Beyond GPS: How PLA Is Investigating BeiDou Integration for Spatial Dominance

A recent study from the National University of Defense Technology (NUDT), a key PLA institution, highlights the PLA's focus on integrating ground anchor stations and inter-satellite links for the BeiDou system. This research aims to enhance BeiDou's autonomy, precision (PDOP < 1.4), robust command and control (via 3-hop information distribution), and network survivability (connectivity > 3). The ultimate goal is to enable the PLA to conduct resilient precision warfare and maintain critical operations in contested environments, leveraging BeiDou's capabilities for strategic independence and global power projection

In the silence of space, far from public view, a revolution is unfolding that will redefine the future of warfare and global power projection. At the heart of this transformation is China's BeiDou satellite navigation system, which is no longer merely an alternative to the American GPS, but a strategic infrastructure capable of ensuring unprecedented military autonomy and resilience. A recent study, "Integrated assignment of satellite-station/inter-satellite links for the BDS," sheds light on a crucial innovation: the integration of ground anchor stations with the constellation's inter-satellite links (ISL). This move is not just a technical refinement; it is a declaration of intent, a decisive step towards a system that can operate independently and uninterruptedly, even in the most extreme conflict scenarios.

It is important to note that the research in question was published in the latest issue of the scientific journal of the National University of Defense Technology (NUDT). NUDT is the People's Liberation Army's (PLA) premier institution for scientific research and education, directly subordinate to the Central Military Commission. It ranks among China's top universities for computer science, optical engineering, communication engineering, and aerospace sciences. As the only military institution sponsored under the People's Republic of China's major university development programs (the Double First-Class University Plan, Project 985, and Project 211), NUDT is likely the best-funded engineering university in the People's Liberation Army. This context underscores the strategic nature and military importance of such research for China.

Leading the development of launchers and most satellites for China's BeiDou navigation program is the China Aerospace Science and Technology Corporation (CASC). This entity, ranked among the Fortune Global 500, is a vast state-owned enterprise group boasting independent intellectual property rights, renowned brands, exceptional innovative capabilities, and strong core competitiveness. Established in 1956 as the Fifth Academy of the Ministry of National Defense, CASC underwent several historical evolutions before being formally founded on July 1, 1999. Today, CASC comprises 8 large R&D and production complexes, 11 specialized companies, 13 listed companies, and numerous directly affiliated units, with facilities and industrial bases distributed in key cities such as Beijing, Shanghai, Tianjin, Xi'an, Chengdu, Hong Kong, and Shenzhen. Its core business includes the research, design, manufacturing, testing, and launching of space products such as launch vehicles, satellites, manned spacecraft, cargo spacecraft, deep-space explorers, and space stations, as well as strategic and tactical missile systems. Under the military-civilian integration strategy, CASC also focuses heavily on space technology applications in sectors like satellite applications, information technology, new energy and materials, and space biology. It is China's sole satellite operator for broadcasting and communications, and a leading product provider with the broadest scope and strongest technical expertise in China's image recording industry. Currently, CASC is dedicated to transforming China into a space power, steadily advancing major national scientific and technical programs such as manned spaceflight, lunar exploration, BeiDou navigation, and the high-resolution Earth observation system, in addition to new projects like heavy-lift launch vehicles, Mars exploration, asteroid exploration, in-orbit spacecraft servicing and maintenance, and the integrated space-ground information network, which is precisely where this research is situated.

For the People's Liberation Army (PLA), the implications are immense and profoundly practical. Imagine a battlefield where traditional navigation systems have been blinded or spoofed. This is where the integrated BeiDou proves to be a force multiplier. Its ability to maintain millimeter-level precision (with a PDOP below 1.4) means that missiles, drones, and ground units can continue to operate with lethal effectiveness, striking targets with surgical accuracy. But it's not just about targeting. The integrated network ensures connectivity greater than 3, meaning it can withstand the loss of as many as three satellites without losing its integrity. This robustness is vital for operations in contested environments, where anti-satellite (ASAT) attacks or electronic interference are a constant threat.

Furthermore, the research highlights the system's ability to distribute information from anchor stations to satellites in just three "link hops," utilizing less than 10% of time slot resources. This translates into near real-time command and control (C2), enabling the PLA to coordinate forces, update targets, and react swiftly to battlefield developments, even when terrestrial communications are compromised. In essence, BeiDou is evolving from a mere navigation service into a resilient PNT (Positioning, Navigation, and Timing) and communication backbone, essential for modern warfare and China's global power projection, ensuring its armed forces can operate with confidence and strategic independence.

Executive Summary: The Integrated BeiDou System – A Strategic Force Multiplier

The integration of ground anchor stations with BeiDou's inter-satellite link (ISL) network represents a significant leap forward towards a highly autonomous, resilient, and precise Global Navigation Satellite System (GNSS). This architecture fundamentally enhances BeiDou's military utility, offering unprecedented advantages in contested environments where traditional GNSS might be degraded or denied.

The research demonstrates that the integrated network, by introducing ground anchor stations to complement inter-satellite links, solves the problem of purely autonomous constellations lacking time and space references. This architecture achieves optimal information distribution from anchor stations to satellites within 3 hops, ensures superior precision with satellite ranging link Position Dilution of Precision (PDOP) consistently below 1.4, and provides high network robustness with connectivity greater than 3, indicating resilience against the loss of multiple nodes.

These technical advancements directly translate into critical military advantages: they enable resilient precision warfare, enhance Command, Control, Communications, Computers, Intelligence, Surveillance, and Reconnaissance (C4ISR) capabilities, and provide a robust PNT backbone for operations in GPS-denied or contested environments, thereby solidifying China's strategic independence in space.

Introduction: The Geopolitical Imperative of Resilient Satellite Navigation

The Indispensable Role of GNSS in Modern Warfare

Modern military operations are intrinsically linked to precise Positioning, Navigation, and Timing (PNT) data provided by Global Navigation Satellite Systems (GNSS). This encompasses everything from precision-guided munitions (PGMs) and troop movements to intelligence gathering and synchronized communications. The increasing reliance on GNSS, however, creates a critical vulnerability. Any disruption to GNSS services can severely degrade military capabilities, making the development of resilient and autonomous navigation systems a strategic imperative for major powers.

The reliance of modern militaries on GNSS for PNT makes these systems high-value targets in a conflict. Traditional GNSS architectures often depend on extensive and vulnerable ground-based control stations, making them susceptible to attack, jamming, or spoofing. The development of systems like BeiDou's integrated network is a direct response to mitigate these vulnerabilities and ensure the continuity of operational capabilities in contested environments.

The Evolution of BeiDou and the Focus of This Study

BeiDou has rapidly evolved into a global navigation system, challenging GPS's long-standing dominance. This study focuses on a critical advancement: the integration of ground anchor stations with BeiDou's inter-satellite link (ISL) network. The primary objective is to address the challenge of autonomous navigation constellations that, relying solely on inter-satellite links, lack absolute time and space references. BeiDou has introduced ground anchor stations which, together with space satellites, form an integrated satellite-ground/inter-satellite network capable of autonomous operation. This innovative approach aims to improve the system's robustness and precision in complex operational scenarios.

BeiDou's Integrated Architecture: Foundations of Enhanced Capability

Vulnerabilities of Traditional GNSS and BeiDou's Response

Traditional GNSS architectures often rely heavily on a limited number of terrestrial control segments for precise orbit determination, clock synchronization, and command uploads. These ground stations represent potential single points of failure, vulnerable to physical attack, cyberattacks, or electromagnetic interference. Furthermore, a purely space-based constellation relying solely on relative inter-satellite measurements for precise orbit determination and clock synchronization faces a "free network adjustment problem," leading to a lack of absolute inertial space and time references and potential constellation drift. BeiDou's integrated architecture directly addresses these challenges by combining the strengths of inter-satellite links with strategically positioned ground anchor stations.

Inter-Satellite Links (ISL): The Backbone of Autonomy

Inter-satellite links (ISL) form the backbone of communication and measurement within the constellation. They enable direct satellite-to-satellite measurements and data exchange, significantly enhancing the precision of orbit determination and time synchronization across the entire constellation. Beyond PNT, ISLs also provide critical wireless paths for command distribution from the ground control and operations system and for the return of constellation operational data.

The third generation of the BeiDou system utilizes "narrow-beam time-division inter-satellite link technology." This means that each satellite, while equipped with an ISL payload, can establish a link with only one visible node at a time, managing connections with different nodes through time-division multiplexing. This limitation on the number of instantaneous links necessitates sophisticated resource planning. The adoption of "narrow-beam" technology is a critical design decision for military applications. Narrow beams are inherently more difficult for adversaries to intercept, jam, or spoof compared to wide-beam or omnidirectional signals, enhancing the security and integrity of communications within the constellation. The "time-division" aspect, purposing a constraint on simultaneous links, demonstrates an optimized approach to resource management. It allows a single, limited payload to efficiently serve multiple communication and measurement needs sequentially, maximizing the utility of on-board hardware and spectrum. This indicates a system designed for high performance and resilience under constrained operational conditions, which is paramount for military-grade systems.

Ground Anchor Stations: The Inertial Reference Points

Anchor stations are a key innovation introduced by BeiDou to overcome the inherent limitations of a purely space-based autonomous system. Their primary role is to provide the essential "inertial space and time reference" to the constellation. By providing these absolute benchmarks, anchor stations effectively "solve the problem of lacking inertial space and time references" and effectively suppress the "overall constellation rotation," which is the manifestation of the free network adjustment problem.

Conceptually, an anchor station is designed to operate as a "pseudo-satellite" deployed on the ground. Crucially, satellite-ground links established with anchor stations use the same inter-satellite link technology. This unified linking mechanism allows anchor stations to seamlessly integrate with the navigation constellation, forming a true "integrated space-ground network." The concept of a "pseudo-satellite" and the use of unified ISL technology for both space-to-space and space-to-ground links represent a profound architectural choice. Instead of disparate communication systems for ground control and inter-satellite operations, BeiDou creates a homogeneous network where ground anchor stations are effectively treated as additional, fixed nodes within the ISL network. This simplifies network management, reduces potential interoperability issues or vulnerabilities arising from different technologies, and enhances the overall robustness of the system. It means the ground segment is not an external, vulnerable add-on, but an integral, resilient part of the ISL network itself, capable of providing absolute references without introducing new points of failure due to dissimilar technologies.

The Integrated Network: A Unified Ecosystem

The fundamental goal of this integrated architecture is to create an "autonomous satellite-ground/inter-satellite integrated network" that is not only self-sufficient but also highly robust and capable of meeting stringent measurement and communication requirements. The research establishes a comprehensive "integrated assignment" model for link planning. This model employs a multi-objective optimization approach, balancing critical performance metrics such as information distribution efficiency (minimizing link hops), measurement precision (minimizing PDOP), and network connectivity (maximizing robustness against node loss).

Component	Primary Function	Role in Integrated Network
Inter-Satellite Links (ISL)	Satellite-to-satellite measurement and communication; intra-constellation C2; data relay.	Backbone of space-based communication and measurement, reduces reliance on ground.
Ground Anchor Stations	Provide absolute time and space references; information distribution hubs.	Anchor the constellation to a terrestrial inertial reference, acting as "pseudo-satellites."
Integrated Network	Autonomous PNT; robust information distribution; resilient C2.	Combines benefits of ISLs and anchor stations for enhanced autonomy and resilience.

Strategic Advantages Derived from Technical Innovation

Unprecedented Autonomy and Resilience

Anchor stations provide the necessary absolute time and space references, enabling the constellation to operate autonomously without constant reliance on vulnerable terrestrial control stations. This approach solves the "free network adjustment problem" that afflicts purely autonomous systems. The system is inherently designed for "autonomous operation."

True autonomy significantly reduces the vulnerability of traditional GNSS "kill chains." Traditional GNSS systems are often dependent on a limited number of ground control stations for orbit determination, clock synchronization, and command uploads. These ground stations represent single points of failure, vulnerable to physical attack, cyberattacks, or electromagnetic interference. By achieving autonomous operation via ISLs and anchor stations, BeiDou minimizes this dependency. This means that even if critical ground infrastructure is degraded or destroyed, the constellation can continue to provide PNT services, drastically increasing its survivability and operational continuity in a high-intensity conflict. This fundamentally shifts the paradigm of navigation warfare, making it far more difficult for adversaries to deny PNT services.

Superior Precision and Accuracy

Optimized ranging link planning minimizes the maximum PDOP (Position Dilution of Precision) across all satellites. Simulation results show that satellite ranging link PDOP is "less than 1.4 and close to the lower limitation," with anchor station links achieving their reference lower limit. Each satellite maintains a minimum of 10 ranging links.

A PDOP of less than 1.4 is a benchmark for high-precision applications and directly enables advanced military capabilities. PDOP is a geometric factor that amplifies measurement errors into positioning errors. A lower PDOP indicates a better geometric configuration of satellites and thus higher positioning accuracy. A value consistently below 1.4 is considered excellent and is often a requirement for precision-guided munitions (PGMs) and other high-accuracy applications. This directly translates to improved targeting, reduced collateral damage, and increased effectiveness of military strikes. The fact that the system maintains a minimum number of ranging links (≥10) further ensures robust and continuous high-precision data, even if some links are temporarily degraded.

Robust Command and Control (C2) and Information Dissemination

A layered-netWork-based information transfer link assignment algorithm prioritizes rapid data distribution from anchor stations. Anchor stations can distribute information to all satellites within "3 hops," achieving the "theoretical optimal value." This process utilizes less than 10% of time slot resources.

Highly efficient C2 backbone enables real-time operational tempo and strategic responsiveness. In modern warfare, the speed of command and control is paramount. The ability to disseminate critical information (e.g., targeting updates, operational directives, system health checks) across the entire constellation in 3 hops or less, using minimal resources, means BeiDou can support extremely dynamic military operations. This low latency and high efficiency enable rapid adjustments to satellite orbits, clock corrections, or even payload re-tasking in response to the evolving battlefield conditions or threats. This is a direct enabler for agile, responsive, and synchronized military operations, providing a distinct advantage in a fast-paced conflict.

Network Survivability and Anti-Fragility

Multi-objective optimization maximizes "network connectivity," quantifying robustness against node loss. Network connectivity is "better than 3," meaning the network remains connected even with the "unavailability of up to 3 satellites." Some super-frames even achieve connectivity of 5 or 6.

High connectivity provides a critical layer of defense against ASAT attacks, ensuring sustained PNT services. A key vulnerability of space assets is their susceptibility to ASAT attacks. By demonstrating connectivity greater than 3 (and sometimes 5-6), the integrated BeiDou network is explicitly designed to withstand the loss of multiple satellites without disrupting network connectivity. This means that even if an adversary successfully attacks and disables several BeiDou satellites, the remaining network can continue to function and provide PNT services. This anti-fragility is a fundamental military advantage, ensuring mission continuity and reducing the effectiveness of an adversary's counter-space capabilities. It forces an adversary to expend significantly more resources to degrade the system, making such attacks less attractive or effective.

Military Advantage	Technical Basis	Military Value
Enhanced Autonomy	Anchor stations provide absolute references; ISLs enable intra-constellation C2.	Reduced reliance on vulnerable ground segments; continuous PNT in contested environments; increased survivability.
Superior Precision	Optimized PDOP (<1.4); minimum link quantity (≥10).	Enables high-precision targeting for PGMs; improved reconnaissance and mapping; enhanced situational awareness.
Robust C2 & Info Dissemination	Optimal information distribution in 3 hops; low resource utilization (<10%).	Rapid decision-making; real-time targeting updates; synchronized operations; agile constellation management.
Network Survivability & Anti-Fragility	High network connectivity (>3, sometimes 5-6).	Resilient to ASAT attacks; sustained PNT services despite satellite losses; increased cost for adversaries to degrade the system.
Efficient Resource Utilization	<10% of time slots for information distribution; remaining 90% for other optimizations.	High capacity for multi-functional operations; ability to prioritize critical traffic; optimized spectrum and hardware utilization.

Potential Military Applications and Global Strategic Implications

Practical Realization for the PLA: An Integrated PNT and C2 System

The integrated BeiDou architecture, as outlined in the study, is not a mere theoretical speculation but a capability that is materializing with direct and practical implications for the People's Liberation Army (PLA). The BeiDou-3 system has been fully globally operational since July 2020, with a constellation of 30 satellites (24 MEO, 3 GEO, 3 IGSO). These satellites are equipped with inter-satellite link (ISL) payloads, operating in the Ka-band and utilizing time-division multiplexing technology.

On September 19, 2024, China further strengthened the BeiDou system with the launch of two backup satellites (the 59th and 60th BeiDou platform devices) aboard a Long March 3B rocket from the Xichang Satellite Launch Center. These satellites, provided by the Academy of Microsatellite Innovation at the Chinese Academy of Sciences (IAMCAS), were successfully placed into Medium Earth Orbits (MEO) and will serve to maintain the system's full functionality, while also contributing to the development of next-generation BeiDou-4 satellites, with a focus on interference protection and support for underwater, indoor, and deep-space navigation. Retired satellites will be used as backup satellites, allowing for system maintenance and management, and ensuring full functionality.

The practical realization of this integration manifests in several key areas for the PLA:

1. Resilient Precision Warfare:

   • Precision-Guided Munitions (PGMs): The consistently low PDOP of less than 1.4, as demonstrated in the study, directly translates to superior positioning accuracy. BeiDou-3 already offers 10 cm accuracy for encrypted military use. This precision is critical for PGMs, enabling the PLA to strike high-value targets with minimal collateral damage. BeiDou-3's real-time precise point positioning (PPP) capability can achieve sub-meter accuracy (0.4 m horizontal, 2.3 m vertical) and even centimeter-level accuracy (e.g., 6.9 mm horizontal, 4.7 mm east, and 26.6 mm vertical for static PPP) after convergence. This means PLA weapon systems can maintain exceptional targeting even in GPS jamming or spoofing scenarios.

   • Operations in Contested Environments: The network connectivity greater than 3, implying resilience against the loss of at least three satellites, is a vital practical capability. BeiDou was built with China's national security needs in mind and offers better anti-shielding capabilities in low-latitude areas due to a higher number of satellites in high orbits. This allows PLA forces to operate effectively even when adversary GNSS systems are degraded or denied, ensuring continuity of operations for ground, air, and naval forces.

2. Command and Control (C2) and Tactical Communications:

   • Short Message Communication (SMC): BeiDou integrates navigation and communication functions, including short message communication. This "group call" capability enables precise commands and coordination for military use, outperforming GPS in certain military aspects. It allows two-way communication even in areas without mobile network coverage, such as remote regions or oceans. For the PLA, this means commanders can control troop positions at any time and transmit relevant orders.

   • Integration with Weapon Systems and Units: BeiDou is a dual-use technology, primarily intended for military purposes. It enables precision-guided strikes, operations in distant theaters, and the integration of platforms and forces in networked information warfare. PLA units, which previously relied on GPS, are transitioning to BeiDou. BeiDou terminals are already deployed at least to brigade/regiment level for ground forces, on PLAN (People's Liberation Army Navy) ships, the Second Artillery Force, and likely the Air Force (PLAAF). These terminals are regularly used in exercises to augment other communication means and to transmit targeting data to artillery groups. BeiDou is an integral part of the integrated command platform down to at least the brigade/regiment levels.

3. Strategic Autonomy and Power Projection:

   • Independence from GPS: BeiDou's ability to operate autonomously, with reduced reliance on ground control stations, is fundamental to China's national security. The PLA can thus shed its reliance on the U.S. GPS, significantly enhancing its military strength.

   • Military Exercises and Collaborations: The PLA uses BeiDou's high-accuracy PNT services for force movements and precision-guided munitions delivery. China has also entered into agreements for BeiDou use or interoperability with countries like Pakistan, Saudi Arabia, Argentina, and Russia. In late September 2022, Russia and China signed contracts for the reciprocal placement of GLONASS and BeiDou system stations. Russian equipment will be installed in the cities of Changchun, Urumqi, and Shanghai, while Chinese equipment will be placed in Obninsk, Irkutsk, and Petropavlovsk-Kamchatsky. This cooperation, which also includes a space cooperation program for 2018-2022 and a memorandum of understanding on the International Lunar Scientific Station, increases navigation precision and reliability through the simultaneous use of both systems. As early as October 2021, Russia and China had agreed on the integration of GLONASS and BeiDou satellite systems, approving a roadmap for 2021-2025. Iran has announced plans to gradually replace GPS with BeiDou. This international adoption strengthens China's global power projection and influence.

BeiDou in Industry and IT: An Integrated National Ecosystem

In mid-July 2024, the General Administration of China's Ministry of Industry and Information Technology published a document proposing the large-scale introduction of the BeiDou satellite navigation system into industry and IT, with the aim of improving the existing ecosystem in many sectors. This project, implemented to accelerate the large-scale use of BeiDou according to General Secretary Xi Jinping's instructions, focuses on three key areas: mass consumption, industrial production, and global innovation. The initiative envisages the consistent implementation of BeiDou-based applications in the field of mass consumption in various regions of China, with the creation of dynamic control and feedback mechanisms to improve service quality. Authorities intend to stimulate the creation of platforms related to the Internet of Vehicles and smart grids, increasing the share of machines equipped with BeiDou tools. The development of new scenarios for BeiDou application in industrial robotics, aviation, and shipbuilding is encouraged. Furthermore, companies will be able to integrate BeiDou with new technologies such as 5G, high-resolution remote sensing, high-precision vision, and short-range interconnections. This widespread civilian and industrial adoption not only strengthens the Chinese economy but also creates a technological base and familiarity with the system that can be quickly mobilized and adapted for military purposes if needed, further solidifying BeiDou's resilience and strategic independence.

Global Strategic Implications

BeiDou's advancements contribute to a multipolar space environment, challenging GPS's historical dominance. This competition fosters innovation but also introduces complexities into global military and geopolitical dynamics.

Conclusion: Assessing the Future of Navigation Warfare

The research on the integrated assignment of satellite-ground/inter-satellite links for BeiDou reveals a system architecture that sets a new standard for GNSS autonomy, precision, and robustness. Simulation results confirm that anchor stations can distribute information to satellites with a maximum of 3 hops, achieving the theoretical optimal value. The PDOP of satellite ranging links remains below 1.4, approaching its reference lower limit, and the connectivity of the integrated satellite-ground/inter-satellite network exceeds 3. This means the network can maintain connectivity even with the unavailability of up to three satellites.

These technical results directly translate into significant military advantages. BeiDou's ability to operate autonomously, with reduced reliance on ground control segments, enhances its survivability in contested environments. The high precision supports advanced targeting and reconnaissance operations. The rapid and robust dissemination of information enables agile command and control, essential for the tempo of modern military operations. The intrinsic network connectivity provides fundamental resilience against anti-satellite attacks, ensuring the continuity of PNT services even in the event of node losses.

The integrated BeiDou network represents a significant step towards a more resilient and autonomous PNT capability, fundamentally altering the landscape of navigation warfare. It underscores China's commitment to developing independent and robust space infrastructure for national security. This architecture sets a new standard for GNSS resilience and performance, likely influencing future designs of other national navigation systems. Its capabilities will be a critical enabler for China's military modernization and its ability to conduct complex operations in a contested global environment.