A Precision Height and Velocity Sensor for Airdrop Applications

Accurate estimations of the height and velocity of precision airdrop systems are required to control final deceleration maneuvers. Airdrop systems have a limited deceleration window, so robust and reliable estimations are required. Radar, sodar, and lidar sensors have been evaluated for this role with varying degrees of success. Foliage and vegetation prove troubling for many of the sensors. However, sodar has been shown to successfully penetrate ground vegetation at certain frequencies. Creare proposes to develop a lightweight, low-cost height and velocity sensor (HVS), which uses an optimal estimator to fuse sodar measurements with data from other sensors. In Phase I, we selected an optimum sensor suite based on a trade study of the cost and accuracy associated with different sensor component configurations. We designed a prototype height and velocity sensor incorporating the selected component set and proved its feasibility through a simulation based on measured component performance. In Phase II, we will further optimize the prototype design in a number of design/build/test cycles before developing a production design package for the sensor. At the completion of Phase II, we will have a sensor design ready to be fielded in precision airdrop systems.