Longwall Retreat and Creep Measurement Based on UWB Radar Imaging Method

Figure 12

The radar imaging results at 0.15 m and 0.30 m heights before and after the robot movement. (a) 0.15 m before the movement, (b) 0.30 m before the movement, (c) 0.15 m after the movement, and (d) 0.30 m after the movement.

(a)

(b)

(c)

(d)