Improving the ability to monitor air traffic in a rapidly growing density of aircraft is a necessity complicated by the foreseen increase of Non-Cooperative Targets (NCT). A new monitoring system capable of raising an alert to endangered aircraft or other ground based assets, in case of a confirmed collision risk, is a crucial element to significantly increase aircraft safety and security, especially in the airport Control Terminal Region (CTR) zone. In order to meet these challenges, a new technology has arisen over the past years: the MSPSR (MultiStatic Primary Surveillance Radar).
The SINBAD project was based on passive MSPSR using DVB-T (digital television broadcast) opportunity transmitters. SINBAD stands for Safety and security Improved by New functionality for Better Awareness on airport approach and departure Domain. It was launched under the 6th EU Framework Programme. SINBAD performed the proof of application of a new concept: improvement of aircraft safety and security at airport approach to 2015 horizon.
SINBAD aimed to perform the proof of application of a new concept, intended to improve aircraft safety and security at airport approach to 2015 horizon. Collision avoidance is currently ensured by the Air Traffic Management System (ATMS), and the Airborne Collision Avoidance System. Both systems are actually ineffective against the risk of accidental or hostile collision by non-cooperative small or low flying aircraft.
The main targets of SINBAD to overcome these limitations are:
- to drastically improve the capability of the ATMS to monitor such non-cooperative aircraft, using a breakthrough low cost sensor technology, the MultiStatic PCL (Passive Coherent Location),
- to support controllers by providing them with an Active Hazard Assessment (AHA) capability, allowing them to quickly alert the adequate authorities and if needed to the relevant airliners, in case of confirmed danger .
The scientific objectives of SINBAD are:
- to develop and optimise a mock-up of the MultiStatic PCL sensor on live data, and of the AHA software component,
- to assess MultiStatic PCL improvement in detection and localisation performances compared to currently available sensors,
- to assess AHA's performance in terms of probability to anticipate collision risks between relevant aircraft and airliners, with a controlled false alarm rate.
To achieve this goal, the tasks performed in SINBAD were:
- to refine the air traffic control (ATC) and security management (SMS) operational concepts for those parts that could make use of such enhanced surveillance capabilities;
- to develop a new concept of primary multi-lateration surveillance (PMS);
- to develop a new concept of Active Hazard Assessment (AHA) functionality for the ATC sub system;
- to perform their proof-of-concept at two different sites (Brno and Frankfurt airports).
The objectives NCT classification work in the SINBAD project was to develop software to support the investigations on the feasibility of such a classification, and to establish the background for further relevant research. They were fully achieved.
The Active Hazard Assessment NCTR module used radar echo data from SINBAD's sensor to classify NCTs supplemented with the motion kinematics. The performance data were calculated from 4D flight paths, and a fuzzy logic function was created and tuned with statistics on several types of aircraft (28 including B747, A320, MD90, PZL101, C172, Falcon, Zlin142, Predator, etc.). The belonging probability was given as a membership value by the fuzzy logic. The accuracy of the results was tested in Brno TMA (Terminal Control Area) with radar measurements in the summer of 2010.
The calculated data were reliable; the applied assumptions have an imperceptible influence on results. However while kinematics provides around 80% accuracy in classification, RCS data were insufficient to complement it to an acceptable operational value.
The method needs further relevant development but the NCT classification is achievable with suitable 3D models and with availability of several different bistatic RCS from SINBAD’s sensor independent Tx/Rx pairs. The capacity to classify should be improved by adding more the aircrafts in the database, preferably by measurement but also with additional simulation.
In short SINBAD successfully fulfilled its objectives and a new kind of radar is now ready for product development. In this development phase and beyond the project frame, the following recommendations or extensions should be subject to subsequent research:
- Operational concepts: coverage of CTR or TMA zone or as gap filler for existing PSR. Can one type of product be defined to cover all the identified needs?
- Extension of SINBAD airspace domain associated to data acquisition campaigns, with a particular focus on how deployment and vertical accuracy can be optimized.
- Security monitoring of CT (besides NCT) with additional flight plan conformance monitoring.
- Incorporation of conflict monitoring function in AHA that effectively takes into account NCT intentions and manoeuvrability.
- Incorporation of SINBAD's sensor signal processing for improved NCT classification.
- Safety and Security case development activities to further reduced uncertainties about the concept by confirming the stakeholders' ATM needs, and detailing the expected benefits of the SINBAD concept.
- To perform independent review of the Security case methodology defined within the SINBAD project.
- To systematically rerun additional safety, security and CBA assessment for new airports to take into account the specific conditions in which the SINBAD system is to be operational.
The SINBAD system was composed of one EUROCAT-C testbed connected to the local ATC infrastructure of Brno airport, AHA functions implemented in two PCs, and the passive MSPSR system. This last item was deployed in the countryside for its 4 receivers systems, while the central unit was also at the airport.
Two main test campaigns were conducted at Brno airport. The first one identified several design problems in the sensor, as expected for a research project, and the second one enables the verification of the system performances. With these test campaigns SINBAD's sensor was evaluated, in real time, in terms of sensitivity, covered zone, and accuracy on opportunity aircrafts and dedicated flight.
The air traffic controllers indicated that besides non-cooperative target classification and area infringement monitoring also area escape monitoring, route monitoring and separation monitoring are of interest to them. Area conformance monitoring is of less interest to the controllers, and flow conformance monitoring of no interest to the controllers due to highly flexible routes.
AHA demonstrator has also proven its capacity as a platform for Safety Nets functions verification and validation with a minimal effort in term of design and disturbances of the day to day ATC operations. At the end of the SINBAD project AHA can be easily plug in parallel to an existing ATC system, with or without Safety Nets functions.
To conclude, let's look at the programme overview, the main SINBAD initial objective was to perform the proof of application of a new functionality, Passive Radar for ATC enhanced by an alerter the AHA. It has been successfully completed at prototype level.
In more details Scientific and Technological objectives were:
- S&T1: to refine ATC and security management operational concepts. Achieved by:
- System analysis, live demonstrations and discussion with ATCO.
- Main conclusions are that for ATC, Passive Radar and AHA introduction should be smooth and easy with a Benefit/Costs ratio evaluated at three large airports.
- For security, the subject is newer in the ATC world. As such the consortium had to create the methods of analysis in SINBAD.
- These techniques need now to be tried on other related subjects involving security analysis, both for validation and improvement.
- The results are however outstanding with an estimated Benefits/Costs ratio of greater than ten. This value should be used with care as the security benefits considered are currently not paid for by stakeholders. Given the current trends, where safety improvement and reduction of the costs of PSR coverage leads to an easy business plan, the consortium consider that the security improvements or functions provided by SINBAD shall be difficult to valorised at first.
- Recommendation for a product is to refine the safety cases linked to the management of the small uncooperative aircraft, major aim of the all PSR-like system. Considering that the security cases are for now a side bonus to be investigated in more details once in place. For now even if the security business case has the best ratio the users are not ready to buy full functions.
- S&T2: to develop Primary Multilateration Surveillance (PMS). Achieved as:
- SINBAD has produced a very reliable set of: four receivers, a central unit and a testbed (incorporating EUROCAT-C) all fully operational and field-tested!
- Accuracy performances are at least at the level of current PSR coverage and it is not even a product.
- As such in its demonstrator stage SINBAD's sensor can be deployed and used operationally for low altitude NCT detection and also as a gap filler for PSR.
- Recommendation for a product is to improve the sensitivity of the Rx and deploy more Rxs.
- This prototype is already looking forward at a coastal applic
Apart from the scientific there was also a Potential Impact objective (PI1): to give Europeans a leading position in ATC safety and security management.
- With SINBAD PMS based on DVB-T transmissions the consortium has provided the first operational passive radar capable of PSR level performances and more with its 2D+ capacity.
- SINBAD has initiated methods to handle security requirements and functions that are also a first.
- SINBAD AHA has opened the way for an easy validation assessment of complementary functions to safety nets.
- SINBAD PMS put Europe at the leading edge of passive Radar and MultiStatic Primary Surveillance Radar (MSPSR).
- SINBAD security studies give the lead to Europe on these new analysis methods.
SINBAD was an experimental step used to prove the feasibility of the concept. As an experimental step the developed prototype should not be seen as a fully operational product in terms of robustness, availability or capability to sustain environmental conditions.
In a development phase, beyond the present project frame, the following recommendations or extensions should be subject to subsequent research:
- Extension of SINBAD airspace domain associated to data acquisition campaigns, with a particular focus on how deployment and vertical accuracy can be optimised;
- Security monitoring of Cooperative Target (besides NCT) with additional flight plan conformance monitoring;
- Incorporation of conflict monitoring function in AHA that effectively takes into account NCT intentions and manoeuvrability;
- Incorporation of SINBAD's sensor signal processing for improved NCT classification;
- Transition from standard PSR to MSPSR is still to be defined but with SINBAD the consortium and several interviewed ATM stakeholders consider that the future of PSR functions lies with MSPSR technology.