Michael Hlas

Autonomous navigation and control of unmanned aerial systems in the national airspace

Unmanned aerial vehicles (UAVs) have become smaller and less expensive making them accessible to businesses, law enforcement and the general public. Businesses have proposed ways to use these aircraft for commercial purposes. For unmanned aerial systems to be used on a large scale, an autonomous flight control system needs to be developed. However under current and proposed FAA regulations, all UAVs must be piloted by people to fly in the national airspace. In order for a system like this to be adopted it needs to minimize the amount of changes to the current air traffic control system to reduce costs and air traffic controller training. A system design for this purpose is discussed in this paper.

An autonomous satellite debris avoidance system

Since the launch of Sputnik in 1958, thousands of satellites have been launched by governments and commercial entities for a wide range of purposes. Once a satellite has completed its primary mission, most operators de-orbit or move the satellite into a graveyard orbit as to avoid collisions with active satellites. However, some spacecraft do not have any residual propellant. Other satellites suffer failures and become hazards themselves. Non-operational satellites in orbit have become an increasing collision risk for operational satellites and this problem will only become worse as the number of satellites launched every year increases. Although finding ways to clean up orbital debris is important, near term solutions is needed to mitigate the risk of debris colliding with an active satellite. Traditionally, debris avoidance is performed by operators on the ground who calculate debris conjunctions and analyze the risk of moving the satellite. This paper proposes an alternate solution where the process of analyzing and avoiding orbital debris can be done autonomously by the satellite without human intervention. This provides advantages such as reducing the number of operators needed to maintain a satellite or a large constipation of satellites thus reducing operating costs. With the increased amount of processing power on modern satellites, this system is possible with current technology. The system would first collect a database of two line elements (TLE) for each piece of orbital debris. The satellite will then perform a conjunction analysis against each piece of debris and the satellites predicted future position. The satellite will re-assess these probabilities at set increments as it gets closer to the conjunction, or when the debris database is updated. The satellite operator will be able to set the collision probability threshold. If this threshold is exceeded, the satellite will calculate the most efficient maneuver based off the required delta v, time to the conjunction and staying in its operational orbit. The system will also attempt to combine any required avoidance burns with a normal orbit maintenance burn to minimize fuel consumption. When an appropriate avoidance burn is being considered, the system will check for debris conjunctions in this new orbit. If there is no danger of a collision, the maneuver will be executed.