Mitsui Shipbuilding & Engineering Co., Ltd.

Kyoritsu Dempa Co., Ltd.

Hiroharu Nishiguchi

Takamura Takigawa

Kazunori Kitasumi

Sueichi Tsuruta

Shiro Hikawa

In a PPI display type radar system wherein a sector shaped unit scanning surface is established in a scanning plane and a unit scanning surface is shifted progressively in the radial and circumferential directions to seach the received pattern for judging a target. The received pattern is identified by dividing the unit scanning surface into a plurality of annular sections derived from a plurality of concentric circles. The scanning unit for scanning surfaces having approximately the same area over the entire scanning surface is designed in such a manner that the ratio (percentage of extraction) of a number of sampled scanning beams to the number of actual scanning beams is a maximum when scanning an annular section which is located most remotely from the center. The percentage of extraction is gradually decreased toward the center so that the percentage of extraction becomes a minimum 1/n (where n is an integer) when scanning an annular section closest to the center. Scanning the received signal in each unit scanning surface with a scanning beam at equal numbers in the radial and circumferential directions and at substantially the equal spacing obtains a pattern of the received signal in accordance with the presence or absence thereof, and the target may be judged in accordance with the size of the pattern.

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Tokyo, Japan

Hiroharu Nishiguchi