Indian MST radar was established at Gadanki (13.46 N, 79.17 E) in southern India during 1987-1992 as a national facility for atmospheric research and was made available to researchers in India and abroad based on the demand of researchers under the Middle Atmosphere Program (MAP). The establishment of this radar facility was a national effort made possible with contributions received from the difference departments of the Government of India, viz., the Department of Electronics, Defence Research and Development Organisation, Department of Science and Technology, Department of Environment, Department of Space and the Council for Scientific and Industrial Research. The funding departments identified Indian Space Research Organisation as the nodal agency for establishing this facility. The Society for Applied Microwave Electronics Engineering and Research (SAMEER), Dept of Electronics was the prime contractor for the design and development of the radar system with the active participation of the major user agencies in the various stages of the design, development and validation effort. National MST Radar Facility (NMRF) was registered on January 11, 1993 as an autonomous society under Department of Space, Govt of India.
The MST radar is a high power atmospheric radar used for ground-based remote sensing of earth atmosphere for studies of dynamics and other physical processes in the regions of Mesosphere, Stratosphere and Troposphere (MST) covering up to a height of 100 Km. It is also used for coherent backscatter study of the Ionospheric irregularities above 90 km. MST radar is a state-of-the-art instrument capable of providing estimates of atmospheric parameters with very high resolution on a continuous basis, which is essential for the study of different dynamical processes in the atmosphere. This radar operates at 53 MHz with a peak power of 2.5 MW. The phased antenna array consists of two orthogonal sets of 1024 three element Yagi-Uda antennas arranged in a 32 x 32 matrix over an area of 130 m x 130 m. The two sets are co-located with pairs of crossed Yagis mounted on the same set of poles. The array is aligned along the geomagnetic axes to enable the radar beam to be transverse to the Earth’s magnetic field for ionospheric backscatter application. The array of either of the polarizations is illuminated using 32 transmitters of varying power, each feeding a linear sub-array of 32 antennas. The power distribution across the array follows an approximation to modified Taylor weighting in both principal directions. The radar beam can be positioned electronically at any look angle within ± 20 degrees off-zenith in the East-West and North-South planes at a resolution of 1 degree. It is possible to transmit both coded and un-coded pulses with pulse repetition frequency in the range of 62.5 Hz to 8 KHz, with a maximum duty of 2.5 %. Coded and un-coded pulse lengths can be varied from 1 to 32 µs with a baud length of 1 µs providing a range resolution of 150 m. The radar operates under instruction from a PC based radar controller that executes an experiment according to the experimental specification set by the user. Both time series and power spectrum data can be recorded on-line. The recorded data can be processed offline to derive various atmospheric parameters. Using this system in standalone mode and also along with other collocated instruments, many research studies have been conducted and reported. A list of publications using NARL facilities can be found on the publications page of the NARL website.