Abstract: In broadband Doppler current measurement, in order to search and identify different types of targets while testing current velocity , traditional transmitted signals usually adopt a continuous coding form and last for a long time. This results in effects from the center peak of the autocorrelation function and side lobes, which can be mitigated. Therefore, this article introduces the use of orthogonal complementary coding. First, orthogonal coding can reduce the standard deviation of velocity measurements to some extent. Then, complementary coding is introduced into the continuous coding signal segments. The ambiguity function of the complementary coding form has the advantage of a narrower mainlobe width and almost no sidelobes at high mainlobe amplitudes, which enhances the signal’s anti-aliasing properties. Through simulation studies, it is proven that the standard deviation of velocity estimation with orthogonal complementary coding signals shows significant improvement compared to traditional methods, demonstrating robustness to noise and achieving gains in signal-to-noise ratio, thereby extending the measurement range.