I think you'll need to put one of the antennae on the console somewhere.
I'd put the GPS and VHF either end of the A-frane and AIS on the console. You can use one of the short VTronix Heliflex or Rib Raider type.
See here for details
Although height is always better, AIS or GPS should be OK on the console. You want your prime position for the VHF radio antenna for best possible voice transmiit/receive.
With GPS or AIS, if you lose the odd signal, it's not the end of the world as they will be refrreshed on a frequent basis. If your mayday message is lost, you may not get a second chance!
Because AIS is basically a data transmission, any corruption in the signal will just result in useless information.
Stephen - AIS is 'Automatic Identification System' Has to be installed on all vessels over 300 tonnes and all commercial passenger vessels. It transmits at high end of marine VHF frequencies and giives the ships name, MMSI number, position, speed, course and heading every few seconds. The data it sends is another NMEA sentence set (like GPS). Using something like the NASA AIS Engine, you can decode the data and display it on chartplotters. Not all chartplotters support AIS input though.
Perhaps in the fullness of time we'll see it as an integrated feature on chartplotters with antenna input directly into the unit.