A Precision Height and Velocity Sensor for Airdrop Applications

Accurate estimations of the height and velocity of airdrop payloads are required to trigger soft-landing systems. These systems have a limited deceleration window, so robust and reliable estimations are required. Current systems rely on a 24-foot stick to trigger the deceleration. This approach is not ideal, and an electronic sensor would be preferable. 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 sodar sensor. In addition, we will investigate the value of fusing sodar data with data from other sensors in an optimal estimation algorithm to provide increased accuracy and reliability. In Phase I, we will select an optimum sensor suite based on a careful trade study of the cost and accuracy associated with different sensor component configurations. We will design a prototype height and velocity sensor incorporating the selected component set and prove its feasibility through a simulation based on measured component performance. In Phase II, we will build and test the prototype HVS at Creare and also in the field.