Core Insights - The article discusses the successful development of inter-satellite link technology by the team from National University of Defense Technology, achieving a precision measurement of better than 1.6 nanometers, which is the highest level reported to date [1][8] - This technology is crucial for the next-generation BeiDou satellite navigation system, enabling ultra-precise measurements for inter-satellite communication [1][8] Group 1: Inter-Satellite Link Development - The inter-satellite link is likened to a "highway" connecting satellites, allowing them to communicate and share positions in real-time, thus enabling global service coverage with only domestic ground stations [1][2] - The BeiDou system's third phase aims to establish a global navigation system, overcoming challenges posed by the inability to deploy ground stations globally [1][2] Group 2: Technical Challenges and Solutions - The team faced significant challenges in developing the inter-satellite link, including extreme conditions in space and the need for high precision over vast distances [3][4] - A new approach was adopted to enhance measurement efficiency by extending preprocessing time, which improved sensitivity by 30 times and achieved centimeter-level distance measurement [3][6] Group 3: Precision Orbit Determination - The construction of the inter-satellite link requires precise orbit determination of all satellites, which is a novel challenge without prior successful experiences [4][5] - The team developed a spatial collaborative measurement theory that allows multiple satellites to measure each other simultaneously, enhancing the accuracy of satellite positioning [5][6] Group 4: Ground System Integration - The integration of a ground system with the inter-satellite link is essential for managing the entire satellite constellation, enabling precise orbit determination and time synchronization [7][8] - The team innovated a "direct capture" method to ensure efficient communication between the ground system and satellites, addressing the challenges posed by the dynamic space environment [7][8] Group 5: Future Developments - The breakthrough in inter-satellite link technology is just a small step towards upgrading the next-generation BeiDou system, with plans for continuous evolution and the creation of a new mixed-link mechanism [8] - Future goals include overcoming challenges in intelligent networking technology to enhance the overall capabilities of the navigation system [8]