Calibrating Ka Band Satellite Down-Link Modem Measurements for Rainfall Monitoring

The observation of the signal level in microwave satellite links for remote sensing of rainfall can be a useful complement for existing sensors such as rain gauges or weather radars. The number of very small aperture terminals (VSATs) that provide internet connectivity is constantly rising. As such terminals are more and more used in corporate networks, the VSAT density is increasing- not only in remote areas. When retrieving the rain rate from signal measurements, the quality of the signal measurements has to be investigated. This study compares signal measurements of two common types of co-located terminals with a reference demodulator. It shows both over- and underestimation of various modems and provides a correction function for the values. This analysis lays the foundation for using these types of VSATs for retrieving rain information and also has benefits for satcom network operators.