Surveillance SDSP – A New Standard for Low Altitude Air Traffic Detections

In the UTM ecosystem, SDSPs (supplemental data service providers) are vital in supplying UAS operators with essential and non-essential data such as air traffic surveillance, aviation weather, Command and Control link coverage, obstacle locations, population density, etc. While some SDSP services require FAA approval, others can be used as informational services only.

But currently, UAS operators must connect to different surveillance data providers to obtain cooperative and non-cooperative intruder detections. Plus, there is no specific service focused primarily on low altitude (below 400 ft AGL) UAS operations.

Co-led by MatrixSpace and INVOLI, ASTM International recently published F3623-23 Standard Specification for Surveillance Supplementary Data Service Providers, establishing benchmark requirements for collecting air traffic surveillance data and disseminating it to users. SDSPs can now develop data fusion capabilities for a single, fused track, eliminating the complexity and providing a “one-stop shop” for surveillance services.

So, what does this mean for the UAS industry?

This standard is intended to be used for UAS operations in Low and Medium Air Risk airspace, and defines minimum performance requirements for Surveillance SDSPs, associated equipment and services, and defines requirements on SDSP users. It also establishes requirements for a service level agreement (SLA) between Surveillance SDSPs and the users of the service. At a minimum SDSPs can provide Detect functionality for the Detect and Avoid (DAA) systems and situational awareness tools to enable Beyond Visual Line Of Sight (BVLOS) UAS operations and support VLOS operations.

According to an SLA, each Surveillance SDSP will define:

• Surveillance and declaration volume sizes (read more information here).
• Applicable limitations and restrictions on aircraft classes and environments,
• Track update rates and accuracy, latency, altitude references, etc.

Users can monitor if the service received from the SDSP is in line with the SLA.

While the essential task of the Surveillance SDSP is to provide intruder Detection, it can also enrich its service offering by providing Alert and Avoid functions for the DAA system users. SDSPs can also support counter-UAS activities by indicating which tracks, if any, are not correlated with cooperative aircraft and which, by their technical characteristics (e.g., Radar Cross Section, velocity, or other attributes), are consistent with being a UAS.

Sensor data providers are depicted on the left and userson the right. The SDSP serves as an intermediary data broker between the two.

Adhering to this new standard, SDSPs can now become pure data brokers – collecting the sensor data and then sending it to users. By subscribing to SDSP services, users eliminate multiple point-to-point connections and onboarding hurdles.

In addition to being a data broker, SDSPs can augment raw data from sensors and provide it to the users (something previously done by the UAS operator themselves) such as track – fusion, coasting, validations, visualizations, etc.

This standard now provides the values for different levels of horizontal and vertical accuracies. For horizontal accuracy, values vary from three to 926 meters and for vertical accuracy, from 15 to 150 meters. Not all the sensors or SDSPs can provide the highest level of track accuracy, so it’s important to introduce tiered accuracy levels with each SDSP, fitting its service into a respective accuracy bin.

Let’s look at a particular example showing the real-life implementation of the Surveillance SDSP.

Company ABC provides SDSP services in Richmond, VA, within a 25-kilometer radius of a city center. The maximum altitude of the air traffic surveillance is 1000 ft AGL, and the minimum is 50 ft AGL.

ABC provides surveillance with a network of ground-based ADS-B In receivers for ADS-B Out intruders and a network of small radars to detect non-cooperative intruders. ABC SDSP offers three levels of service for when an intruder enters the ABC SDSP surveillance volume and is detected both by cooperative and non-cooperative sensor means.

Service One – ADS-B Out intruder enters ABC SDSP surveillance volume

‍ABC SDSP provides just a detection service and, therefore, transmits two tracks to the users ( cooperative and non-cooperative tracks). The users must decide for themselves to determine the exact location of the intruder based on two tracks and if it is a threat to the UAS operations and requires evasive maneuvers.

Service Two – ADS-B Out intruder enters ABC SDSP surveillance volume

‍ABC SDSP provides detection and track fusion services so the user gets one fused track for one intruder versus two different tracks for cooperative and non-cooperative detections. In addition, ABC SDSP provides an alert function and determines if the intruder is a threat to the UAS operations or not.

Service Three – Non-cooperative intruder enters ABC SDSP surveillance volume

‍At the initial detection, the accuracy level is lower as the intruder is detected by only one non-cooperative sensor. As soon as the intruder is detected by two or more sensors, then the track accuracy level goes up and the user can make better decisions about the potential conflict with the intruder.

Conclusion

Sensor providers, such as MatrixSpace, can lead the process of establishing Surveillance SDSP entities as we already have an underlying framework for data provision. Some sensor providers can eventually become Surveillance SDSPs over time while others will simply provide data.

Regardless, this SDSP standard is long overdue and finally simplifies the myriad data sources low altitude operators have had to deal with. It’s an important step in making low altitude flight operations both safe and scalable as we continue to evolve delivery, safety, inspection and transportation services.