SMART-L (Signaal Multibeam Acquisition Radar for Tracking, L band) is a naval long-range search radar from Thales Nederland, formerly Hollandse Signaalapparaten (Signaal). The passive electronically scanned array antenna has 24 elements; all are used for reception, while 16 are used for creating virtual receiver beams through digital beamforming. The beams' vertical elevation, and compensation for ship movement, is done electronically. Horizontal training is done by mechanically rotating the entire array. As designed, SMART-L has a maximum range of 400 km (220 nmi) against patrol aircraft, and 65 km (35 nmi) against stealthy missiles. A software upgrade, Extended Long Range (ELR) Mode, extends the maximum range to 480 km (260 nmi). In 2006 HNLMS Tromp used the ELR Mode to track an ARAV-B missile from 150 km (81 nmi) during a US Navy ballistic missile defence exercise.