Copter cannot locate postion in Optitrack system

When we put the drone in the origin point (0,0,0) of the optitrack system. The drone have a proper position on MP, but if we put the drone in the other place of the optitrack system ( like -3m, -2m, 0 ), The drone will lost proper position on MP, the phenomenon is like the drone’s position is added with the offset distance (-3m,-2m) of the optitrack system. in addition, the offset distance in MP is enlarged compared with the distance in the optitack system. The drone cannot fly properly with bad position health.