The Method Research that Far-field Calibration of Weather Radar based on The Combination of Objective Truth Value and Simulating Target

Calibration of weather radar is the foundation of data quality. Internal calibration, weekly maintenance, monthly maintenance and yearly maintenance ensure that stations of weather radar keep long-term stability. In fact, it shows that the echo intensity is not same between different stations of weather radar for same target, since the parameters obtained from the method of traditional calibration via theoretical calculation and measurement of radar subsystem. According to echo intensity calculation of weather radar equation, radar constant includes some parameters such as transmitted power, pulse width, antenna gain, beam width, system loss and so on. Accumulation of error from radar measurement causes the error between different weather radar stations. This paper researches a method that far-field calibration of weather radar based on the combination of objective truth value and simulating target, which combines far-field test, echo intensity calibration of standard metal ball, and calibration of simulating target. This method uses a device in far-field to receive radar signal to measure some parameters such as beam width, transmitted power, transmitter pulse width and so on; using the character of objective truth value of standard metal ball accurately calibrate that echo intensity and simulating target; and meanwhile, using simulating target generate an accurate and controlled signal in far-field to calibrate weather radar echo intensity, velocity, spectrum width, differential reflectivity factor, and differential propagation phase shift to make calibration of weather radar objectively and accurately.