This paper presents an effective method for improving the accuracy of
planar scanning for a special moveable near-field Scanner system, which is
use to measure beam patterns in a large antenna array. Using a tracking laser
interferometer, error correction maps are constructed for the X-, Y- and Z-
axes to compensate for the alignment of the scanning plane of a planar
near-field scanner system. The test results confirm that the error correction
map compensation method substantially improves the plane-scanning
accuracy for position alignment and near field measurement results.
The planar accuracy was improved using an error compensation table.
The Z-axis error of the scanned plane without compensated is +0.3 /-0.15
mm and the RMS error is 0.082mm. The Z-axis error with compensation
plane is -0.01/-0.02 mm and the RMS planarity is 0.004 mm. The laser
tracker provides a higher degree of accuracy and saves time on position
alignment.