基于奥米亚棕蝇的仿生测向技术研究

Radio direction finding technology is not only widely used in the spectrum monitoring and interference source localization systems, but also play an important role in navigation, radio astronomy, disaster relief and other fields. The accuracy of direction finding technologies based on traditional interferometer and antenna array is mainly determined by the geometry dimension of antenna array. In the case of baseline length far smaller than the wavelength, the accuracy hardly meets the application requirement and even can't work effectively. According to biology research, the distance between two ears of Ormia ochracea is just about 1/140 of sound wavelength, but this insect is capable of reaching the accuracy of 2 degree based on a special structure in its auditory organ. With this bionic principle of Ormia ochracea’s phase difference amplification, some foreign researchers have obtained initial results in the design of short-wave direction finding antenna for single frequency. This project proposes the mathematical and electric circuit models by using the internal mechanism of short baseline biological direction finding, and then studies the equivalent noise figure of coupling structure and its restraining effect to the phase difference amplification, so that a parameters optimization method for better performance will be proposed. Furthermore, two direction finding simulation systems will be built on the basis of interferometer and antenna array, and the corresponding bionic direction finding algorithms should also be studied. The expected result of this project is to provide the theoretical and technological foundations for the practical use of bionic direction finding technology.

无线电测向技术广泛应用于电磁频谱监测、干扰源定位等领域，同时也在导航、射电天文、生命救援等方面发挥着重要作用。传统干涉仪和阵列天线测向技术，其精度主要决定于天线阵列的几何尺度，在远小于波长情况下，测向精度难以满足应用要求甚至无法有效工作。生物学研究表明，奥米亚棕蝇特殊的听觉器官结构，使其在双耳间距仅为声波波长的1/140时，仍然能够达到2度的测向精度。利用其放大相位差的原理，国外在单一频点的短波测向天线设计上已取得初步研究结果。本项目在短基线生物声学测向的内在机理研究基础上建立数学模型和电路模型，进而研究仿生耦合结构的等效噪声系数，及其对相位差放大的制约作用，提出以测向精度为设计目标的参数优化方法。在此基础上，以干涉仪和阵列测向构建仿生测向仿真系统，研究与之相适应的仿生测向算法。该项目的预期研究成果将为仿生测向技术的实用化奠定理论和技术基础。

测向技术在干扰源查找、救援、电磁频谱监测等方面具有广泛的用途。现有测向技术的发展，受制于精度和天线阵口径之间的矛盾，主要依赖于制造工艺和器件性能的提升，没有实现原理性突破。北美洲有一种寄生生物——奥米亚棕蝇，能够对寄主蟋蟀进行精度为2度的测向，其两耳间距仅为0.5mm，即波长的百分之一，远远超过目前测向技术的理论极限。本项目利用奥米亚棕蝇听觉器官力学结构研究成果，建立相对应的数学模型，通过研究其等效噪声系数和对相位差的放大作用，推导了该模型的测向精度理论极限，从而揭示短基线高精度仿生测向的内在机理，进而验证了奥米亚棕蝇听觉器官在蟋蟀叫声频点上具有逼近理论极限的测向性能。进一步将奥米亚棕蝇听觉器官模型迁移至无线电波频段，建立了仿生耦合结构电路模型，完成其参数取值，提出了基于高阶累积量的仿生测向算法，用以消除相关噪声对相位差估计的影响。在此基础上，针对干涉仪和阵列测向等典型应用，提出了模拟和数字两种仿生耦合结构实现方案，并进行了性能仿真和初步实验分析。本项目研究成果表明，将奥米亚棕蝇听觉器官放大相位差原理应用于无线电测向，通过数字方式实现参数优化设计可逼近仿生测向理论极限，相比于传统干涉仪测向精度提升超过75%，且能够提高阵列测向分辨率，测向精度相对于传统谱估计算法提升50%。该项目是对测向体制实现创新突破的尝试，预期研究成果将为仿生测向技术的实用化奠定理论和技术基础，进而广泛应用于频谱监测与干扰源定位。