4.4 - Research: UAS in the NAS

Monitoring and maintaining the unmanned aircraft in NAS (National Air Space)

 After its invention, the unmanned aircraft are still struggling to be accepted by the commercial aviation industry due to lack of security, monitoring and maintenance features.    One of the most discussed issues is the separation of the UAS (unmanned aircraft systems) in the national airspace for security reasons (Ramasamy, Sabatini & Gardi, 2014).   Till date, the use of the ADS-B (Automatic Dependent Surveillance-Broadcast) is considered as the most efficient way to monitor the movement of the UAS in certain airspace. This system is developed with the collaborative effort of the NASA and Modern Technology Solutions, Inc. Use of this ADS-B system will enable unmanned aircraft to collect information about the airspace.  The system will analyze the collected data to maintain a safe distance from the other manned or unmanned aircraft in the same airspace.

Considerations need to be made based on variation of sizes and airframes of UAS

 In the case of the smaller UAS group (1&2), this kind of aircraft are able to fly under the line of sight which helps it, operators, to manage its flight path while maintaining safe distance with the other manned or unmanned vehicle (Jeannin et al., 2015).  However, the capacity of these aircraft is less compared to other groups with respect to the integration of the sensory technology for separation.  Hence the ability to avoid the obstacles in the path without operator’s interference is very low.

On the contrary, the higher group (i.e. 3& 5) have better ability and capacity to integrate the sensory system that are important for the separation from the other manned and unmanned aircraft like the ADS-B or ACAS. The mentioned systems are also not error-free, this kind of sensory systems are affected by the latencies which happen due to the control data uplinks of the operator. Again, as the larger unmanned aircraft have increased the operational speed at the high altitudes, therefore this factor reduces their ability separate itself from the other manned or unmanned aircraft.

Different Technologies currently employed by manned aircraft

ACAS (Airborne Collision Avoidance Systems):  This technology is mainly designed to integrate to the manned aircraft for making necessary path adjustment of the flight (Jeannin et al., 2015).  This technology is now under research so that this can be integrated to the UAS that operates in the national airspace of the country.

ASAS (Airborne Separation Assistance Systems):   It is considered as an automatic broadcasting and surveillance system. It helps the unmanned aircraft in the airspace to have situational awareness so that the separation between the unmanned and manned aircraft can be easily done.

Cameras:  In most of the cases it is seen that cameras are integrated with the unmanned aircraft to view and avoid the obstacles, other aircraft by analyzing and processing the captured image by the wide-angle camera. 

TCAS II: One of the widely-used separation technology used for the manned aircraft. The traffic alert and collision avoidance system provides overall safety to the vehicles by providing alert to the pilot of the aircraft in order to avoid the collision with other aircraft in the same airs space (Ramasamy, Sabatini & Gardi, 2014).     

References

Jeannin, J. B., Ghorbal, K., Kouskoulas, Y., Gardner, R., Schmidt, A., Zawadzki, E., & Platzer, A. (2015, April). A formally verified hybrid system for the next-generation airborne collision avoidance system. In International Conference on Tools and Algorithms for the Construction and Analysis of Systems (pp. 21-36). Springer Berlin Heidelberg.

Sahawneh, L. R., Duffield, M. O., Beard, R. W., & McLain, T. W. (2015). Detect and Avoid for Small Unmanned Aircraft Systems Using ADS-B. Air Traffic Control Quarterly, 23(2-3), 203-240.

Ramasamy, S., Sabatini, R., & Gardi, A. (2014, May). Avionics sensor fusion for small size unmanned aircraft sense-and-avoid. In Metrology for Aerospace (MetroAeroSpace), 2014 IEEE (pp. 271-276). IEEE.

Zou, X., Alexander, R., & McDermid, J. (2016, June). On the Validation of a UAV Collision Avoidance System Developed by Model-Based Optimization: Challenges and a Tentative Partial Solution. In Dependable Systems and Networks Workshop, 2016 46th Annual IEEE/IFIP International Conference on (pp. 192-199). IEEE.