Military tech almost always has redundant systems for navigation. The reason why missiles don't prefer GPS or any other radio-based navigation as primary is tha

Military tech almost always has redundant systems for navigation. The reason why missiles don't prefer GPS or any other radio-based navigation as primary is that it is not reliable and not secure enough. An enemy can disrupt or worse alter the signals to re-target the missile. yeah, probably my info is outdated. I am not an expert on military tech.