RADAR RECEIVER

PROBLEM TO BE SOLVED: To provide a radar receiver less expensive and smaller than conventional ones.SOLUTION: A radar receiver 20 receives a question wave at 1030 MHz transmitted by an SSR transmitter/receiver and a response wave at 1090 MHz transmitted by a transponder of an airplane, and determines the position of the airplane. At that time, the radar receiver performs mixing of the question wave and the response wave at different frequencies with a local wave at the central frequency of those frequencies (1060 MHz) and converts the frequencies of the question wave and the response wave into the same intermediate frequency (30 MHz), and whereby it can receive the question wave and the response wave by using one reception antenna 20A and reception circuit 22.SELECTED DRAWING: Figure 2 【課題】従来より安価でかつ小型のレーダ受信機を提供する。【解決手段】レーダ受信装置２０は、ＳＳＲ送受信機から送信される１０３０［ＭＨｚ］の質問波と航空機のトランスポンダから送信される１０９０［ＭＨｚ］の回答波とを受信して、航空機の位置を特定する。その際、周波数が異なる質問波と回答波とをそれらの周波数の中央の周波数（１０６０［ＭＨｚ］）のローカル波でミキシングして質問波と回答波とを同じ中間周波数（３０［ＭＨｚ］）に変換するので、質問波と回答波を１つの受信アンテナ２０Ａ及び受信回路２２で受信することができる。【選択図】図２