An Electrostatic Roll Sensor for Supersonic Vehicles Part I: Feasibility and Flight Tests

Abstract

A simple, rugged, and low-cost roll sensor developed for model aircraft has been adapted for use on supersonic missiles and projectiles. Pairs of ionizing elements placed symmetrically about the vehicle roll axis sense the vertical electrostatic gradient in the earth's atmosphere, which produces a voltage differential between sensors proportional to their vertical separation distance. Recessing the sensors below the supersonic freestream allows adequate ionization to occur and thus maintains sensor sensitivity. Large separation distances between individual sensors are not required to generate a sufficient voltage differential. Several missile and projectile flight tests were conducted at velocities up to Mach 2.1, roll rates between 2-13 Hz, and altitudes ranging from sea level to 3000 ft. Under these test conditions, sensor accuracy was generally within ±5 deg of true roll position.