Current status and trends of orbit determination technologies for space gravitational wave detectors

Space-based gravitational-wave detection missions typically deploy three spacecraft in a widely spaced triangular formation in deep-space heliocentric or high Earth orbits. Maintaining high-precision coherence across this distributed, large-scale, and multi-degree-of-freedom system is critical to long-term, stable, and precise detector operations. High-accuracy orbit determination is foundational to mission success. Although a variety of tracking and measurement techniques exist, achievable orbit-determination accuracy is constrained by tracking coverage, systematic measurement errors, formation geometry, orbit-control capability, and the geometry of ground-based tracking networks. This paper presents a systematic overview of orbit-determination requirements for different mission architectures, analyses the performance and technical characteristics of ground-based and space-based tracking methods applicable to spacecraft in heliocentric and geocentric orbits, and discusses current challenges and future directions in high-precision orbit determination technologies to enable reliable, precise operation of space-based gravitational-wave detectors.