[ARC5] VLF Nav

[Robert Eleazer]

The USN uses VLF Navigation stations - and communications stations as well - because those frequencies penetrate water well and thus the subs do not have to surface to receive the data.

The NDB Station on Cape Canaveral AFS at around 400 KHZ used to broadcast data to augment GPS as well as the Morse signal - and if you drove by it with your car AM radio on, you knew it, too.  But in any case that approach was not adopted.  In Norway they use a subcarrier on FM radio stations to provide GPS data augmentation.   

GPS was designed to help the USAF drop bombs - period - not much need for it to work inside a building.

Wayne