After not owning a boat for a number of years I have recently bought a boat with a Navstar (or Navistar) 2000 GPS system. I have a feeling that this model and satellite system is no longer functioning. Is this correct?
Before GPS there was another, simpler, satellite navigation system called Transat I think, and most Navstars were designed to use that. It was turned off about 6 years ago.
But some later Navstar 2000's were adapted to use GPS instead. It sounds like yours may be one.
An additional complication was that in 1997 there was a 'date roll-over' on GPS and some older systems could not cope with this. Also, the electronics in the receiving arial of some early GPS systems seemed prone to fail after a few years. I don't think they liked thunderstorms.