Independent/non-cooperative surveillance is of paramount importance for military ATC operations and Air Defence (AD) operations for which security is the major task.
Civil-military surveillance interoperability
The need for independent and non-cooperative surveillance
From a technical point of view, military ATC surveillance systems are not so different from civil Air Traffic Control (ATC) surveillance systems. A military ATC Primary Surveillance Radar (PSR), for example, is technically the same as a civil ATC PSR. The big difference lies in their operational use.
In some European countries, during peacetime operations, it is mandatory for military controllers to rely on data stemming from independent/non-cooperative surveillance systems such as primary radar. Moreover, surveillance data can be used as an additional means of identification. In such cases, controlling an aircraft with secondary surveillance data alone does not satisfy national military regulations. Non-cooperative aircraft must always be detected for safety and security reasons. As a consequence, independent/non-cooperative surveillance is of paramount importance for military ATC operations and Air Defence (AD) operations for which security is the major task.
Military ATC and AD will continue to use independent non-cooperative surveillance systems, PSR being the only one available today, to carry out their safety and security tasks as decided by their own national governments.
Moving to Multi Static Primary Surveillance Radar technology
The emerging new technology named Multi Static Primary Surveillance Radar (MSPSR), currently being developed by industry, could offer an alternative to such expensive and spectrum inefficient military PSR.
Multi Static Primary Surveillance Radar (MSPSR) is a kind of combination between radar and multilateration. Due to its multi-static design, this technology has the potential to be much more resistant against interference caused by wind turbines. In addition, it could provide Precision Approach Radar (PAR), a service also offering reduced costs through the replacement of very expensive primary radar systems.
However, the main surveillance enabler for the military in the short and medium-term will continue to be PSR. Even in the civil sector, due to ATM security and safety requirements, the importance of PSR as independent/non-cooperative surveillance technology has again been highlighted.
Implementing Mode S
Mode S implementation is progressing and military fleets are progressively being equipped with Mode S capable transponders. Surveillance techniques like ADS-B and Wide Area Multilateration (WAM) are being deployed more and more. The feasibility of fitting ADS-B In/Out in military aircraft was studied within the Single European Sky ATM Research Programme (SESAR) and was proven to be technically feasible with less effort than expected (see in “Related links”, SESAR Project 9.24 ADS-B In/Out for Military Aircraft - Best in Class).
Regulating the Surveillance Performance and Interoperability
To support the implementation of surveillance enablers, the European Commission published the Surveillance Performance and Interoperability Implementing Rule (SPI IR). This regulation includes provisions on airborne equipage such as Mode S Elementary and Enhanced Surveillance, use of Surveillance Identifier (SI) capability, extended squitter and ADS-B Out. The detailed equipage requirements depend on the type of aircraft and are subject to various timeframes, some of them also applicable to State aircraft (see in “Related links”, Surveillance Performance and Interoperability (SPI) mandate and regulation).