Naval Applications

IFF subsystems for military vessels

Naval air surveillance poses slightly different requirements than land-based ATC. First of all there is the platform, which is not fixed but moving. Another challenge is the limited space that’s available on a ship. Military frigates have a lot of Communication, Navigation and Surveillance (CNS) equipment on-board and all of these compete for the best position on a mast, i.e. the top position.


L-IESA® NR-IFF is the L-band Integrated Electronic Scanning Array, developed for ship-board IFF. It’s a modular, non-rotating IFF system that can be “wrapped-around” a mast of a frigate, as such leaving the top positions available for other CNS systems. L-IESA® NR-IFF incorporates smart beam concepts for electronic levelling of rolling ship movements.

The pinnacle of IFF antenna design

L-IESA® NR-IFF offers unique surveillance capabilities, making it the pinnacle of IFF antenna design

  • unique electronic levelling capabilities
  • counter multipath nulling effects at flat sea
  • interface with any MSSR or STANAG/AIMS certified IFF interrogator
  • supports IFF Mode 1, 2, 3/A, C, S, ADS-B and Mode 5 Level 1 and 2
  • high reliability and maintainability
  • highly integrated antenna system


The Non-Rotating Antenna concept is based on a circular array, rather than the more common multi-faced planar (flat) arrays. This results in less beam degradation when the electronically scanned beam is pointed off the antenna boresight, maintaining near equal performance at all scan angles.

Non-rotating antennas offer numerous advantages over their rotating siblings:

  • lower maintenance costs
  • higher reliability
  • a high degree of integrability

Smart Beam steering

To improve its volume coverage in case of strong ship movements, the L-IESA® NR-IFF is using its unique Vertical Antenna Pointing Diversity (VAPD), an electronic elevation beam steering and leveling. This benefits into improved detection performance, even in case of rough sea.

By implementing in parallel several different switchable elevation antenna diagrams, which are continuously altered, VAPD solves major performance degradation due to multipath, which is very common on legacy ship-born IFF.

Thanks to tis smart beam steering capabilities, L-IESA® NR-IFF offers similar operational modes as its land-based siblings: continuous electronic rotation, confirmation lookbacks, sector scanning.

Stronger together

Intersoft Electronics works with radar manufacturers and integrators to create the surveillance systems of the future. Our mission is to make the skies safer. We do this by providing technological solutions that meet the needs of users. We ensure that all stakeholders, radar users, manufacturers, integrators and society, benefit from the realization of these projects, be it economically, technologically or operationally.

L-IESA NR-IFF on military frigate