The NMEA 0183 standard has been in place since around the 1980’s. Sensors built since then will utilise this protocol through serial interfaces. We read older sentences such as GGA and GLL for GNSS as well as newer sentences such as GNS and INS. We can also connect to and automatically route a multiplexed channel.

Every system is prone to attack. You hear more about Windows attacks because there are far more systems using this operating system as part of a less secure infrastructure. The best defence is corporate IT policy and this is easier to manage if it is a single OS. If you have more than 1 OS on your network then your defence policy has to be more complicated.

No. Collision avoidance is best left to ARPA. This requires use of relative motion which is unnatural on an ECDIS system which should be in true motion.

Radar image overlay is really only useful as a gross error check for the GNSS sensor. On the down-side it clutters the display and requires a special hardware interface to the radar which requires configuration. This is an unnecessary expense with little benefit. We already display the quality indicator of the GNSS sensor in order to check the quality of the position solution and we do overlay the target information from the Radar without the extra screen clutter.