NTA supported pre-flight and post-flight navigation predictions and analysis in support of Operational Test (OT) flights of the Army Tactical Missile System (ATACMS) Modernization (AMOD). Support included modeling, simulation, test, and analysis in an effort to determine navigation performance and ensure a successful OT in a GPS-degraded environment. Modeling/simulation of the GPS/inertial navigator was conducted prior to integration of the AMOD GPS/inertial navigator into a hardware-in-the-loop (HWIL) test environment. The AMOD GPS anti-jam antenna was characterized and modeled to simulate satellite visibility and anti-jam performance. The models were successfully incorporated into a GPS Interference And Navigation Tool (GIANT) simulation prior to accurately replicating actual jammer characteristics in the HWIL. GIANT and HWIL simulations compared favorably.
The AMOD GPS/inertial navigator was mechanically/electrically integrated into AvMC’s HWIL test facility. An inertial electronics emulator was developed to provide simulated accelerometer/gyro data. The inertial data was successfully integrated (time synchronized) with the radio frequency output of a GPS satellite simulator. This HWIL test setup allowed the embedded GPS/inertial navigation software, as well as the GPS receiver hardware/software, to be exercised in an inertial/GPS simulated dynamic environment across representative trajectories. The refinement of simulation/models was required in order to gain confidence for pre-flight predictions. HWIL simulations were compared to data from actual flight tests. Final results support verification of NTA’s simulation/test capabilities for AMOD performance predictions at all supported ranges and GPS threat scenarios.