Design and Testing of a High Performance Relative Inertial Navigation System

摘要

The performance of Ultra-Tightly Coupled (UTC) Global Positioning System/Inertial Navigation System (GPS/INS) systems and precision Electronic Support Measures (ESM) emitter location systems in military aerospace vehicles are compromised by the flexure and vibration between the various antenna locations and the aircraft’s Inertial Navigation System (INS). Conventional approaches attempt to estimate the antenna’s navigation state using the aircraft’s INS data and nominal rigid body antenna lever arm with respect to the aircraft’s INS. Because of flexure and vibration, the conventional approach significantly compromises the performance of UTC GPS and ESM systems. This paper presents a different approach to significantly improve the performance of these systems by locating a small, lowcost remote inertial measurement unit (IMU) at or near the antenna’s phase center. The remote IMU measurements are used to compute the relative position, velocity, and attitude of the antenna with respect to the master GPS/INS. Then the IMU measurements in combination with the aircraft’s INS data are used by the UTC GPS/INS or ESM algorithms to correct for the dynamic flexure motion of the antenna and improve system performance. Honeywell, on the Antenna Advanced Inertial Reference for Enhanced Sensors (ANTARES) program from the Air Force Research Laboratory, has implemented an algorithm to compute a high precision relative navigation solution between a navigation grade master INS and a tactical grade remote IMU. A test apparatus was designed and constructed to simulate wing and fuselage flexure motion. The test apparatus was used to test the ANTARES system under several different conditions. This paper describes the relative navigation solution approach and presents results that characterize its performance in these tests.