Wind profile measurement using lifting sensors

A vertical profile of wind velocity for use in rocket prelaunch operations should be measured rapidly in order to minimize the space-time displacement between the measured profile and the ascent trajectory. A lifting wind sensor, a missile-like body with a large cruciform or annular wing, can measure the wind profile below 100,000 ft in 10 to 15 min. Using the linearized equations of motion to determine the wind response transfer function, a sample configuration is shown to have a maximum resolution more than an order of magnitude better than that of a drag wind sensor, e.g., balloon, chaff, or parachute, with the same fall velocity. Although the maximum resolution is set by the ratio 2m_e/C_LαS_ρ, the amplitude and phase fidelity largely depend on the moment stability derivatives. The response to arbitrary profiles, computed with a three-degree-of-freedom trajectory program, supports the linear analysis. By employing an iterative technique, the accuracy of the wind-profile estimate can be increased by at least an order of magnitude. Preliminary flight test data are briefly discussed.