The Netherlands' Defence Materiel Organization and Thales Nederland signed a contract for the delivery of SEASTAR and GATEKEEPER sensors that are to be installed on the two M-class frigates. The modernization will take place in 2011 and 2012 in the scope of the M-frigates' upkeep program. Simultaneously, a contract was signed for the delivery of a GATEKEEPER system that will be installed on the LPD Johan de Witt. The M-Class frigates were introduced in the nineties and were intended for air defence and submarine warfare in the Atlantic. However, these ships are deployed mainly in littoral waters to counter frontier-running, pollution, drugs trafficking and piracy. The SEASTAR and GATEKEEPER sensors provide the vessels with the capability to detect the small targets encountered in such situations. The two new sensors will be matched with the tried-and-true SMART-S surveillance radar and the STIR weapon control radar that are on board of the M-frigates. This contract includes an option for the same modernization of the two M-Frigates that have been purchased by the Belgian Navy in 2005. The Joint Support Ship that will be built for the RNLN is expected to be equipped with an Integrated Mast, similar to the Mast on the OPVs that also includes SEASTAR and GATEKEEPER.