Flight test results of miniature, low cost, spin, accelerometer, and yaw sensors

Low-cost off-the-shelf microelectromechanical system (MEMS) "air bag" accelerometers and solid state spin counting sensors were part of a fuze-configured instrumentation/telemetry package flown on an M483A1 projectile. These commercial sensor products are being evaluated under the U.S. Army's Hardened Subminiature Telemetry and Sensor Systems (HSTSS) program for their ability to survive in a high-g environment and support airborne, gun-launched munition testing measurements. The four-channel system included the magnetic spin counter, two axially aligned DC accelerometers, and a yawsonde. The accelerometers were used to measure the projectile's acceleration, the spin rate counter measured the projectile's roll rate, and the yawsonde measured the projectile's roll rate and angular motion to provide truth. Sensor data were transmitted during the flight to a ground station and then digitized. Sensor data from the flight test were reduced and compared to the yawsonde data, a 6-degreeof-freedom (6-DOF) trajectory simulation, and Weibel tracking radar data. All sensors survived the launch environment and provided data that had excellent agreement to the truth data. This paper describes the spin counter and accelerometer operation, discusses their many test and evaluation applications, and summarizes the flight test results. Introduction During the development and test of new projectiles and existing problematic projectiles, instrumented flight tests are often required to determine the projectile's aerodynamics, flight performance, and "This paper is declared a work of the U.S. Government and is not subject to copyright protection in the United States." stability. Since there are many different types of projectiles in the inventory and unused space within each projectile is at a premium, it is very difficult to instrument a 11 projectiles with a single telemetry package. Furthermore, these projectiles are subjected to a variety of launch and flight operating conditions depending upon the evaluations being performed. Therefore, gun-launched telemetry systems are limited by their size, performance, cost, and ruggedness. For years, custom measurement packages, developed by the Advanced Munitions Concepts Branch (AMCB) of the Army Research Laboratory (ARL) Weapons and Materials Research Directorate (WMRD), have been successfully used on board artillery and missile munitions to measure such physical behaviors as acceleration, spin rate, yawing motion, base pressure, and base temperature. Due largely to commercial technology breakthroughs, miniaturized sensors, transmitters, power supplies, and electronic packaging are now becoming available. The Hardened Subminiature Telemetry and Sensor Systems (HSTSS) program is a joint effort involving the U.S. Army Yuma Proving Ground (YPG), ARL-WMRD to identify and demonstrate a new generation of technologies to support airborne, gun-launched munition testing measurements for the Army and to all DOD agencies. The HSTSS effort is currently in the Concept Exploration and Definition phase of the acquisition cycle. The primary objective so far has been to assess the commercially available products that would form the HSTSS system. For the sensors, shelf microelectromechanical system (MEMS) technologies are currently being evaluated since they are smaller and less expensive than their predecessors. For example, this program will establish the