A method for improving the performance of centering rod surveying based on two-position correction

To address the problem of a decrease in the measurement accuracy of centering rod surveying as a result of accelerometer bias and scale factor error, a performance improving method for pitch measurement is proposed. The error model of centering rod surveying is built so that the relationship between pitch measurement error and the accelerometer's bias and scale factor error are clear. Numerical simulations are conducted and the error variation is revealed. A two-position correction method is developed and 12 verification experiments are carried out. After correction, the measurement error is reduced from a few centimeters to submillimeter scale. The experimental results illustrate that the accuracy of the pitch measurement is improved effectively, which meets the requirements for use. Three repeated experiments are carried out; the calculated uncertainties are 0.053%, 0.035% and 0.027% separately, which indicates the feasibility and effectiveness of the proposed method in practical applications. This method can provide some guidance for improving the performance of centering rod surveying.