Multi-radio Integrated Navigation System M&S Software Design for GNSS Back-up
Junhak Lee (Chungnam National University) Heyone Kim (Chungnam National University) Dong-Hwan Hwang (Chungnam National University) Hyoungmin So (Agency for Defense Development) Sang Heon Oh (Navcours, Co., Ltd.)
When GNSS is not available or navigation performance is severely degraded caused by jamming and/or spoofing, the terrestrial radio navigation systems can be integrated. Before real-time integrated navigation systems are deployed, functional operation and performance can be checked through an M&S software. To this end, motion of the vehicle and environment based measurement generation is required to evaluate performance of the navigation system. In addition to this, regions, in which a given required navigation performance is satisfied, should be provided. Additional navigation signal sources should be placed if they are demanded.
In this paper, a M&S software design method is proposed for a multi-radio integrated navigation system to back-up GNSS. Since data exchange between functional modules is performed through a manager in the proposed method, each module can be operated independently. And when the M&S software is designed in the proposed method, programs of the navigation algorithm can be easily ported to the real-time navigation system.
An M&S software is designed for GPS, KGNSS (Korean GNSS), eLoran, Loran-c, DME, VOR, and pseudolite. The M&S software consists of navigation environment part, navigation algorithm part, coverage analysis part, and GUI part. The navigation environment part generates the measurements for navigation algorithm from vehicle motion, placement of navigation signal source, and radio signal channel environment. The navigation algorithm part outputs navigation results. The coverage analysis part determines the regions, in which a given required navigation performance is satisfied, and provides the position of additional navigation signal source. Users can set values and parameters for operation of the M&S software and check results of the integrated navigation system through the GUI part.
In order to check the validity of the proposed design method, a M&S software is implemented using the Visual C++ for 31 GPS satellites, 7 KGNSS satellites, 5 eLoran stations, 2 Loran-C stations, 17 DME stations, 18 VOR stations, and 3 pseudolites. After overall operation of the system was firstly represented in a state diagram, the operation of each part was programed. The results displayed in the GUI part show validity of the proposed S/W design method.