Application of the linear discrete filter to the processing of meteorological rocket wind data

A number of meteorological rockets with _ dropsonde and metallised parachute payloads were fired at Woomera, South Australia in 1968. The parachutes were tracked by the Commonwealth Bureau of Meteorology's WF 44 radar to permit determination of temperature profiles (using the telemetered temperature data) and wind profiles. Smoothed position, velocity and acceleration data were required in order to allow for poor wind sensor response at the highest altitudes. Smoothing was achieved using the Linear Discrete Filter which is based on the assumption that the acceleration is constant. Some properties of this filter are discussed and error estimates for the smoothed data are derived. It is shown that with smoothing extending over about three-quarters of a minute and with an input rate of one point per second, satisfactory profiles can be determined with an accuracy of a few meters per second.