Pulse doppler measuring apparatus

Abstract

The present invention relates to a pulse Doppler measuring apparatus using the so-called acceleration method. In order to prevent production of a secondary aliasing (where a phase vector is subjected to an aliasing), the apparatus is provided with an MTI filter, which decomposes a first phase vector of a reflected wave obtained by mixing a reflection signal with a reference signal into a real part and an imaginary part, obtains a first regression line for variations of each of the parts and extracts a second phase vector corresponding only to the high frequency component of the reflected wave by calculating differences of the real part and the imaginary part from the first regression line; and/or an angular component .DELTA..theta. of the phase difference vector is obtained; a second regression line is obtained for this phase difference angle .DELTA..theta.; and the phase difference angle .DELTA..theta. is corrected by using this second regression line, to prevent the production of a secondary aliasing.