6 Survey at Detailed Design Stage
6.1 General Provisions
6.1.1 The final survey results at the detailed design stage shall satisfy the requirements of design tasks，and the stake locations surveyed and established in the field shall satisfy the requirements of construction setting out.
6.1.2 The survey during detailed design stage consists of several processes，including route selection，route location，survey of stake spacing and elevation difference，plan & section survey，positioning，and check survey.Processes may be combined under uncomplicated conditions.Where GPS is used for direct positioning，the accuracy and reliability requirements on final results shall be satisfied.
6.1.3 During the survey，plans and sections are considered as the major drawings，while subplans of houses，sections of tower foundations and topographic maps of tower locations are considered as the subsection magnified drawings.All data about the same content shall be consistent.The values of tree height reflected in the strip plans shall be consistent with the height line of the trees on the sections.
6.1.4 The elevation error tolerance of a crossing-over point relative to the adjacent straight-line stakes shall not be more than 0.3m，and the elevation error tolerance of a section point or wind slanting point relative to the adjacent straight-line stakes shall not be more than 0.5m.On the plans and sections，the span，stake spacing，and cumulative distance shall be rounded up to 1 meter，and the elevations of straightline stakes and tower location stakes，water level，and crossing-over points shall be rounded up to 0.1m.
6.1.5 For RTK GPS survey，the number of simultaneous observation satellites shall not be less than five，and the permissible deviation of displayed coordinates and elevations shall be less than±30mm.When the displayed offset distance is less than±15mm，the straight-line stakes and tower location stakes may be determined and the actually surveyed data，stake number and instrument height shall be recorded.
6.1.6 The straight-line stakes and tower location stakes within the same line segment should be set out using RTK GPS at the same reference station.If the reference station is changed，the straight-line stakes（or tower location stakes）that are set out using the previous reference station shall be resurveyed.The discrepancy of coordinates between the two surveys shall not be more than 7cm and the elevation discrepancy shall not be more than 10cm.