适应于声相关海流剖面仪的单脉冲发射信号设计

声相关海流剖面仪(ACCP)利用“波形不变性原理”进行测速,能够测得相对海底的绝对速度。相对于多脉冲发射体制,文章采用脉宽足够长的单脉冲进行发射,既增加了发射能量,提高了海底探测的深度,又保证了系统带宽的要求。单脉冲脉内采用相位编码,减少了测速噪声的影响,通过一个满足相关寻优准则的编码搜寻程序进行伪随机编码,编码长度与声相关延迟时间相一致,所产生编码的自相关函数具有双相关峰特性,这与双脉冲发射的测速体制相对应,解决了双脉冲发射体制测速中脉冲宽度和脉冲间隔时间之间的矛盾。

Waveform design for acoustic correlation current profiler

The principle of waveform invariance is used in measuring velocity of an acoustic corr-elation current profiler(ACCP) with bottom tracking capability to provide vessel-earth relative velocity.A single transmitted pulse with a sufficiently long duration is used to increase energy of the pulse packet and the operating range while maintaining a large bandwidth.The pulse is coded with phase coding for reducing noise variance.The coding technique involves pseudo-random codes generated by an optimal code finding program.The code length is specified with a desired time delay for correlation.The pulse has an additional autocorrelation peak at a predetermined time lag to give a function of dual peaks.Trade-off between pulse width and pulse interval is thus obtained.