中文摘要：

本文讨论水下辐射噪声源的精确定向问题，给出被动声纳和波束定向与分裂波束定向方法的性能比较。指出在一定信噪比下，分裂波束精确测向技术比和波束定向技术具有较高的定向精度。但是，随着信噪比的下降，两者趋于一致。推导了估计定向精度的分析表达式，给出在直线阵和圆弧阵情况下，延时估计和声源入射角偏差之间的换算公式和数值模拟结果。同时给出数字式声纳用以计算入射信号左波束和右波束数据的互谱来实现分裂波束定向的方法。

英文摘要：

Precise bearing of underwater noise source is discussed in this paper. The performance comparison of the sum beam steering and the split beam steering methods in passive sonar is presented. It is shown that, in a certain range of signal to noise ratio, the bearing accuracy of split beam method is much better than the method of sum beam. But with the decrease of signal to noise ratio, the performance of two methods become same. The closed form expression of bearing accuracy of the two methods for estimating DOA （Direction Of Arrival） of the target is derived. In the case of line array or arc array of a sonar system, the relationship of time delay and the bias angle of incidental signal is presented. Some results of system simulation are illustrated. An algorithm is given, which calculate the cross power spectrum of left beam and right beam data for realizing the split beam bearing in digital sonar.