Nenashev Vadim A, Nenashev Sergey A
Saint-Petersburg State University of Aerospace Instrumentation, 67, Bolshaya Morskaia Str., 190000 Saint-Petersburg, Russia.
Sensors (Basel). 2023 Jul 31;23(15):6835. doi: 10.3390/s23156835.
When forming the radar situation of a terrain, in order to increase its information content and to extract useful information, multi-position spatially distributed systems for integrating multi-angle radar data established by small-sized UAV-based airborne radars are used. In this case, each radar station belonging to a multi-position system as a probing signal must have its own unique marked signal. Such a setup will allow the signals reflected from ground objects and zones to be "attached" to specific receiving-transmitting positions of the multi-position system. This requirement results from the fact that each transceiver position emits one probing signal, and then receives all the echo signals reflected from the underlying surface and previously emitted by other radar devices of the multi-position system. Such a setup of multi-position systems requires the researcher to look for and investigate specialized systems of marked code structures used to modulate the probing signals in order to identify them in a joint radar channel. Thus, the problem at hand is how to look for and investigate novel marked code structures used to generate a system of probing signals, the use of which will allow it to be "attached" to a specific receiving-transmitting position of a multi-position onboard system and to identify them in a joint radar channel in the course of the remote sensing of the underlying surface. The purpose of this work is to conduct a study on the subject of the squeak and choice of a system of code structures that have a low level of side lobes of autocorrelation functions and uniformly distributed values of the levels of the cross-correlation function. To achieve this goal, the relevance of the study is substantiated in the introduction. The second section analyzes the level of side lobes for classical and modified Barker codes with an asymmetric alphabet. On the basis of this analysis, it was concluded that it is expedient to apply this approach for codes longer than Barker codes. Therefore, in the third section, the features of the generation of M-sequences are considered. The fourth section presents a technique for searching for new marked code structures, taking into account their mutual correlation properties for modifying M-sequences in order to implement multi-positional systems. The fifth section presents computer experiments on the search for marked code structures based on the modifications of M-sequences and presents the numerical characteristics of the correlation properties of the considered marked codes. And finally, in the sixth section, the final conclusions of the study are presented and recommendations are given for their further practical application. The practical significance of this study lies in the fact that the proposed new marked code structures are necessary for the synthesis of probing signals in the implementation of spatially distributed systems that function for the high-probability detection and high-precision determination of the coordinates of physical objects and are also necessary for the formation of radar images in a multi-position mode.
在形成地形的雷达态势时，为了增加其信息含量并提取有用信息，会使用基于小型无人机的机载雷达建立的用于整合多角度雷达数据的多位置空间分布式系统。在这种情况下，作为探测信号，属于多位置系统的每个雷达站必须有其自身独特的标记信号。这样的设置将使从地面物体和区域反射的信号能够“附着”到多位置系统的特定收发位置。这一要求源于这样一个事实，即每个收发器位置发射一个探测信号，然后接收从下垫面反射且此前由多位置系统的其他雷达设备发射的所有回波信号。多位置系统的这种设置要求研究人员寻找并研究用于调制探测信号的标记码结构的专门系统，以便在联合雷达信道中识别它们。因此，手头的问题是如何寻找并研究用于生成探测信号系统的新型标记码结构，使用这些结构将使其能够“附着”到多位置机载系统的特定收发位置，并在对下垫面进行遥感的过程中在联合雷达信道中识别它们。这项工作的目的是对具有低自相关函数旁瓣水平和互相关函数水平值均匀分布的码结构系统的选取和研究进行探讨。为实现这一目标，在引言中阐述了该研究的相关性。第二部分分析了具有非对称字母表的经典和修改后的巴克码的旁瓣水平。基于此分析得出结论，对于比巴克码更长的码应用此方法是合适的。因此，在第三部分中，考虑了M序列的生成特性。第四部分提出了一种搜索新的标记码结构的技术，考虑了它们用于修改M序列以实现多位置系统的互相关特性。第五部分展示了基于M序列修改搜索标记码结构的计算机实验，并给出了所考虑标记码的相关特性的数值特征。最后，在第六部分中，给出了该研究的最终结论，并为其进一步的实际应用提出了建议。这项研究的实际意义在于，所提出的新标记码结构对于在实现用于高概率检测和高精度确定物理对象坐标的空间分布式系统中合成探测信号是必要的，并且对于多位置模式下的雷达图像形成也是必要的。
