Development and Performance Analysis of a Tracking Antenna System for Low Earth Orbit Satellite Reception

Low Earth Orbit (LEO) satellites are crucial due to their low altitude ($500-2000 ~\text{km}$) and fast orbital periods, making them suitable for real-time data applications such as weather monitoring. However, their rapid movement poses challenges in maintaining stable signal reception. This research developed an automatic tracking antenna system using a 5-element Yagi antenna, dual-axis stepper motors, and an ATmega328 microcontroller, with Gpredict software calculating real-time satellite positions via Two-Line Element (TLE) data. The antenna movement is synchronized with the satellite trajectory to maintain accurate alignment during each pass. Signal reception was handled by an RTL-SDR dongle, visualized in SDRSharp, and decoded by WXtoImg into weather images. Experimental testing was conducted in Surabaya, Indonesia, targeting NOAA 18 and NOAA 19 satellites at 137.9125 MHz and 137.1000 MHz, respectively. Results showed that signal quality improved significantly at higher elevations; at $\sim 17.9^{\circ}$, the signal-to-noise ratio (SNR) was below 10 dB with poor image quality, while at $\sim 28.1^{\circ}$ and above, SNR reached $\sim 16.7 ~\text{dB}$, producing clear, detailed imagery. The findings demonstrate that the developed system functions effectively for real-time tracking and signal reception of LEO satellites and offers a low-cost, practical solution for academic and amateur satellite imaging purposes.