US Patent 12086921 Positioning of mobile device in underground worksite

A method is provide, which includes the steps of receiving a three-dimensional tunnel model of an underground tunnel system of a worksite, receiving two-dimensional position data having sets of x coordinate values and y coordinate values of a mobile device in the underground tunnel system, performing a vertical plane ray cast operation in the tunnel model at a mobile device position defined by an x coordinate value and an y coordinate value in the received position data, and determining a z coordinate value for the mobile device position on the basis of the ray cast operation and at least one earlier resolved z coordinate value for a preceding mobile device position.