Comparison of Transfer Alignment Methods for Fixed-Wing Air Vehicles with Actual F-16 Flight Data

摘要

For air-launched missiles, initialization of the navigation system is highly critical, since any small error in the initial angles may lead to high position error. Transfer alignment algorithms are used to accurately initialize the navigation systems by comparing the navigation solutions of the reference system and the missile. There are various transfer alignment techniques depending on the measurements to be compared such as velocity, integrated velocity, attitude, rates etc. This paper provides the design details of the velocity matching (VM) and integrated velocity matching (IVM) techniques. Although, IVM appears to be intuitionally straightforward after the design of VM, there are some crucial key points that have to be considered. In this respect, this paper not only formulates these two transfer alignment methods in detail, but also describes the critical points in the implementation of the algorithm. Moreover, the performances of two methods are compared by using actual F-16 flight test data set, not by synthetic simulation data. Captive carry tests are operated by performing an S-maneuver. The each collected flight data is about 500 seconds. On the post-process, both algorithms are replayed until the simulated launch, which occurs at the end of the S-maneuver. The inertial navigation algorithm is initialized by the transfer alignment results at the launch. Then, at the end of the 80 second inertially guided flight, the final position error is calculated by using the platform data as reference. This position error will be focused on as the performance criterion of these two techniques.