Transport wander and earth rotation wander are both types of apparent wander, you need to look at some pictures to understand this.
Have a look
at this page for some pictures
Real wander you get from imperfections in gyros, or from the lat nut, which corrects for apparent wander with real wander.
Finding true north, the INS does not find true north, it aligns itself with true north only if it is north-pointing inertial navigation system. A north-pointing inertial navigation system has a north gyro, this gyro once aligned with true north will tend to remain pointing to true north. As the aircraft moves from its position, the departure is used to align the north gyro with true north (15 Sin lat). The north gyro sends siglnals to the platform gimbal motors that "tilt" the platform in space to keep the platform level with respect to earth but aligned with true north.
There is some feedback via the accelerometors to the gyros if the earth rate, is not calculated accuratly, the accelerometors will sense some acceleration due to gravity and this will be fed back into the azimuth gyro to keep the platform level.
Have to be off...migh re read this later and add to it
