Scale factor considerations for SDF technique

The Tasman International Geospace Environment Radars (TIGER) form part of an international network of similar HF radars called Super Dual Auroral Radar Network (SuperDARN) which explore the impact of solar disturbances on Earth. These radars utilise an Auto Correlation Function (ACF) to measure the changing phase of the ACF between lag times to determine the Doppler frequency and the target velocity.With the development of TIGER-3, an all digital radar platform, a novel method of determining target velocities has been proposed. In the proposed method, a comparison of the transmit and receive signal magnitude spectrums is performed to determine the Spectrum Difference Function (SDF). The gradient of SDF in the vicinity of the carrier frequency is calculated, from this value the Doppler Frequency Shift fd can be deduced. The result is then multiplied by a precalculated Scale Factor which is necessary to compensate for the systematic error due to the method. This paper will address all the factors which have influence on the value of Scale Factor, therefore minimize the error associated with the process of calculating Scale Factor.