It shows that the level, like the total station, is classified according to the nominal accuracy, and the I-angle limit of each level is defined.

2, in the grade (GB/T 10 156-2009? ) ",with the following provisions:

The standard deviation and I-angle error of 1KM round-trip leveling with high precision, precision and ordinary leveling are specified respectively.

From the above, the level can be divided into three levels, namely, high-precision level (such as DS05 and DSZ05), precision level (such as DS 1, DSZ 1) and ordinary level (such as DS3 and DSZ3).