# Telescopic Network of Zhulong for Orbit Determination and Prediction of Space Objects
###### Abstract  
The increasing proliferation of space debris, intermittent space incidents, and the rapid emergence of massive LEO satellite constellations pose significant threats to satellites in orbit. Ground-based optical observations play a crucial role in space surveillance and space situational awareness (SSA). The Zhulong telescopic observation network stands as a pivotal resource in the realm of space object tracking and prediction. This publicly available network plays a critical role in furnishing essential data for accurately delineating and forecasting the orbit of space objects in Earth orbit. Comprising a sophisticated array of hardware components including precise telescopes, optical sensors, and image sensors, the Zhulong network synergistically collaborates to achieve unparalleled levels of precision in tracking and observing space objects. Central to the network's efficacy is its ability to extract positional information, referred to as angular data, from consecutive images. These angular data serve as the cornerstone for precise orbit determination and prediction. In this study, the CPF (Consolidated Prediction Format) orbit serves as the reference standard against which the accuracy of the angular data is evaluated. The findings reveal that the angular data error of the Zhulong network remains consistently below 3 arcseconds, attesting to its remarkable precision. Moreover, through the accumulation of angular data over time, coupled with the utilization of numerical integration and least squares methods, the Zhulong network facilitates highly accurate orbit determination and prediction for space objects. These methodologies leverage the wealth of data collected by the network to extrapolate trajectories with unprecedented accuracy, offering invaluable insights into the behavior and movement of celestial bodies. The results presented herein underscore the immense potential of electric optic telescopes in the realm of space surveillance. By harnessing the capabilities of the Zhulong network, researchers and astronomers can gain deeper insights into the dynamics of space objects, thereby advancing our understanding of the cosmos. Ultimately, the Zhulong telescopic observation network emerges as a pioneering tool in the quest to unravel the mysteries of the universe. space object; telescope; angle measurement; orbit determination; orbit prediction 2024 16282024162282024162282024162282024162282024162228202416  
Earth orbit (LEO) region [3; 4]. The precise orbit determination (OD) and orbit prediction (OP) of space objects have become crucial for collision avoidance, space debris mitigation, and efficient spacecraft operations [5]. Before conducting precise OD and OP of space objects, it is necessary to acquire space object orbit measurement data, which primarily consist of the following:  
1. GNSS (Global Navigation Satellite System) data: The fundamental measurement data collected by the onboard GNSS receiver are the pseudo-range or carrier phase data [6]. Satellite orbit data can be obtained through single-point positioning or relative positioning methods [7]. Depending on the data used and the data processing methods, the orbit's accuracy ranges from tens of meters to millimeters [8; 9]. GNSS measurement data have high accuracy and can be obtained continuously, round the clock [10]. However, only a limited number of space objects can provide GNSS data. 2. Radar observation data: Radar systems utilize electromagnetic waves to transmit and receive reflected waves, enabling the determination of the object's position and motion information [11]. Radar systems possess high accuracy and sensitivity, but their regular operation is typically expensive and not readily available to the public. 3. Telescope angular data: Telescope angular data are obtained by ground or space telescopes through image processing [12].