Identification of pilot-vehicle dynamics from in-flight tracking data

The increasing cost and complexity of ground simulation and flight test make it imperative that researchers and engineers maximize the amount of useful information they can obtain from these endeavors. Although the analytical techniques for identifying pilot-vehicle dynamics in well-defined flight tasks have been available for a number of years, the routine exercise of such techniques is still something of a rarity in simulation and flight test activity. The reason for this can often be traced to the fact that the effort involved in undertaking such identification often dominates the test activity itself. A nonintrusive identification program is exercised to shed light on the ability of such programs to serve as a practical tool for simulation and flight test engineers. Data from a simple but representative flight task involving an F-14 pursuer aircraft tracking a T-38 target aircraft in a 3-£ windup turn and in level flight are used. Comparative identification results are provided by a Fourier coefficient method that requires a carefully designed and implemented input consisting of a sum of sinusoids. The least-squares results compare quite favorably with those of the Fourier technique. An example of crossover frequency regression is uncovered and discussed in light of the conditions surrounding one of the flight test configurations.