Takao Sato, NEC Aerospace Systems, Ltd.; Daisuke Yamashita, NEC Aerosoace Systems, Ltd.; Daiki Mori, NEC Aerosoace Systems, Ltd; Touko Yamada, NEC Aerospace Systems Ltd., Masatoshi Ebara, NEC Corporation; Takahiro Okada, NEC Corporation; Taichiro SANO, NEC Corporation;
Keywords: Application development, Datafusion, SSA
Abstract:
Space systems are now an important infrastructure for our daily life and national security for many countries. There are emerging risks such as the collision with increasing space debris and threats caused by anti-satellite systems etc., which prevent us from using the space environment safely and stably. In order to mitigate these risks, leveraging safety of flight capability with the space situational awareness (SSA) system is effective. NEC has experimentally started SSA operation in Japan for the first time with our unique SSA system, leveraging high definition SSA information which allows us to provide maximum value.
Along with these capabilities, we also find it important to utilize the SSA information to other needs which are more mission oriented such as the GPS information or Earth Observation (EO) images. Through interviews with our potential customers, about leveraging the SSA information, we were able to consider their issues and needs. The most important concern was the dependence on Two-line elements (TLEs) as the orbit information of the space object. We can get TLEs easily, however, they are not enough to complete particular missions which request higher accuracy because of large positon uncertainty and low update frequency. High definition SSA Information would allow us to solve these problems. Especially, the application in the LEO (Low Earth Orbit) region seems to be much in demand. For example, we assume that the information are useful for defense missions, checking the health of a satellite, planning the trajectory for debris removal missions, and Middle-Man service functions like avoidance maneuver recommendations. In this paper, we introduce two studies to investigate how much the difference between TLEs and the high accuracy ephemeris is effective. For some of the studies, we have utilized the original application integrated by System Tool Kit (STK).We are confident that the application which help the analysis of space system operators and the judgment by decision makers will increase in demand.
Study 1 : Access Computation for camouflaging a Specific Target Point
It is important for us to understand the position and attitude of specific space objects passing by specific ground points for some missions. We developed an access computation application to generate the information of the access window and output the countdown time until a target point is accessed by a satellite. As a result, in case of the operation with a potential maneuver performed, we found that we could not ignore the difference between TLEs and high accuracy ephemeris for some missions.
Study 2 : Space Object observation from another Space Object
When the mega constellation satellites come to reality, we might have occasions where we will need to take pictures of anormal space object from other close orbiting satellites for a health check. In this mission, SSA information like TLEs will play an important role as the orbit information. However, we found that there are many situations where this mission will not work with the TLE capability and leveraging high accuracy ephemeris is mandatory for this use case.
In these studies, we focused on only the orbit information of TLEs and high accuracy ephemeris. In future, the advancement of SSA capability enables us to leverage the characterized information of each space objects like sensor FOV to perform an advanced analysis. Application development using these various information is left for our future work.
Date of Conference: September 17-20, 2019
Track: Space Situational Awareness