Most accupark systems are guided from sensors embedded in the ground or a light system that aligns when properly parked. United had an ingenious system where 2 lights were aligned on the terminal to give nose alignment and 2 were on the speedway to the left for distance. when both were a single light the pilot stopped it never failed. the sensor system worked if the pilot looked at it and was careful. I saw accidents where the crews did not use good judgement upon arrival.
I remember a European 747 crew arriving at SFO
went to the wrong gate and taxied into the jetway after claiming that the sun was blotting out the accupark lights. The Lights were NEVER ON
! So it only works if you're where you're supposed to be and careful about it. These guys hit the jetway with #2 engine before they stopped. The fur flew for 2 weeks after that when they claimed we gave them bad gate information. But the gate they tried to park at wasn't USED
for a 747. It was set up the Aeroflot's IL62 that couldn't use accupark. American and Pan AM
had a parking system years ago that used rails. where the pilot nosed the airplane in until the rail touched the window. I thought that was pretty good too even if low tech. Many of the newer systems do not require a ramper or mechanic to be present except to chock the nose. I still favor the hand held Dead man switch because it requires a second set of eyes on the ground.