The LETVIS EXT/S is a high performance radar processor which transforms primary radar video outputs – from virtually any air surveillance radar – into high quality digital target reports or track messages suitable for integration into modern control centres. The LETVIS EXT/S is modular in design and can be configured in any combination of primary radar or weather extractor. The system is interfaced to a control and maintenance console to provide real-time PPI and weather information while providing complete system monitoring, maintenance and recording functions.
The LETVIS EXT/S software includes a field proven and certified (ATS, CAA of the Slovak Republic, and the Armed Forces of the Slovak Republic) Sensor Data Processor which dramatically reduces radar false plots from weather, bird flocks, road traffic, ground clutter and anomalous propagation. Additional data processing features include primary/secondary radar plot association, message filtering and coordinate transformations.

The LETVIS EXT/S is designed with user configurable format and protocol capabilities providing for highly effective data translation and distribution functions. The product supports a multitude of protocols (e. g., synchronous, asynchronous, HDLC), electrical standards (e. g., RS-232C V.24, RS-422, ETHERNET 802.3) and ASTERIX message format. New formats can be added to meet customer needs.

The Radar Data Extractor (RDX) extracts digital target information by primary radar video processing. The RDX is designed to accommodate scan rates and signal bandwidths of both short and long-range radars and utilize both normal and MTI video signals. After parallel A/D conversion of a radar´s normal and MTI video signals, the RDX performs non-coherent integration and applies fixed and adaptive thresholds to maintain a constant false alarm rate. It detects targets via M-of-N sequential observer process derived from a rank-value back-ground-normalizer and high-resolution clutter map. This eliminates „splitting“ a single range-extended target, and „merging“ two targets occupying adjacent azimuth cells. All processing functions are fully configurable to satisfy specific customer needs.

- Processing Channels: Parallel independent processing of normal and MTI video with range-azimuth gating
- Radar Video Sampling: 10-bit A/D conversion; up to 20.0 MHz sample rate
- CFAR Processing: Ordered-statistic background normalize; range-varying threshold map; integral clutter map
- Detection Capacity: Up to 1,000 detections per second
- Adaptation processing: Automatic adaptation to environmental conditions
- Target Capacity: Up to 1,000 reports per scan
- Accuracy Performance:
- Range accuracy = 30m;
- Azimuth accuracy = 0.2° (for 1.5° beamwidth)