ENIGMA IV

The powerful weather radar signal processor

GAMIC designs and manufactures ENIGMA IV, the advanced weather radar signal processor for single and dual polarization. It comprises two components – the intermediate frequency digitizer (IFD) converts your radar output to a stable and high quality digital signal while the host provides clean output data by applying powerful algorithms and corrections.

State-of-the-art signal processing hardware

The ENIGMA IV signal processor consists of a powerful host PC (ENIGMA PC) and a 19″ companion device called IFD (Intermediate Frequency Digitizer). The IFD can be installed either in an IT rack or head-mounted behind the radar antenna. It can be used in any common weather radar installation.

The IFD controls the transmit timing of the connected radar by applying trigger signals and performing the data acqusition accordingly. It comes with three separate input channels for horizontal, vertical, and burst (transmit signal / reference) signal measurement which enable full dual polarization capability. The IF signal is digitized at an intermediate frequency of 60 MHz (other frequencies optional) and the radar echo data is tagged with corresponding time and elevation/azimuth angle information. For optimum sensitivity and dynamic range a digital filter is applied which matches the transmitted pulse length perfectly. The generated raw echo data is provided to the host PC through an optical fibre connection of 1 Gbit/s for further processing.

The ENIGMA IV signal processor is very versatile and can be used for magnetron, klystron, or solid-state radars. In case of non-solid-state radars, the IFD is able to measure the IF frequency and apply an AFC (automatic frequency control) for proper receiving. For solid-state radars the complete output signal is generated by the IFD utilizing pulse compression technology.

ENIGMA IV Signal Processor - IFD backside

Powerful correction algorithms

To get the best out of your weather radar data, ENIGMA IV comes with powerful algorithms to ensure high data quality and reduced disturbances. Digital Doppler velocity processing enables more accurate velocity data and better clutter mitigation. The velocity based clutter filters provide 40 dB or better clutter rejection, resulting in less ground clutter. Dual polarization based rain and gas attenuation correction are inevitable for reliable rain rate retrievals, especially for sensitive X-band radars. Further data improvement features comprise the removal of multi-trip echoes, RF interferences, and sun spokes.

ENIGMA IV is highly configurable, including speckle remover (via reflectivity, velocity, spectrum width, or dual pol moment), thresholding (NOISE, CCOR, SIGPOW, RHOHV, SQI), and KDP interpolation.

New features for enhanced data

GAMIC’s signal processor ENIGMA IV just got better with some new features to get even more out of your data. Those new features include the following:

  • Fuzzy logic classification and flagging of range gates for ground clutter, multi-trip echoes, wind-turbine clutter, RF interference, and sun spokes
  • Improved random phase multip-trip detection and mitigation
  • Adaptive clutter filtering
  • Additional output moments (clutter phase alignment, standard deviation, SQI 2nd/3rd trip, classification flags, real and complex cross spectrum)
  • Improved thresholding including the new classifier flags

Comprehensive output moments

Besides typical single polarization radar moments reflectivity (Z), radial velocity (V), and spectral width (W), ENIGMA IV provides output of enhanced dual polarization moments which are essential for any contemporary processing and further usage of weather radar data. Those comprise ZDR, KDP, RHOHV, PHIDP, and much more. All radar moments are provided uncorrected and corrected.

For comprehensive data quality and signal analysis, ENIGMA IV serves some more output variables like signal-to-noise ratio (SNR), signal quality index (SQI), clutter power (CCOR), power spectrum (DFT), and more. For a non-exhaustive list of all ENIGMA IV output moments and further details, consider the ENIGMA IV datasheet.

Check out our weather radar software suite FROG-MURAN for generation of meteorological products and further data analysis tools.