One fundamental aspect in designing a good radar system is the performance of range resolution. The good range resolution performance is required in radar system to detect small targets at a long distance. It is already known that the longer pulse will increase energy and improve target detection. Conversely, shorter pulse will increase the range resolution of radar. Recently, one pulse compression technique frequently used is linear frequency modulated (LFM) pulse wave. This paper presents the LFM pulse compression technique for improving radar performance and its simulation in Matlab and GNU radio using audio and radio waves. The performance of radar resolution using LFM pulse compression technique is observed from the parameter of pulse compression ratio (PCR). A higher PCR value indicates a better radar resolution. From the result, it shows that the values of PCR in Matlab R ⃝ simulation using audio and radio waves are 6000 and 300000, respectively. Moreover, in GNU radio implementation, the values PCR using audio and radio waves are 0.275 and 50, respectively.

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Teknologi telekomunikasi berkembang begitu pesat, dari yang semula berkomunikasi menggunakan surat, berkembang komunikasi suara menggunakan telepon hingga kini telah sampai pada tahap komunikasi gambar dan video. Dalam proses pentransmisian data baik suara maupun gambar tidak terlepas dari adanya derau. Salah satu solusi dalam menjawab permasalahan tersebut adalah dengan mengembangkan teknologi Filter Digital. Dalam penelitian ini direalisasikan sebuah Filter digital dengan objek gambar menggunakan metode DWMD (Directionan Weighted Minumum Deviation) Filter dengan mendeteksi jenis derau salt and pepper. Metode DWMD Filter adalah metode pengolahan data digital berbasis arah dan standar deviasi yang memperbaiki Median Filter. Dengan membandingkan parameter PSNR maka diketahui bahwa DWMD dapat menghasilkan gambar lebih baik dari Median Filter. Metode Filter DWMD ini ditambah dengan penentuan Threshold otomatis untuk membantu proses filter menjadi lebih cepat dimana diambil selisih PSNR terbesar. Hasil eksperimen menunjukkan bahwa pada level derau 5% - 65% metode DWMD menghasilkan PSNR bernilai 21-36 dB dibandingkan dengan Median Filter sebesar 13-29 dB. Penelitian ini memiliki output berupa aplikasi desktop yang dilengkapi dengan fitur-fitur yang dapat menambahkan derau salt and pepper pada berbagai densitas dan mengakses citra yang dapat diubah ke dalam format grayscale.

Collision is the main issue in safe transportation, including in the railway system. Sensor systems have been developed to detect obstacles to prevent a collision, such as using cameras. One disadvantage of the camera systems is that performance detection decreases in a not clean environment, like the target position behind the fogs. This paper discusses the development of frequency modulated continuous wave (FMCW) radar signal processing for high-speed railway collision avoidance. The development of radar signal processing combines a two-dimensional constant false alarm rate (2D-CFAR) and robust principal component analysis (RPCA) to detect moving targets under clutter. Cell average (CA) and Greatest of CA (GOCA) CFAR are evaluated under a cluttered wall environment along the railway track. From the experiment, the development of FMCW radar can detect stationary or moving obstacles around 675 meters in front of the locomotive. Combining 2D-CFAR and RPCA algorithm outperforms average background subtraction in extracting moving targets from strong clutter signals along the railway track.