Description

On the 1st of July 2023, the IEEE ComSoc Student Chapter at the University of Peradeniya proudly showcased our team's passion for satellite technology and radio communication during the University of Peradeniya Open Day. The open day of the University of Peradeniya was held to celebrate the 80th anniversary of our university, and it was opened for the entire public in Sri Lanka to come and observe the unseen beauty, technology and equipment in the university. So our audience was more than 1,000 enthusiastic public of Sri Lanka, undergraduates from other universities and professionals who are eager to see the talents of young Pera undergraduates. In collaboration with dedicated undergraduates of the faculty and mentors, we constructed a turnstile antenna optimized for NOAA (National Oceanic and Atmospheric Administration) satellite frequencies (137.100 MHz - 137.9125 MHz) and paired it with a Software-Defined Radio (SDR) setup. This report highlights our successful endeavours in capturing Automatic Picture Transmission (APT) signals from NOAA satellites, such as NOAA 15, NOAA 18, and NOAA 19, and educating attendees about the valuable applications of satellite technology in weather forecasting. Our achievement was made possible through meticulous planning and precise equipment settings. We designed and built a specialized turnstile antenna tailored for NOAA satellite frequencies. We specially selected this Turnstile antenna as it covers a broad area, but the accuracy is quite low compared with other antennas. Although compared with other directional antennas, it is better. Hence, we had to do our experiment outdoors for better accuracy. Also, w e utilized an SDR setup to receive and process signals effectively. Then, we configured a 2.56 MSPS sample rate to ensure high-quality signal capture. Further, we employed wideband FM mode to receive signals from the NOAA satellites. Using the aforementioned equipment and settings, we captured real-time APT signals from NOAA satellites. Notably, during the event, we were able to capture an image from the NOAA 18 satellite. The reception and processing of these APT streams were accomplished with software tools such as SDRSharp and WXtoImg. We considered several factors in choosing the NOAA satellites to execute our experiment. Some of the reasons are, Most NOAA satellites operate in Low Earth Orbit, which is closer to Earth compared to higher orbits. This proximity makes them easier to capture because they pass over ground stations more frequently. NOAA satellites follow predictable orbits, allowing ground stations to schedule passes for data reception. This predictability simplifies tracking and communication. NOAA satellites use specific radio frequencies for data transmission, which are well-documented and known to ground stations. This simplifies the process of tuning antennas and receivers for capture. NOAA has an open data policy, making the data from its satellites freely accessible to the public and various institutions. This encourages a wide range of users to capture and utilize the data. NOAA's satellites provide global coverage, making it possible for ground stations in various locations to capture data, ensuring redundancy and data continuity. NOAA's satellites primarily monitor weather and environmental conditions, which are of significant interest to various organizations and governments. This focus incentivizes investment in ground station infrastructure for data capture. To capture the satellite images, the following procedure was followed. Positioned the antenna in a location with a clear view of the sky, away from obstructions, while ensuring it's correctly tuned for the NOAA satellite frequency range. Connected the receiver (SDR) to the computer via USB or the appropriate interface. Installed the software needed for capturing and decoding NOAA signals on the computer. In the software, set the receiver to the appropriate NOAA satellite frequency. For example, NOAA's polar-orbiting satellites typically transmit on 137.1 MHz. Configured the decoding software to match the satellite passing details for our location. This includes setting the satellite name, elevation, and frequency correction. Started the decoding software and began capturing signals. Details were obtained through the internet. The software processed the captured signals and decoded the satellite imagery and weather data. It produced weather images and data files. The decoded data was saved for analysis, weather forecasting, or educational purposes. One of the primary goals of our participation in the Open Day was to educate attendees about the practical applications of satellite technology, particularly in weather forecasting. We had the opportunity to showcase how satellite imagery can contribute to enhancing weather prediction and monitoring, emphasizing its significance in disaster management and climate studies. We extend our heartfelt gratitude to the following individuals for their unwavering support in making our effort a resounding success: Prof. Aruna Gunawardena, Professor at the Faculty of Engineering, University of Peradeniya, Mr. Tharanga Premathilake, President of the Radio Society Sri Lanka, Mr. Vanodhya Warnasooriya, Former chairperson IEEE Student Branch Chapter, University of Peradeniya. The University of Peradeniya Open Day was an exceptional platform for our team to demonstrate our passion for satellite technology and radio communication. Our successful capture of APT signals from NOAA satellites and the subsequent display of an image from NOAA 18 left a lasting impression on attendees, underscoring the vital role of satellite technology in various fields. Also, we were able to spread the renowned name of Mother Pera to the entire society, showcasing our talents. This event was a remarkable opportunity to inspire interest and awareness about the wonders of space technology and its practical applications, particularly in weather forecasting. We look forward to continued exploration and innovation in the field of satellite technology.