[ARC5] VLF Nav

[D C _Mac_ Macdonald]

Before the US turned off the Selective Availability (SA) function of GPS, multiple US Coast Guard stations along the coasts and also in the Great Lakes regions had LF stations that were capable of providing local augmentation and accuracy to the GPS receivers of that era to correct the errors intentionally introduced by SA. 
 
And I suspect that the USAF still relies more on Inertial Navigation, Astro Trackers, and RADAR for navigation and bombing! 
 
* * * * * * * * * * * 
* 73 - Mac, K2GKK/5 * 
* (Since 30 Nov 53) * 
* Oklahoma City, OK * 
* USAF, Ret (61-81) * 
* * * * * * * * * * * 
 
 
> From: releazer at earthlink.net
> To: arc5 at mailman.qth.net
> Date: Tue, 26 Nov 2013 18:53:53 -0500
> Subject: [ARC5] VLF Nav
> 
> 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