The Optical Wide-field patroL-Network (OWL-Net) is a Korean optical space surveillance system used to track and monitor objects in space. In this study, the characteristics of four Initial Orbit Determination (IOD) methods were analyzed using artificial observational data from Low Earth Orbit satellites, and an appropriate IOD method was selected for use as the initial value of Precise Orbit Determination using OWL-Net data. Various simulations were performed according to the properties of observational data, such as noise level and observational time interval, to confirm the characteristics of the IOD methods. The IOD results produced via the OWL-Net observational data were then compared with Two Line Elements data to verify the accuracy of each IOD method. This paper, thus, suggests the best method for IOD, according to the properties of angles-only data, for use even when the ephemeris of a satellite is unknown.

1. INTRODUCTION
2. PROPERTIES OF ANGLES-ONLY IOD METHODS
3. ANALYSIS OF ANGLES-ONLY IOD TECHNIQUES
    3.1 Characteristics of the IOD Methods according to NoiseLevel of Observation Optical Data
    3.2 Characteristics of the IOD Methods according toObservational Time Interval
4. OWL-NET APPLICATION
    4.1 Cryosat-2
    4.2 KOMPSAT-1
5. SUMMARY AND CONCLUSION
REFERENCES

• Hyewon Hwang(Astrodynamics and Control Lab., Department of Astronomy, Yonsei University)
• Sang-Young Park(Astrodynamics and Control Lab., Department of Astronomy, Yonsei University) Corresponding Author
• Eunji Lee(Astrodynamics and Control Lab., Department of Astronomy, Yonsei University)