نوع مقاله : مقاله پژوهشی
نویسندگان
1 مالک اشتر
2 دانشجوی دکترای مخابرات دانشگاه صنعتی مالک اشتر تهران
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
The Synthetic Impulse and Aperture Radar (SIAR) considered as a Multi Input and Multi Output (MIMO) radar with different orthogonal carrier frequencies. SIAR is a four-dimensional (4-D) radar and has abilities such as safety against anti-radiation missiles (ARM), stealth targets detection, low probability of interception (LPI), multi targets detection and tracking and etc. In these radars, the phase of the received signals in the receiver is a non-linear function of range and angles, thus there is a coupling between the range and the angles. One of the most important challenges in these radars is coupling between range and angle. Due to this coupling, the range error causes the angle error and vice versa. To reduce coupling, radar designers usually design transmitting waveform based on carrier frequency coding. Previously, some methods such as designing waveforms based on sequential carrier frequency coding, positive and negative sequential carrier frequency coding and random carrier frequency coding were presented. In this article a new method under title of positive and negative random frequency coding is proposed. The geometrical and mathematical equations of coupling for a linear array are presented. Based on simulation results, it’s shown that proposed method reduces coupling and side lobe level by at least 3dB more than previous methods. It’s shown that the performance of the proposed method after integration in the receiver will be significantly better than previous methods. For example, after 10 pulses integration, the coupling decreases by more than 5 dB compared to the positive and negative sequential method. These improvements in the proposed method are achieved without imposing excessive and complex calculations. In addition, the frequency codes have a random distribution between transmitters, so the benefits of frequency agility are also obtained. Also, these improvements are achieved without imposing new and complex calculations.
کلیدواژهها [English]
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