RF in Loop HLS Profile Test Station for Evaluation of GNSS Integrated Navigation System

Inertial navigation systems with expensive navigation grade accelerometers and gyroscopes are typically used for navigation in high reliability applications such as launch vehicles. Usage of GNSS receivers with measurements synchronized with INS provides the scope for incorporating inexpensive control grade MEMS gyroscopes for navigation without compromising in mission accuracy. However, it calls for additional test mechanisms to ensure the performance of the integrated navigation system under different performance conditions of GNSS receiver. Design of such an RF in loop HLS (Hardware in Loop Simulation) profile test station for evaluation of the performance of the integrated navigation system is explored in detail. The system has the capability to simulate GNSS RF signal corresponding to the mission trajectory in synchronization with angular rates simulated by angular motion simulator and other sensor data through simulation interfaces. Evaluation of the integrated navigation system and aiding algorithms using GNSS outputs has successfully been carried out using the test station and expected accuracy in navigation outputs are demonstrated.