RIS 100 Navigation Radar Intercept Sensor (NRIS)

Electronic Intelligence

The RIS 100 sensor is a Radar Electronic Support Measures (R-ESM) receiver that covers the International Telecommunications Union radar bands allocated to marine radar at X-band (RIS 100X) and/or S-band (RIS 100S). The sensor provides a bearing line, or "strobe", from the receiver location in the direction of any vessel at sea that is operating navigation radar in the defined frequency bands.

The accuracies delivered by the sensor allow for correlation between RIS 100 strobes, Automatic Identification System (AIS) reports and, if available, radar tracks to identify commercial shipping that have not activated their AIS transmitters.

When correlated with radar reports, the strobes provided by RIS 100 may confirm a vessel's presence if the radar detection reports are marginal due to, for instance, bad weather conditions compromising the radar's detection capability. The sensor may also provide early indication of a vessel approaching from over the horizon since the mast-head navigation radar may be detected before own radar detects the hull of the arriving vessel.

The accuracy of the strobes combined with the accuracy of frequency measurement allows multiple sensors with common sea coverage to unambiguously triangulate the location of vessels without AIS.