Abstract: In order to improve the positioning accuracy of the geographic coordinate where the center line of long-distance oil and gas pipeline is located, the working principle of the pipeline geographic coordinate measurement system was analyzed, and the error estimation algorithm based on Kalman filter was proposed to compensate the velocity error and odometer error of the navigation system.To lower the error caused by the odometer output signal noise, piecewise linear interpolation method was adopted for data preprocessing to accomplish piecewise trajectory calculation and correction of observation data from inertial navigation system.The simulation test was carried out via a simulation detector equipped with a low-precision inertial navigation system.It is indicated that the trajectory resolved by the strapdown inertial navigation system is consistent with the overall shape and trend of the actual route on test site, and the resolution error is within 1 m.The results show that the error compensation and data preprocessing method based on Kalman filter can effectively filter the step error of mileage under the condition of low-precision measuring devices, and therefore the method is provided with good calculation accuracy and certain application value.