Accurate Ranging of Dual Wavelength FMCW Laser Fuze Under Different Types of Aerosol Interference

Laser fuze has the advantages of high distance accuracy and strong anti-electromagnetic interference capability, but it is easily disturbed by aerosols, such as smoke, which hinders its detection performance and application. This article proposes the dual wavelength frequency-modulated continuous wave (FMCW) laser detection technology as a solution. Compared with the single-wavelength FMCW laser fuze, the detection performance and the target recognition ability are enhanced under severe interference. First, the principles of dual wavelength FMCW laser detection are analyzed, followed by a block diagram of the fuze system. Second, the single scattering attenuation characteristics of spherical aerosol particles in reaction to different wavelengths of laser beams are discussed, and the scale distribution and complex refractive index characteristics and laws of four typical aerosol particles, including soot, ocean, dust, and water soluble, are analyzed. Finally, the echo characteristics of 0.3- and 10.6- $\mu \text{m}$ wavelength laser beams with or without a target are simulated and analyzed under the condition of typical aerosol heavy interference, and the spectral characteristics of the beat signal of the dual wavelength laser echo are obtained. According to this characteristic, a system for target recognition and distance determination using a dual-wavelength FMCW laser beam against aerosol interference is designed. The simulation results indicate that, in the presence of severe interference, the proposed system can effectively distinguish aerosol interference from the target and realize the accurate distance of the target.