"Aero Dana" wrote in message
oups.com...
Not in school, just trying to finally understand this field.

GPS -- is considered radio navigation
But IRS, FMS, and MMR considered just navigation.

Is that a correct way to break it out?

Not really. Simplifying somewhat; GPS, IRS, and MMR are nav sensors. FMS
is a multi-sensor navigator. The sensors feed position data to the FMS.
The FMS tells you how to get from where you are to where you want to be.

Also in terms of flight communications, what is SATCOM? Is that also
through a radio?

SATCOM is SATellite COMmunications. It's a radio that talks thru a
satellite link.

If you're looking for a decent introduction to the field, I recommend the
following book:

Principles of Avionics, Third Edition by Albert Helfrick

It's available from Amazon.com:
http://www.amazon.com/gp/product/188...Fencoding=UTF8

Gerry