Managing drone air traffic with network services
In our previous post, we examined the possibilities and challenges of radio connectivity for drones. In our research, we are also looking at various services that the network can provide. Our approach is to design our reference architectures by taking the design of the Unmanned Aircraft Systems Traffic Management (UTM) architecture from NASA and the Federal Aviation Administration (FAA) in the US and connecting it to the mobile network services defined by 3GPP.
In this post we will explore a few of the possible services.
Mobile positioning as a supplement to telemetry reports
A prime example of a service the mobile network could provide for drones is the use of the Mobile Positioning System (MPS) for drone traffic management. We can connect the 3GPP location service to the UTM system and provide a rough positioning and tracking capability from the mobile network. The diagram below shows a possible way to connect MPS to UTM.
The use of the MPS system is not meant to replace the GPS positioning and navigation system on the drone itself. GPS will still be used as the primary means of navigation. However, for complex missions, regulation will require that drones provide position information and general telemetry data to the drone traffic management system. Unfortunately, there is no simple and cheap way right now to cross check whether the telemetry information provided by the drone is correct, hence malicious users may report false position information.
The MPS system provides an easy way to cross check the validity of the telemetry data. The MPS system can provide a location estimate with a certain accuracy, such as whether the device is within the radius from between about 30m to 80m, for example. This precision is enough to validate the telemetry data. In addition the MPS positioning information can also be used if the drone fails to report telemetry because of, for example, a malfunction. In this case, MPS positioning information may be used to continue monitoring no-flight zone violations, or even to detect potential crash-landings along with the estimated position of the incident.
Detecting uncertified use of mobile devices
From the mobile network operator perspective, it is important to detect uncertified use of mobile devices and subscriptions. One such use is when a regular mobile phone with a generic broadband subscription is mounted on a drone and is used, for example, for video streaming. This usage, as touched upon in our previous post, may cause significant interference to the network. This means that detecting it is important to trigger mitigation techniques, for instance, to throttle the subscriber’s data communication traffic.
Detection may be done by monitoring radio link characteristics and handover patterns. Once detected, in addition to trigger throttling, the drone traffic management system may be notified too, under the assumption that non-compliant communication equipment use may be linked to non-compliant airspace usage. If a drone flight is not reported to the drone traffic management system, it may pose a hazard to other airspace users. The MPS system can be triggered to monitor the position of the non-compliant drone and eventually a dynamic no-flight zone may be created to alert other drones and aircrafts in the area.
Flight data recorders based on blockchain technology
Another service example is a distributed flight data recorder. When we envision a lot of autonomous drones flying, it will be very important to understand where those drones are and what they are doing. If there is an incident, we should be able to analyze in retrospect what happened, which drones were involved, and in turn who and what was at fault. This capability is not only necessary for law enforcement, but also for insurance companies, manufacturers, and the drone operators themselves.
The flight data recorder that we have developed relies on blockchain technology to ensure data integrity and immutability. Beside operational data, like telemetry or command and control channel characteristics, it can store pre-flight mission requests and approvals exchanged with the drone traffic management system. In case of an incident, we can roll back the mission to find the root cause of the problem. The flight data recorder also allows us to fetch which other drones were in a certain area around a given time. This way interaction or a chain of events involving multiple drones can be traced back. Incidents involving fallen objects can also be tracked back to drones flying over the area and sudden changes in telemetry data, like increasing speed and altitude, can be used to narrow down suspects.
We think that mobile networks will play an important role in realizing the potential of drones. We have investigated whether the current technology using LTE is capable of supporting drones, and we have seen that LTE already today is capable to support drones to a certain scale. We have also identified potential improvements to LTE, as well as 5G capabilities like beam-forming, as suitable for drone applications. All in all, mobile technologies are well equipped to provide connectivity for drones, as mobile networks provide wide-area secure wireless connectivity, utilizing proven technology based on global standards. Hence, drone communication and traffic management solutions relying on this technology will be applicable globally.
Watch our video for an overview and demo.
For further reading:
- Access the slides of our positioning talk at IEEE VTC 2017
- Read about the 3GPP technical study report here: 3GPP TR 36.777, Enhanced LTE support for aerial vehicles
- Read more about the radio network aspects in our recent paper: “The Sky Is Not the Limit: LTE for Unmanned Aerial Vehicles”
- See an invited talk on LTE connected drones at Texas Wireless Summit 2017.
- Read how Ericsson explains performance of drones on LTE networks.