Performance Index of a Network of Ground-Based Optical Sensors for Space Objects Observation and Measurements

The total number of space objects in Earth orbits is estimated to be over 200k, while the current number of those that are constantly tracked and cataloged is around 20k. The space traffic is increasing every year, and so the risk of possible collisions, there is a global need to take control of the Low Earth Orbit. The uncertainty associated with the measured position of orbiting objects is one of the main factors impacting performance, accuracy and timeliness. For this reason, aiming for the coordination of a multitude of sensors is one of the most important aspects targeted in the domain. This paper proposes an algorithm to estimate the performance of a globally-distributed network of optical assets (telescope and detector), with off-the-shelf telescope components, deployed in multiple sites distributed across different locations. In the context of space objects detection of size down to 3 cm, the quantitative performance measure is calculated as the portion of total cataloged debris that is visible by the network in a given time window (in our case, 24hrs have been considered). The proposed algorithm takes as input all the NORAD catalog, all the object physical data given by the DISCOS catalog, and all the optical and atmospheric data. It propagates the space object population to obtain their position in the selected time window, filters out all the objects that are not in the ground station network line-of-sight for a sufficient amount of time to guarantee a feasible orbit determination, and on the objects satisfying all previous conditions it estimates the Signal-to-Noise Ratio achievable by the optical assets. The retrieved values are directly converted into a Detection Probability, thus providing a performance index for the given Ground Sensor Network configuration that can be used as an objective function to be optimized when evaluating different architectures.