中文摘要：

为在武汉电离层斜向返回探测系统（Wuhan ionospheric oblique backscattering sounding system，WIOBSS）中实现低的发射功率、远的探测距离、比较强的抗干扰等技术要求，根据wIOBSS的特点，提出了脉间二相编码等间隔收发探测模式。在这种新型探测模式中，WIOBSS采用发射长持续时间探测信号的方式来积累回波能量，并采用具有良好自相关性的二元伪随机序列m序列和近完美序列来对相位进行调制。另外，一套采用软件无线电和面向仪器系统的外围部件互连扩展（Pci eXtension for instrumentation，PXI）总线技术的软件化发射模块被设计用于实现这种新型探测模式。实际探测结果表明，采用该发射模块的WIOBSS在发射功率非常小的情况下成功地实现了2000km范围内的电离层状态探测。

英文摘要：

To meet the technical requirements of low transmitting power, long sounding distance, perfect anti-interferenee for wuhan ionospheric oblique baekscattering sounding system （WIOBSS）, a new sounding mode of binary phase-coding, transmission and reception in equal interval is introduced according to the charac ter of WIOBSS. In this sounding mode, the sounding signal with long duration is emitted to integrate the power of echoes in WIOBSS. Furthermore, the pseudo-random codes with perfect autocorrelation function, such as m sequence and almost perfect sequence, are adopted to modulate the phase of emitted signals. In addition, according to the techniques of software radio and Pci extension for instrumentation （PXI） bus, a set of soft- ware-based transmitting module is designed to realize this new sounding mode. The experimental results show that with this transmitting module, WIOBSS successfully achieves the sounding of ionosphere condition in the range of 2 000 km under very low transmitting power.