Longwall Retreat and Creep Measurement Based on UWB Radar Imaging Method

Table 3

Target positions and its errors in the radar coordinate system before and after the advancing, and the advancing displacements according to the target positions in the first simulation.

Targets		Real position (m)	Calculated position (m)	Error (m)
A	Before	(0.786, −2.400, 0.300)	(0.772, −2.418, 0.324)	(−0.014, 0.018, 0.024)
	After	(−0.014, −2.500, 0.300)	(−0.014, −2.506, 0.277)	(0.001, −0.006, −0.023)
	Displacement	(0.800, 0.100, 0.000)	(0.786, 0.088, 0.047)	(−0.014, −0.012, 0.047)
B	Before	(1.386, −2.400, 0.300)	(1.380, −2.401, 0.307)	(−0.005, −0.001, 0.007)
	After	(0.586, −2.500, 0.300)	(0.597, −2.498, 0.376)	(0.012, 0.002, 0.076)
	Displacement	(0.800, 0.100, 0.000)	(0.783, 0.097, −0.069)	(−0.017, −0.003, −0.069)
C	Before	(1.986, −2.400, 0.300)	(2.004, −2.404, 0.369)	(0.018, −0.004, 0.069)
	After	(1.186, −2.500, 0.300)	(1.193, −2.504, 0.271)	(0.007, −0.004, −0.029)
	Displacement	(0.800, 0.100, 0.000)	(0.811, 0.100, 0.098)	(0.011, 0.001, 0.098)