Radar tracking of sea-skimmers, an implementation of `complex angle´

Many attempts have been made to solve multipath problems, in particular at sea for defence against sea-skimming anti-ship missiles at altitudes down to, perhaps, 3 m. One of the methods investigated in the late 1960s was the `complex angle´ described by Sherman (1971). The present paper can be regarded as an extension of this method by using the particular properties of the NobelTech Ku-band 9LV Mk3 Director-Tracking Radar. Like the original `complex angle´ it should have limitations due to the diffuse component of the reflection coefficient becoming a dominant error source at larger grazing angles and higher sea-states. However, the method is primarily developed for use with low-sited antennas on relatively small ships and targets at the very lowest altitudes. The method has been investigated theoretically by calculations and simulations and tested experimentally against low altitude targets of two different types