The need for surveillance data in a UAS & UTM ecosystem

Before you start reading...In the first week of September, another U-space Stakeholder meeting will be organized, this time hosted by the Lithuanian ANSP, Oro Navigacija. The goal of this meeting is, once again, to share lessons learned related to U-space implementation activities. As per tradition, I'm writing an article with my views on a particular topic just before visiting international U-space meetings and/or conferences. So, please check out my previous articles if you haven't seen them yet (e.g., the relationship between C-UAS and UTM, or the impact of SORA) and meet me in Vilnius!

Introduction to Surveillance

This time, I'm highlighting the need for surveillance data in a UAS & UTM ecosystem, but also into the complexity and challenges. In general (in the context of aviation) surveillance refers to the processes and systems used to monitor and track aircraft. It involves the collection, processing, and distribution of (real-time) data regarding the positions, movements, and identification of aircraft. Examples for manned aviation are radar surveillance, ADS-B, and MLAT. For unmanned aviation, we have to think of alternative means to monitor and track UAS. On one hand, this has to deal with the UAS itself (broadcasting their ID, comparable to ADS-B), on the other hand, is related to the systems used to track the UAS (detection).

Why is it needed?

In a UTM ecosystem, real-time data is essential for the safe and efficient integration of all airspace users. However, this also presents certain challenges, which I will address later. Providing traffic information enhances the situational awareness of UAS operators, making operations not only safer but also meeting the requirements for BVLOS (Beyond Visual Line of Sight) operations, as a tactical mitigation measure for air risk in the SORA process. Therefore, I believe it is clear that the added value of such information in the UTM ecosystem is significant.

"For BVLOS operations, the UAS operator is required to demonstrate that it fulfils the TMPRs. U-space does not change this process, however, it provides additional ways and means of fulfilling the requirements for detection. The operator can rely on the U-space Traffic Information Service as a means to detect traffic in the area, so it supports UAS operators in avoiding collisions with manned (and unmanned) traffic." Article: How U-space will impact the SORA.

Another way to approach this is from a security perspective. Detection is crucial in addressing the risks posed by unauthorized drones, which highlights the need for surveillance. I also discussed this in my previous article, The Role of UTM in C-UAS Solutions. It's important to remember that this is not limited to U-space. While U-space may play a critical role in areas with higher risks or larger volumes of drones, it will not (at least in the short term) cover all areas where there is a demand for e.g. security measures or BVLOS operations.

Relation to the U-space framework

Surveillance services are part of the network identification and traffic information services as defined in the U-space regulation (EU 2021/664). These services help identify and monitor UAS flights and distinguish between authorized and unauthorized drones. In summary, the two services:

• The network identification service provides the live flight data of the UAS (e.g. registration number, position etc.). It enables the sharing of information with users via U-space Service Providers (USSPs).
• The traffic information service provides information to UAS operators about other air traffic (both manned and unmanned) that is near the position of their UAS. It therefore supports situational awareness.

The data will be derived from multiple sources to feed the traffic information service. An example has been given in the figure below.

This means that the quality and accuracy of incoming data are critical. Service providers must also ensure that the data is complete, which highlights the importance of electronic conspicuity for both manned and unmanned aircraft, particularly in uncontrolled airspace or areas not designated as U-space airspace (where conspicuity is required). This is essential for creating a comprehensive picture. Also, they must exchange information among other service providers, in the CORUS ConOps (Edition 4) also defined as a separate service called 'Surveillance Data Exchange".

EASA highlights the importance of the performance of traffic information distribution: "USSPs should demonstrate a latency for distributing traffic information that is lower than 5 seconds for at least 99 % of the time." (EU 2021/664)

However, we should not only focus on providing real-time surveillance information. It is also an important source for conducting data analysis, like the (U-space) Airspace Risk Assessment. This means, there is a need for historical data and data analysis. Recently, I showed some work visualizing different sources of information. Check out my post here.

Challenges (a few examples)

Of course, it is easy to say why it is important and how it should work in theory. It also comes with some important challenges which we have to tackle. Just a few examples:

• Line-of-sight. Many traditional surveillance technologies, such as radar systems, are hindered by the line-of-sight requirements that are difficult to achieve in dense urban settings. Buildings and other structures block direct views, making these systems less effective in city environments.

• Multisensor data fusion. In some cases, multiple sensors might track the same object. Merging this data requires algorithms to ensure consistency, filter out duplicates, and resolve any discrepancies between data streams from different systems. This is called multisensor data fusion. Also, data from different sources may arrive at different times, making real-time processing and integration more complex.
• Centralized v.s. decentralized data exchange. The previous challenge of data fusion, for me, also shows the benefits of a centralized architecture. This means a central entity must be responsible for data collection, processing (including fusion) and distribution to relevant entities like USSPs in a U-space ecosystem.

To summarize

So, surveillance is crucial for situational awareness and safety, particularly for BVLOS (Beyond Visual Line of Sight) operations and large-scale UAS operations. U-space provides a traffic information service supporting UAS operators, but the need is not limited to U-space. Especially security, particularly in detecting unauthorized drones, is a crucial reason for having surveillance systems and processes in place; where of course the quality, accuracy, and completeness of the data are crucial!

Let me know in the comments what challenges you see, and if you agree on the importance of surveillance data!