Interesting replies. However, the original question highlights the somewhat ridiculous situation we are in with exams at the moment. Why on earth do you need to know how a RLG works or how the gyros are connected? If they stop working you will not be able to troubleshoot or fix them! All you really need to know is that you put your start position into an INS and it does the rest. You just have to check from time to time using other navaids that the system is accurate.