The quantum positioning system (QPS) takes advantage of the entanglement property of the quantum system itself, and it is possible to breakthrough the limitation of the positioning accuracy due to signal bandwidth and power limitation in classical radio-based global positioning system (GPS), and improve the positioning performance. In this paper, a comprehensive survey of the research status of QPS and its several key components are presented, including the quantum entanglement states preparation, the quantum satellite technique, the optical signal acquisition, tracking and pointing (ATP) system, and the quantum positioning and clock synchronization technique. We also discuss the current challenges and future research directions at the end of the paper.
The quantum positioning system (QPS) takes advantage of the entanglement property of the quantum system itself, and it is possible to breakthrough the limitation of the positioning accuracy due to signal bandwidth and power limitation in classical radio-based global positioning system (GPS), and improve the positioning performance. In this paper, a comprehensive survey of the research status of QPS and its several key components are presented, including the quantum entanglement states preparation, the quantum satellite technique, the optical signal acquisition, tracking and pointing (ATP) system, and the quantum positioning and clock synchronization technique. We also discuss the current challenges and future research directions at the end of the paper.
With the continuous improvement of the demand for navigation and positioning services, the accuracy and security of traditional navigation systems have become the limits of future applications.The development of quantum technology has become the hope of a new generation of navigation systems.This paper summarizes and analyzes the research status of quantum active positioning system and passive positioning system and their core technologies, and compares their advantages and disadvantages, and the future development trend of the corresponding technology.Finally, based on the analysis of the problems of quantum navigation system, this paper proposes a solution that may be applied in the future, and puts forward the prospect of the development of quantum navigation system. 1.IntroductionThe position of an object in space can be referred to as its spatial information.Since ancient times, people's daily life has always been closely related to time and space information.We have made great efforts to get our own accurate spatial information.According to statistics, more than 85% of our information is related to time and space.People's demand for positioning and navigation is increasing, and the dependence on location services is becoming stronger.The breadth and depth of application of positioning and navigation are also gradually expanding.In March 2017, the European Navigation Satellite System Authority (GSA) released the GNSS (Global Navigation Satellite System) Market Report, which is expected to cover the global GNSS industry in 2025, including eight application areas such like location services, roads, aviation, maritime, agriculture, where location service and road applications account for more than 90% of the market.It can be seen that people's increasingly strong dependence on positioning and navigation makes the breadth and depth of the application field of positioning and navigation gradually expand.Although the application of GNSS represented by GPS has been widely used, its accuracy and security issues have begun to become prominent in current practical applications.In indoors, underground and cities, canyons and other scenes, GPS cannot provide continuous and accurate services due to occlusion of signals.In addition, radio signals can be eavesdropped or even rewritten, which also causes GPS security to be challenged.Therefore, the main challenge for next-generation navigation technology is high availability and high credibility.In this case, a quantum technology-based navigation system may be the solution.The Quantum Positioning System (QPS) was first proposed in 2001 by Dr. Giovanniti of the Massachusetts Institute of Technology (MIT) in the journal Nature.It is proved by calculation that the quantum entanglement and compression characteristics can further improve the positioning accuracy.By means of the preparation of quantum entangled state and its transmission technology, QPS no longer uses electromagnetic waves, which can not only break through the limits of traditional positioning accuracy, but also provide good protection in terms of confidentiality and anti-
A wide variety of positioning and ranging procedures are based on repeatedly sending electromagnetic pulses through space and measuring their time of arrival. This paper shows that quantum entanglement and squeezing can be employed to overcome the classical power/bandwidth limits on these procedures, enhancing their accuracy by a factor of the square root of the number of pulses employed times the number of photons per pulse. Frequency entangled pulses could be used to construct quantum positioning systems (QPS), to perform clock synchronization, or to do ranging (quantum radar): all of these techniques exhibit a similar enhancement compared with analogous protocols that use classical light.
A quantum positioning system (QPS) is proposed that can provide a user with all four of his space-time coordinates. The user must carry a corner cube reflector, a good clock, and have a two-way classical channel of communication with the origin of the reference frame. Four pairs of entangled photons (biphotons) are sent through four interferometers: three interferometers are used to determine the user's spatial position, and an additional interferometer is used to synchronize the user's clock to coordinate time in the reference frame. The spatial positioning part of the QPS is similar to a classical time-of-arrival (TOA) system, however, a classical TOA system (such as GPS) must have synchronized clocks that keep coordinate time and therefore the clocks must have long-term stability, whereas in the QPS only a photon coincidence counter is needed and the clocks need only have short-term stability. Several scenarios are considered for a QPS: one is a terrestrial system and another is a space-based-system composed of low-Earth orbit (LEO) satellites. Calculations indicate that for a space-based system, neglecting atmospheric effects, a position accuracy below the 1 cm-level is possible for much of the region near the Earth. The QPS may be used as a primary system to define a global 4-dimensional reference frame.
Modern developments have led to a breakthrough in quantum technology that is the key to improving navigation and positioning systems. Translation of concepts such as superposition, entanglement, and quantum interference into quantum sensors pave the way toward high precision and accuracy in measuring gravitational, magnetic, and inertial forces. This chapter provides information on the performance of quantum sensors emphasizing navigation and positioning techniques. The superior performance of quantum accelerometers, gyroscopes, and magnetometers regarding sensitivity, non-drift, and lower errors are compared to classical systems. In addition, the implementation of quantum sensors in systems that can work alone, and in systems that are incorporated with classical GPS systems but have added quantum advantages is explained. This work also discusses the current research and development efforts on quantum sensors, the challenges of integrating them into modern applications, approaches to miniaturizing the technology for practical use, and their potential future adoption in areas such as creature design, autonomous transportation, defense, and aerospace. As a result of the comprehensive content included in this chapter, readers will gain a sufficient appreciation of the scientific principles upon which quantum sensors are anchored, as well as technology’s capability and versatility in enabling accurate navigation and positioning.
Quantum clock synchronization (QCS) aims to establish a shared temporal reference between distant nodes by exploiting uniquely quantum phenomena such as entanglement, single-photon interference, and quantum correlations. In contrast to classical synchronization and time-transfer techniques, which are limited by signal propagation delays, atmospheric disturbances, and oscillator drift, QCS protocols offer the potential to surpass classical precision bounds and enhance resilience against adversarial manipulations. As precise and secure time synchronization underpins distributed quantum networks, navigation systems, and emerging quantum Internet infrastructures, understanding QCS principles, capabilities, and implementation challenges has become increasingly important. This survey provides a unified and critical overview of the rapidly growing QCS research landscape, highlighting fundamentals, protocol types, enabling resources, performance constraints, security considerations, and practical implementations of QCS. We first introduce the theoretical underpinnings of QCS, including entanglement-assisted time transfer, Hong-Ou-Mandel interference-based synchronization, and quantum slow-clock transport. We then categorize the main QCS protocols, ranging from ticking-qubit and entanglement-based schemes to time-of-arrival correlation methods, conveyor-belt synchronization, and quantum-enhanced two-way time transfer. This organization clarifies the relationships between protocol families and their achievable precision advantages over classical methods. Key quantum resources such as spontaneous parametric down-conversion-based entangled photon pairs, Greenberger–Horne–Zeilinger and W multipartite states, squeezed and frequency-entangled light, quantum frequency combs, and quantum memories are reviewed in the context of scalability and robustness. Practical limitations arising from decoherence, channel loss, dispersion, detector timing jitter, and relativistic effects are examined alongside emerging noise mitigation strategies. Security aspects—including eavesdropping on time correlations, intercept-resend attacks, and adversarial delay manipulation—are evaluated with respect to trusted and untrusted network architectures. Recent proof-of-concept demonstrations in fiber networks, free-space optical links, chip-integrated photonic systems, and satellite-ground platforms are summarized, followed by discussions of open challenges toward precise and secure global quantum-synchronized networks.
Quantum clock synchronization (QCS) aims to establish a shared temporal reference between distant nodes by exploiting uniquely quantum phenomena such as entanglement, single-photon interference, and quantum correlations. In contrast to classical synchronization and time-transfer techniques, which are limited by signal propagation delays, atmospheric disturbances, and oscillator drift, QCS protocols offer the potential to surpass classical precision bounds and enhance resilience against adversarial manipulations. As precise and secure time synchronization underpins distributed quantum networks, navigation systems, and emerging quantum Internet infrastructures, understanding QCS principles, capabilities, and implementation challenges has become increasingly important. This survey provides a unified and critical overview of the rapidly growing QCS research landscape, highlighting fundamentals, protocol types, enabling resources, performance constraints, security considerations, and practical implementations of QCS. We first introduce the theoretical underpinnings of QCS, including entanglement-assisted time transfer, Hong-Ou-Mandel interference-based synchronization, and quantum slow-clock transport. We then categorize the main QCS protocols, ranging from ticking-qubit and entanglement-based schemes to time-of-arrival correlation methods, conveyor-belt synchronization, and quantum-enhanced two-way time transfer. This organization clarifies the relationships between protocol families and their achievable precision advantages over classical methods. Key quantum resources such as spontaneous parametric down-conversion-based entangled photon pairs, Greenberger-Horne-Zeilinger and W multipartite states, squeezed and frequency-entangled light, quantum frequency combs, and quantum memories are reviewed in the context of scalability and robustness.