Based On The Side-lobe Cancellation Technology Of Satellite Design And Research Of The Anti-interference Mechanism

Adaptive sidelobe cancellation technique is an important branch of the anti-jamming technology. It can effectively suppress blanket jamming and has been widely used in the fields of radar, satellite, etc. In this paper a mixed Analog-Digital module of sidelobe canceller(SLC) for a certain type of satellite is proposed. It calculates adaptive weight values in the digital domain and suppress blanket jamming in the analog domain, which doesn’t need significant modification to the structure of original system.The main works of this dissertation are as follows:1、The paper analyses the device modules in detail including the cancellation of the main channel module, auxiliary channel modules, the algorithm module and the amplitude and phase weighting module.2、The number and location of the auxiliary array elements are important aspects of the adaptive sidelobe cancellation technology. In the paper we find the optimal position and number of array elements to meet practical requirements though theoretical analysis and computer simulations.3、Adaptive algorithm plays a key role in evaluating the performance of the system. We investigate the principles and functions of several typical adaptive algorithms such as SMI, LMS and RLS. By weighing the difficulties in engineering implementation and performance, we finally decide to adopt the combination of SMI and LMS. In this paper we first calculate the initial value of the weights using SMI algorithm, then perform a series of iterations to compute the converging weights using LMS algorithm.4、The power and incidental direction of jamming signal as well as the amplitude and phase discordance will also impact the performance of the system. Concerned with these issues the paper analyses them carefully and concludes that the stronger the interference-signal power rate(ISR) the better the effect of interference suppression of the system. Interfering signal incident direction problem is equivalent to the power of the signal. The differences of amplitude and phase between channels have a negative effect on the system. LMS algorithm could correct the consequences caused by channel disaccord to some extent while SMI algorithm is more sensitive to it.5、In LMS algorithm process, restricting the weights can improve the system robustness, which is also analyzed and verified in the paper.6、A/D quantization brings the loss of cancellation ratio (CR), in this paper we also analyze the influence of quantization.