Usage of "that of" or "and that of"

Hi, I was reading paper and I met a structure like "that of/and that of" I don't know. What does it mean? Could you someone who really knows this explain it,please? Thank you.

Some examples;

"As mentioned before, vehicle K calculates the position to vehicle L by differencing its absolute position and that of vehicle L."

or

"This analysis is independent of the proposed method and investigates the potential
achievable performance adopting the approach and that of GPS."

or

"GPS-based position estimate is the difference of the DGPS-based position of the target vehicle and that of its neighbor"