The Chilbolton Observatory Kepler radar is a MIRA-35 scanning pulsed Ka-band radar developed by METEK. It is used to detect clouds, fog, and precipitation in the atmosphere. It is a mobile scanning radar typically operating at 35.1GHz or a wavelength of 8.55mm. It can also operate at 33 – 37 GHz, depending on available spectrum. It is a Doppler radar with high sensitivity allowing observation of very thin clouds. It is a dual polarisation radar, and has the ability to differentiate between differing rain rates, hail, snow and sleet. It can determine the size, shape and variety of precipitation and can identify the melting layer.

The radar operates with a 1m antenna. The antenna and radar electronics are mounted on a two-axis positioner to enable scanning in both the azimuth and elevation directions. The scanning is capable of elevation scanning within zenith angles from -90 to +90 degrees and azimuth angles from 0 to 360 degrees (with continuous rotations). The radar is mounted on a trailer to enable radar mobility for different locations.

Radar Specifications

Transmit frequency: 33 – 37 GHz, 35.2 GHz recommended by ECC
Peak power / average power: 30kW / 30 – 60W
Sensitivity: -53 dBZ (5 km range, 30 m range resolution and 10s time resolution, 1m antenna)
Maximum measuring range: Up to 40 km, epending on pulse width and and pulse repetition frequency
Minimum measuring range: 150 m
Maximum number of range gates: 800-1000
Minimum time resolution: 0.1s
Beam width: 0.58° with 1 m antenna
Antenna diameter: 1 m
Pulse width: 100 – 400 ns
Pulse repetition frequency: 2.5 to 10 kHz
Velocity resolution: 5 cm/s
Polarization parameters: Linear polarization on transmit, co- and cross-polarized signals are received simultaneously. Linear depolarisation ratio and co–cross correlation can be computed.