A standalone application to monitor the stability of a low cost maintenance free X-band mini weather radar, using ground clutter echoes

During the past years, the Remote Sensing Group of Polytechnic of Turin developed a prototype of a X-band mini weather radar, capable to detect and measure rain with good space and time resolution. These radar systems may suffer for some degradations due to external factors like temperature fluctuations: some adjustment should be automatically implemented through a periodic control procedure, in order to have a continuously correct rainfall estimation. An application to monitor the X-band mini weather radar is presented. The basis of the proposed methodology is to control the radar signal stability trough a statistical analysis of clutter echoes coming from a multiplicity of ground targets during clear sky days. This application has been designed as a standalone software, which can be periodically run by a radar user and which can be fully integrated within the common radar control and signal processing software. The application allows analysis on a short term or on a long term period. The short term analysis tracks the mean clutter value variations evaluated considering six circular concentric crowns around the radar, in order to take into account the clutter behavior at different distances. It is useful to monitor the radar signal with respect to the temperature fluctuations. The long term analysis is based on an adapted version of the RCA (Relative Calibration Adjustment) proposed by D.S. Silberstein et. al. in an article published in 2008 (Journal of Atmospheric and Oceanic Technology), which works on the cumulative distribution function of radar reflectivity. The application has been already installed onboard on two radar systems and both the short term and the long term period analysis have been performed achieving good results.