Application of Complementary Codes in Ionosphere Sounding

Ionosonde usually uses m-sequence or Barker codes to code the pulse,but what's undesirable is that high sidelobe peak level(PSL) exists after pulse compression.Using complementary codes as phase codes in areas where Doppler shift is weak is proposed.Complementary codes has superb autocorrelation characteristics as summation of autocorrelation of A,B code sequence has no sidelobe.But A,B coded pulses are not transmit simultaneously,Doppler shift degree the pulse compression capacity of complementary coded pulse.Simulation shows that: when Doppler shift is weak,complementary coded pulse has superior pulse compression capacity than m-sequence and Barker codes coded pulse,and when Doppler shift is severe,pulse compression capacity of complementary coded pulse degree seriously.