Report
АДАПТИВНАЯ КОМПЕНСАЦИЯ АМПЛИТУДНЫХ И ФАЗОВЫХ ИСКАЖЕНИЙ, ВНОСИМЫХ АППАРАТУРОЙ РСА В ПРИНИМАЕМЫЙ СИГНАЛ
| Title: | АДАПТИВНАЯ КОМПЕНСАЦИЯ АМПЛИТУДНЫХ И ФАЗОВЫХ ИСКАЖЕНИЙ, ВНОСИМЫХ АППАРАТУРОЙ РСА В ПРИНИМАЕМЫЙ СИГНАЛ |
|---|---|
| Publisher Information: | Радиотехнические и телекоммуникационные системы, 2022. |
| Publication Year: | 2022 |
| Subject Terms: | frequency-shift keyed signals, amplitude-phase signal distortions, радиолокатор с синтезированием апертуры антенны (РСА), ампли-тудно-фазовые искажения сигнала, компенсация искажений, частотно-манипулированные сигналы, SAR (synthetic aperture radar), distortion compensation, автокалибровка, autocalibration |
| Description: | SAR (synthetic aperture radar) is examined where FSK (frequency-shift keyed) signals are used to obtain high resolution in range. Using FSK signals in SAR goes along with distortions emerging in recieved signal which are due to dependence on amplitude frequency and phase of through transmission ratio of signal path, including transmitter, antenna and receiver. Amplitude-phase distortions are hard to account for due to randomness and temporal variability of their manifestations. The paper is aimed at adaptive algorithm development for evaluating and compensation for signal amplitude-phase distortions caused by SAR equipment, as well as at verification of its performance in synthesizing radar images in SAR. Synthesis of compensation algorithm is done in two steps and it is for a complex signal, which is compressed in azimuth coordinate and is represented by module and ar-gument (phase). First, signal module is evaluated by averaging amplitudes throughout RF hologram according to maximum likelihood criterion. Second, the phase is evaluated using non-parametric iteration autofocusing algo-rithm which is optimal as per minimum variance criterion. Complex vector was obtained as a result, which is used to compensate for amplitude and phase distortion. The developed autocalibration algorithm performs real-time distortions’ evaluation and compensation. Block diagram synthesis is done, which implements the pro-posed adaptive algorithm. Algorithm research results in laboratory and flight environment are prsented. It is made clear that powerful sidelobes at –15 dB level are observed if amplitude-phase distortions are in the signal. Such sidelobes in RI (radar images) make false marks, deform radar targets, disguise marks of small-size low-reflection targets. Flight tests with airborne Ku-band SAR testified that using developed algorithm enabled to re-duce the level of maximum sidelobe down to –39 dB and boost quality of synthesized RI. Proposed algorithm capabilities are noted for processing operations’ automation of RF holograms and radar images’ decryption. Устранение в обрабатываемом сигнале амплитудно-фазовых искажений, вызванных зависимостью коэффициента передачи от частоты, является необходимой процедурой в алгоритмах картографирования с субметровым разрешением, особенно при использовании частотно-манипулированных сигналов. В статье рассматривается алгоритм, в реальном масштабе времени выполняющий оценку и компенсацию этих искажений и позволяющий получать качественные радиолокационные изображения с субметровым разрешением. Приведены описание алгоритма и результаты его исследования в лабораторных и лётных экспериментах. |
| Document Type: | Research |
| DOI: | 10.24412/2221-2574-2022-2-42-49 |
| Rights: | CC BY |
| Accession Number: | edsair.doi...........be4a483adef4094e2ba7b10e696b6225 |
| Database: | OpenAIRE |
| DOI: | 10.24412/2221-2574-2022-2-42-49 |
|---|