Navigation is simply to determine the position and speed information of the aircraft; Guidance is to regard the aircraft as a particle and control it to fly from one position to another desired position; Control is to regard the aircraft as a rigid body and change its attitude and orbit according to the guidance instructions to achieve the expected value.

Simply put, navigation is to determine the deviation from the expected value; Guidance is a strategy to eliminate deviation; Control is the means to implement strategy.

Of course, the best counterpart after graduation is to go to the Institute of Aeronautics and Astronautics to work on aircraft control. GNC system is one of the most important subsystems of missiles, rockets and satellites. Of course, it is also good for you to find other jobs related to control. Undergraduate students will also take many courses related to control. How much you can learn depends on yourself. I graduated from Xi University of Technology, majoring in detection, guidance and control technology, and engaged in non-aerospace work with many students after graduation. If you want to do research, you should at least graduate from this major.