The sampling period is not necessary to be strictly synchronous to that of the signal, the actual sampling is the interval cycle and iterative process, which is close to "ideal synchronous sampling" of measurement accuracy.

Improving accuracy of angle measurement in wind tunnel test , it is very important for improving data accuracy of wind tunnel test .

The adjustment with quasi weights has extensive application in the adjustment of thesame order controI network expanded, which may obtain the same precision datum summaryof the old network and have smaller working conference of adjustment computation than theoverall adjustment.

Results show that the alignment accuracy is obviously improved by the (electro-)optical modulation.

The analyzing results show that LAPLAC operator is better than the others according to placement and alignment accuracies,but the revised SOBEL II operator is the best method of the alignment accuracy,and it has the shortest aligning time and the highest align.

The experiments shows that image registration method based on control point is effective in image registration, and it has higher registration precision.

When these images are fused in pixel-level,they should be registered first and registration precision is required in pixel- level.

just by pressing a button without the sea horizon to turn to,we should know clearly the relationship between the accuracy of zenith distance observed and the accuracy of a position fixed,the causes of the errors of zenith distance observed,what accuracy of zenith distance observed could be obtained and what accuracy standard should be used.

The method for multi-period synchronism of quasi-accuracy is put forward andrealized with single chip computer of MCS - 51 series.