Inertially Augmented Automatic Landing System: Autopilot Performance with Imperfect ILS Beams
Final rept. 1 Jul 1971-1 Apr 1972
BOEING CO SEATTLE WA
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The report considers the capability of three autopilots, with varying dependency or inertial navigation inputs, to perform the automatic landing task in the presence of ILS beam anomalies. Three sets of pitch and roll axis control laws for a commercial jet transport were analyzed and flight tested to determine their comparative advantages and limitations. Conventional autopilots with only minor or no reliance on inertial inputs are sensitive to ILS beam imperfections. It is shown that complementary filtering of ILS position information with INS- derived acceleration and velocity results in a very marked attenuation of airplane response to beam bends, noise, and overflight interference. A set of equations is derived by which the acceptability of system performance during an automatic approach can be assessed. The capability of the three autopilots to provide acceptance on Category 1 and 2 ILS beams is investigated.
- Flight Control and Instrumentation