inertial guidance system vs inertial navigation system

inertial guidance system and inertial navigation system both are nouns.

Word	Noun	Adjective	Verb	Adverb
inertial guidance system	Yes	No	No	No
inertial navigation system	Yes	No	No	No

As nouns, inertial guidance system and inertial navigation system are synonyms defined as:

inertial guidance system and inertial navigation system: a system to control a plane or spacecraft; uses inertial forces

inertial guidance system (noun)	inertial navigation system (noun)
a system to control a plane or spacecraft; uses inertial forces	a system to control a plane or spacecraft; uses inertial forces