Radar CLUTTER-FREE forecasting EXHIBITOR -BOOTH A500 Mrinal S Balaji, chief radar scientist, Baron Weather P Baron Weather explores a new approach to mitigating Doppler dilemma within polarimetric weather radars Staggered PRT processing in the Baron Weather processing suite olarimetric Doppler weather radars can provide high-quality wind data at a high spatial and temporal resolution. This kind of data is of great value for operational weather forecasting and numerical weather prediction (NWP) models. Doppler velocity information can be used for removal of ground clutter, extraction of wind profiles, detection of shear zones and construction of dual-Doppler wind fields. In addition, the wind profiles and radial velocity data can be assimilated into NWP. Operational application of Doppler data from weather radars is hampered, however, by the infamous limitation of the range-velocity ambiguity. Doppler radars transmitting uniformly spaced pulses suffer from coupling between the unambiguous range ( r a ) and maximum de-aliasing velocity ( v a ). This limitation, known as the Doppler dilemma, is given by the equation r a v a =c λ /8, where c is the speed of light and λ is the radar wavelength. This is particularly severe as the radar wavelength decreases. One way to address this challenge is through the use of staggered pulse repetition times during transmission, T 1 and T 2 ( T 1 < T 2 ), and then using the received return echoes to extend the maximum de-aliasing velocity by a factor of 1/{( T 2 ⁄ T 1 ) -1}. The application of this staggered pulse repetition time (PRT) technique has been hampered until very recently by the inability of most operational weather radars to efficiently filter ground clutter while processing data collected in this mode. This article intends to concisely introduce Baron Weather’s (Baron) solution to combat this limitation within polarimetric weather radars at S-, C-and X-band transmission frequencies by effectively blending traditional signal processing techniques like staggered PRT processing with innovative technologies like CLutter Environment ANalysis using Adaptive Processing (CLEAN-AP 2009 Board of Regents of the University of Oklahoma, USA) that are well suited for clutter mitigation within this mode. The Baron Processor Suite employs Data Distribution Service (DDS), the first middleware standard that addresses challenging real-time requirements needed to perform staggered PRT processing” In recent years, staggered PRT processing has emerged as one of the most suitable candidates to address the mitigation of range and velocity ambiguities in polarimetric Doppler radars, leading to Baron making the decision to incorporate it within its processing suite. The Baron Processor Suite employs Data Distribution Service (DDS), the first middleware standard that addresses challenging real-time requirements needed to perform staggered PRT processing. It can handle very-high-performance communications and is currently employed within applications like NASA’s robotic applications, financial high-speed trading, advanced telescopes, medical imaging, air-traffic control, smart grid management and several other big data applications. Within the Baron Processor Suite, the user can define various types of scan strategies to collect operational data including pulse position indicator (PPI) scans, range height intensity (RHI) scans and point scans that collect and process data using the staggered PRT mode of processing. During staggered PRT processing, the pulse repetition time ratio T 1 / T 2 = k m /k n is typically less than 1 and larger than 1/3, where k m and k n are relatively prime numbers. This allows for an extended maximum unambiguous velocity of v a = k m λ /4 T 1 = k n λ /4 T 2 , where λ is the radar wavelength. The user has the option to select the staggered PRTs in 2/3, 3/4 and 4/5 ratios while defining the scan strategies. The signal processing mode is then used to extract different measurements of range, azimuth/elevation, radial velocity, spectrum width and polarimetric characteristics of the September 2025 • www.meteorologicaltechnologyinternational.com • 81
Meteorological Technology International Meteorological Technology International September 2025 Issue: Page 81
