Depth Tracking Apparatus (DTA) is a standalone unit that easily connects to Oil and Gas WITS-based drilling systems to provide the information of Real-time measurement of Bit Depth, Rate of Penetration, Weight on Bit, and Slips in/out detection. Receiving data from Rotary Depth Encoder and Hookload sensor, measured depth, WOB and auto slips detection will be transmitted based in WITS protocol. A precise calculation, data monitoring and streaming is the services delivered by this package.