm message from a remote control point through the RCMS, the regional command and control center, the vessel traffic control center and base stations of the automatic identification system (AIS) to ship transponders has been developed. As a result, the developed method for transmitting the alarm message containing combinations of quality criteria for the differential correction signal allows to automatically inform the navigator about the reliability of the corrective information transmitted by one or another reference station.