MARG - Microwave Areal Rain Gauge
The estimation and quality of recorded rainfall play a vital role in the performance of the European sewer systems, water treatment plants, irrigation requirements and advanced recognition of a developing flood threat. Heavy rain frequently overwhelms urban sewage systems, which cause rapid flooding in cities. The unnecessary use of water for irrigation on farms increases costs significantly. Accurate, local level rainfall data is critical for customers of weather data service providers, as they can save multimillion euros on rainfall related investment for improving these systems.
Currently, the common methods to measure rainfall include the use of rain gauges or long range weather radars. Rain gauges are used for direct measurement of rainfall intensity near land. As rain gauge measures precipitation in one single point, a network application of gauges is necessary to keep deviation below an acceptable value which causes high costs. Rain gauge networks are often poorly designed and sited which result in unreliable data that cannot be used. Long range weather radars work as very densely situated rain gauges, but the price of long range weather radars is not affordable for large part of end-users, especially for SMEs.
Participating SMEs of the MARG project realized that there is a clear need for a cheaper and innovative measurement device. The MARG project aims to develop an innovative, accurate, real-time and user friendly measurement system monitoring spatial distribution and intensity of rain in rural and urban scale for commercial weather data and value-added forecast product suppliers.
The MARG radar is a so called FMCW (frequency modulated continuous wave) radar. That means the radar is continuously transmitting and the range to the target (in this case rain-cells formed by a huge amount of single ) drops is determined by the difference in frequency between the transmitted and received signal. Because the transmitter and receiver are therefore switched on the whole time 2 seperate antennas are used to minimize the negative impacts of direct coupling. The center frequency of the radar is at 5625 MHz with a bandwidth of 50 m resulting in a range resolution of 50 m.
The advantage of a FMCW system compared to a pulsed radar - which is used in long range weather radars - is the much lower peak power needed. In the case of the MARG radar the transmitted power is 20 W (compared of a few hundred kilowatts of a typical pulsed radar). The maximum range is about 30 km.
The antennas have a 3 dB-beamwidth of about 3 ° resulting in a cross-range resolution of about 1500 m at a distance of 30 km.
Our institute developed crucial parts of both hard- and software.
The hardware part included the whole radar-frontend consisting of
The open case of the frontend is shown in the figure.
The software consists of algorithms for signal-processing implemented in a FPGA but also the application for data-processing running on an ARM processor-core. The later provides also a simple visualisation.
EU / FP7
1.11.2012 - 31.10.2015
EU project homepage