One or more first formation measurements sensitive to around a sensor string of a drill string deployed in a subsurface formation is received, A 1-D inversion of the first formation measurements is performed at a first reference point. One or more second formation measurements sensitive to ahead of a drill bit of the drill string deployed in the subsurface formation is received. A 1-D inversion of the second formation measurements is performed at a second reference point ahead of the drill bit of the sensor string to determine formation properties ahead of the drill bit, wherein the 1-D inversion of the second formation measurements is based on inversion results associated with the 1-D inversion of the first formation measurements.