Human-Machine Interface; Situational Awareness
Ground Event / Encounter Other / Unknown
General None Reported / Taken
Airport
Taxi to gate from hangar. Taxi into gate with the use of the Auto Park/ DGS (Digital Guidance System). DGS indicated feet to stop point; after it reached 11 ft. it suddenly went to stop and then displayed too far. When departing aircraft observed that nose wheel had gone past the stop point by approximately 3 ft.The guidance system is unreliable and could cause damage/harm to aircraft; personnel; and equipment. Must be out of calibration that it displayed 11 ft. and then suddenly stop / too far. Prior to the 11 ft. the system was indicating count down of feet normally. Calibrate the DGS system on a schedule and inspect for calibration.
Aircraft Technician noted guidance system used to marshal aircraft into the gate is unreliable.