DS MagBuoy uses active magnetic measurement technology to guide the drilling well connects to the target well or control the relative position drilling. It overcomes the disadvantage of conventional MWD and can directly guide the drill bit to drill through the target point. This system has the advantages of high precision, small size and it can be used in the drill pipe or tubing. The system is consisted of magnetic joint, measuring probe and ground interface box, transmission system and dedicated computer. The typical application is to measure and control the parallel drilling of the wellbore in the SAGD well, and connect the U-shaped well of coalbed methane