Journal of Korea Society of Industrial Information Systems (한국산업정보학회논문지)

Korea Society of Industrial Information Systems (한국산업정보학회)
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Increment Method of Radar Range using Noise Reduction

잡음 감소 기법을 활용한 레이다의 최대 거리 향상 기법

  • 이동효 (한국항공우주연구원 위성정보센터 위성운영실) ;
  • 정대원 (한국항공우주연구원) ;
  • 신한섭 (한국항공우주연구원) ;
  • 양형모 (한국항공우주연구원) ;
  • 김상동 (DGIST 미래자동차연구부) ;
  • 김봉석 (DGIST 미래자동차연구부) ;
  • 진영석 (DGIST 미래자동차연구부)
  • Received : 2019.10.31
  • Accepted : 2019.12.06
  • Published : 2019.12.31
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Abstract

This paper proposes a method to improve the detectable distance by reducing noise to perform a signal processing technique on the received signals. To increase the radar detection range, the noise component of the received signal has to be reduced. The proposed method reduces the noise component by employing two methods. First, the radar signals received with multiple pulses are accumulated. As the number of additions increases, the noise component gradually decreases due to noise randomness. On the other hand, the signal term gradually increases and thus signal to noise ratio increases. Secondly, after converting the accumulated signal into the frequency spectrum, a Least Mean Square (LMS) filter is applied. In the case of the radar received signal, desired signal exists in a specific part and most of the rest is a noise. Therefore, if the LMS filter is applied in the time domain, the noise increases. To prevent this, the LMS filter is applied after converting the received signal into the entire frequency spectrum. The LMS filter output is then transformed into the time domain and then range estimation algorithm is performed. Simulation results show that the proposed scheme reduces the noise component by about 25 dB. The experiment was conducted by comparing the proposed results with the conventional results of the radars held by the Korea Aerospace Research Institute for the international space station.

본 논문에서는 수신신호에 신호처리 기법을 수행함으로써 잡음을 감소시켜 탐지가능 거리를 향상시키는 방법을 제안한다. 레이다의 탐지 거리를 증가시키기 위해서는 수신신호의 잡음성분을 감소시켜야 한다. 제안하는 방식에서는 두 가지 방법을 이용하여 잡음성분을 감소시킨다. 첫째, 다수의 펄스로 송수신된 레이다 신호를 하나로 누적시킨다. 이때 더해지는 횟수가 증가할수록 잡음의 무작위성으로 인해 점차 작아지지만, 신호 부분은 점차 커지는 특성을 이용한다. 둘째, 누적된 신호를 주파수 스펙트럼으로 변환한 후 LMS (Least mean square) 필터를 적용시킨다. 레이다 수신신호의 경우 대부분이 잡음 성분이므로, 시간 영역에서 LMS 필터를 적용할 경우, 오히려 잡음이 더 증가하게 된다. 이를 방지하기 위해 수신신호를 전체 주파수 스펙트럼으로 변환한 후 LMS 필터를 적용한다. 이후 LMS 필터 출력을 시간 영역으로 다시 변환하고, 거리 추정 알고리즘을 수행한다. 시뮬레이션 결과를 통해 제안된 알고리즘을 적용함으로써 잡음 성분을 25 dB 개선시킴을 보였다. 실험은 국제우주정거장을 대상으로 한국항공우주연구원에서 보유중인 레이다의 기존 결과와 제안된 결과를 비교분석하여 최대 거리가 약 1,000 Km이상 측정됨을 관찰할 수 있었다.

Keywords

References

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