Design and Analysis of Interpulse Frequency Coded and Intrapulse Composite Frequency Modulation Radar Signal

‍ ‍Modern battlefield environment was complex and changeable. In addition to having higher target resolutions to complete the target detection tasks， airborne radar should also have good Radio Frequency （RF） stealth performance such as large time-bandwidth product， low interception factor， low power spectrum amplitude， uneven spectrum and maximum uncertainty. In order to design well-performing RF stealth waveforms， based on the time-frequency characteristics of the interpulse Costas and intrapulse Costas （Costas-Costas） signal， while maintaining the frequency agility between the sub-pulses of Costas， the hybrid frequency modulation mode of Costas frequency coded and Nonlinear frequency was adopted in the sub-pulses and the interpulse Costas frequency coded and intrapulse Costas and NLFM composite frequency modulation （Costas-CN） radar signal was obtained. Compared to the single modulated signals， Costas-NLFM signal and Costas-Costas signal， Costas-CN signal greatly increased the complexity of the intrapulse frequency modulation features and increased the difficulty of sorting and identifying signals in passive detection systems. Simulations show that Costas-CN signal improved in ambiguity function， autocorrelation properties， power spectrum density and interception factors. While realizing radar detection， the signal also has good RF stealth performance， which has a wide application prospect in modern war.