Next-generation Communications Research CenterPEARL Enters In-Orbit Verification: Ushering in the 6G Era
As 5G becomes increasingly widespread, the blueprint for next-generation 6G communications is coming into focus. The most critical shift is the full integration of Non-Terrestrial Networks (NTN), which overcomes the geographic limits of terrestrial base stations. NTN will enable uninterrupted connectivity in the air, at sea, and in remote regions. The core technology enabling this vision is low-Earth orbit (LEO) satellite communications.
Integrating AI, Sensing Technologies, and Satellite Communications
With the 6G era approaching, the Next-generation Communications Research Center (NCRC) has launched the PEARL Satellite Program. The initiative is designed to conduct proof of concept for LEO communications and lay the groundwork for future development. In addition to collecting space environment data, the program will establish a comprehensive workflow for satellite development and systems engineering.
The PEARL program was initiated in 2021, and after nearly two years of research, development, integration, and testing, it achieved a major milestone with its successful launch in late 2023. While 2023 focused on pre-launch tasks, including system assembly and integration, space environment testing, functional verification, and pre-launch preparations, 2024 shifted toward in-orbit operations, including early orbit control, post-stabilization procedures, and data collection and analysis.
The PEARL program includes two satellites: PEARL-1H and PEARL-1C. The names represent Hon Hai (H) and National Central University (C), respectively. PEARL-1H is equipped with an optical lens developed by Rayprus Technologies Ltd., a Hon Hai subsidiary, and a phased-array antenna from Tron Future Tech. PEARL-1C is equipped with a space environment probe developed by National Central University (NCU).
In 2024, the NCRC team completed the construction of a ground station atop Hon Hai's Neihu building. Equipped with three different types of antennas and connected to indoor servers, the station enables satellite communication, data transmission, and control. It tracks satellite orbits in real time, displays their positions, and schedules communication windows.
Beyond building its own ground station, the team also collaborated with NCU to access additional ground stations. It also leased high-latitude stations in Norway to extend satellite contact time and improve data reception. Apart from receiving beacon signals and monitoring satellite health status, the ground stations also transmit commands to the satellite to retrieve data and images. To date, the satellites have successfully downlinked multiple space images, providing valuable support for ongoing research.
As Taiwan's first broadband communications satellite and the industry's first satellite designed specifically for 6G non-terrestrial network (NTN) experiments, PEARL aims to validate key technologies for the upcoming 6G era, while also investigating how the space environment affects satellite performance and communication quality.
LEO satellites, however, are not meant to replace terrestrial base stations but to serve as a complementary and backup system. In remote mountains, at sea, or in uninhabited regions beyond the reach of ground infrastructure, LEO satellites make seamless connectivity possible.
Tracking Solar Activity to Improve Satellite Performance
In addition to its communications payload, PEARL is equipped with a Compact Ionospheric Probe (CIP) to measure electron density in the ionosphere along the satellite's flight path.
Solar storms can trigger significant fluctuations in ionospheric density, degrading communication quality. They also produce large amounts of ions that heat and expand the atmosphere, increasing air density and atmospheric drag at orbital altitudes, which can cause gradual orbital decay.
In 2024, during peak solar activity, the NCRC team used PEARL's onboard CIP to observe ionospheric changes and cross-check the data against satellite altitude. The team thus gained a deeper insight into how solar activity affects satellite operations and communications.
- 6G
- The sixth generation of mobile communications is expected to emerge around 2030. Compared with 5G, 6G will deliver higher bandwidth, ultra-low latency (<1 ms), and faster data rates of up to 1 Tbps. It will integrate AI, sensing, terrestrial, and communications, enabling immersive applications such as holographic video calls, mixed reality, and smart cities.
Key Technologies for Ushering in the 6G Era
Following its launch in 2023, PEARL faced several challenges in its early orbit operations.
First is attitude instability. Immediately after separation from the rocket, the satellite tumbled rapidly. Engineers used attitude sensors, magnetorquers, and reaction wheels to gradually stabilize its orientation.
Second are the extreme temperature swings. PEARL completes one orbit around Earth every 90 minutes, during which it experiences dramatic temperature shifts of up to 130°C in 45 minutes. These swings tested the resilience of the satellite's structure and components.
Third, imaging calibration. Initial images returned from the satellite were completely black. The team had to send commands from the ground to adjust camera exposure settings until clear images were obtained. In addition, the satellite's attitude sensing and control systems also required calibration via ground commands to ensure proper operation.
Lastly, satellite communications is difficult. Functioning like a mobile base station, PEARL orbits Earth every 90 minutes, with only brief contact windows over Taiwan. Its high velocity causes frequency shifts, a phenomenon known as the Doppler Effect. This is comparable to a radio conversation where one side constantly adjusts channels, making it difficult for the other to maintain clear reception. Engineers overcame this challenge by using predictive models to adjust uplink and downlink frequencies in real time.
After months of effort, these challenges were gradually resolved. Today, PEARL can switch between multiple modes depending on mission requirements: three-axis stabilization mode to maintain a steady attitude, target tracking mode to lock onto communication targets, and sun-tracking mode to adjust its orientation so that sunlight strikes the solar panels perpendicularly to optimize power generation and maximize charging efficiency.
As of May 2024, PEARL has completed its early orbit operations and entered a stable operating phase. Real-time monitoring from the ground station indicates that the satellite's charge-discharge cycles, voltage levels, and power curves are stable and functioning normally.
Satellites Driving the 6G Connectivity Revolution
As we enter the 6G era, NCRC Director Jen-Ming Wu highlights two transformative trends:
First, multi-layered 3D networking. Future 6G infrastructure will no longer be confined to terrestrial base stations; it will incorporate low-Earth-orbit satellites to form a three-dimensional, multi-layered architecture.
Second, the 6G era will offer ubiquitous connectivity. This will address current blind spots in mountainous regions, remote areas, and oceans, enabling seamless connectivity across open spaces and making network access genuinely ubiquitous.
The successful launch and in-orbit validation of PEARL hold strategic importance for Hon Hai's “3+3” transformation strategy. As a core enabling technology, satellite communications will tightly integrate with AI, semiconductors, and other advanced domains to serve as a vital link across platforms.
Looking ahead, the NCRC will continue to use valuable data and operational insights from PEARL's time in orbit as groundwork for the design and planning of next-generation satellites with enhanced functionality and greater system stability. In parallel, the team is pursuing foundational research and software platform development, aiming to establish a complete ecosystem for satellite communications research and validation.
Director Wu emphasized that the goal is to expand satellite capabilities beyond simple point-to-point links into comprehensive service platforms so as to secure a key role for Taiwan in the global LEO satellite supply chain.
As the world moves toward 6G, the PEARL Satellite Program is not only a milestone in Taiwan's LEO satellite journey but also a testament to its innovation, linking academia and industry. From orbital control to signal compensation, space environment sensing to communications validation, PEARL demonstrates the potential of cross-disciplinary collaboration. These accumulated achievements will accelerate the real-world deployment of satellite technologies, paving the way for a ubiquitous, integrated space-terrestrial smart network and positioning Taiwan for leadership in the global 6G landscape.
- Solar Storms
- Solar storms are geomagnetic disturbances caused by high-energy charged particles released by the Sun, such as solar flares and coronal mass ejections. When these particles reach Earth, they interfere with the earth's magnetic fields and affect satellites, navigation systems, and radio communications. They can even cause auroras or disrupt power systems.
| Date | Milestone |
|---|---|
| 2023/11/12 | Satellite launched aboard SpaceX rocket; UHF antenna deployed; first two-way communication established. |
| 2023/11/28 | NORAD tracked its orbital path; PEARL-1H was assigned catalog number 58265. |
| 2023/12/12 | First telemetry data downlinked; system stability and health monitoring initiated. |
| 2023/12/25 | Subsystems calibrated, including UHF, On-Board Computer (OBC), batteries, and solar panels. |
| 2023/12/31 | Tumbling angular velocity measured; attitude sensors and actuators calibrated. |
| 2024/01/11 | Intermittent rapid detumbling maneuvers were executed and validated. |
| 2024/01/25 | Magnetometer deployed; Y-Thomson de-tumbling procedure performed. |
| 2024/02/02 | Magnetometer calibration was conducted; in-orbit performance was verified against models. |
| 2024/03/02 | Reaction wheel testing initiated; three-axis stabilized flight mode confirmed. |
| 2024/03/13 | Solar panels deployed; camera payload uncovered; test imaging conducted. |
| 2024/03/18 | Solar-tracking mode was verified by comparing solar sensor vectors, geomagnetic vectors, and three-axis attitude angles. |
| 2024/04/02 | First six images were downlinked; underexposure and overexposure issues were observed. |
| 2024/04/09 | OBC scheduling functions tested. |
| 2024/04/20 | Ground-target tracking mode validated. |
| 2024/05/15 | Camera exposure parameters adjusted for day/night sides; clearer space images obtained. |
| 2024/06/07 | Cyclical variations in battery temperature, voltage, and current were confirmed across day/night transitions. |
| 2024/07/30 | Battery management reconfigured: aggressive charging in low temperatures; conservative discharging at low voltage. |
| 2024/08/15 | Rooftop dish antenna installation completed at Neihu ground station. |
| 2024/10/22 | NCC experimental R&D telecom license obtained. |
| 2024/11/20 | Antenna pointing and Doppler compensation errors measured; impact on packet transmission in time-varying channels analyzed. |
| 2024/12/25 | GNSS data was cross-checked with orbital propagation; RTC clock drift was confirmed. |