Coherent Power Measurements with a Compact Airborne Ka-Band Precipitation Radar (KPR)

Coherent Power (lag-1 auto-correlation or dual-pol lag-0 cross-correlation magnitude) is an alternative to the commonly used noise subtracted power technique for measuring weather radar received signal power. The inherent noise cancelling feature of coherent power eliminates the need for estimating and subtracting the noise component from low signal to noise ratio signal plus noise measurements. This is particularly useful with weather radars that average a high number of samples to improve sensitivity and collect much of the data well below unity signal to noise ratio, where the required accuracy of the estimated noise component is increasingly difficult to achieve. This paper describes the University of Wyoming airborne solid state Ka-band Precipitation Radar (KPR) and compares the conventional power and coherent power measurement techniques by investigating measurement bias and probability of false alarm and detection rates at various SNR and threshold levels using analysis, simulations and cloud and precipitation data.