G.W. Braun

The impact point of an intercontinental ballistic missile depends mainly upon the magnitude and angular position of the velocity vector at burnout. The required impact point accuracy is determined by the yield of the warhead and the hardness of the target. It is assumed these conditions are such that the three velocity components have to be accurate within one part in 20,000. A test of an inertial guidance system has to check if the random errors of the system are sufficiently below this error threshold and has to calibrate the system so that the systematic errors can be compensated for with the required accuracy. The sensing part of the guidance system being composed of platform and platform mounted accelerometers, the calibration consists of monitoring the platform position and comparing the integrated output of the platform mounted accelerometers with externally measured velocity. Discussion of an error model of an inertial guidance system shows that the test has to be performed in an environment which is as similar to the missile environment as possible. This type of environment is provided by a supersonic sled. The sled environment also has the advantage of accurate reproducibility. The acceleration profile of a conventional guidance sled test is shown and the location of the autocollimators measuring the platforms angular position illustrated. The external velocity measurement is based on the measurement of the time when the sled passed equidistant markers. The evaluation of these distance-time measurements needs smoothing of the test results. The smoothing method is described and a bias error of only one part in 40,000 is found. The vibration environment in the sleds payload compartment has a decisive influence on the test specimens systematic errors. The vibrations are measured and their power spectral density is calculated. The difference between internal and external velocity measurements is plotted. The results are used for deriving the coefficients of the error model.

WGL-Tagung 1961, Freiburg im Breisgau

Conference Paper

englisch

A4, 6 Seiten

Jahrbuch der Wissenschaftlichen Gesellschaft für Luftfahrt, 1961, Jahrbuch der Wissenschaftlichen Gesellschaft für Luftfahrt; S.308-313; 1962; Braunschweig : Vieweg

NA

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1962