Design and experiments of FOG inclinometer for surveying borehole

A fiber optic gyroscope inertial borehole surveyor (FIBS) with independent intellectual property was successfully developed for accurate and efficient borehole survey applications in complex oilfield environments. Compact three-axis fiber optic gyroscopes, quartz flex accelerometers and embedded navigation computer with DSP+FPGA architecture were utilized as core hardware platform. Modern dynamic strapdown computation algorithm and cable aided indirect Kalman Filter error control algorithm were designed for continuous borehole survey operations. Field experimental results show that the inclination error is less than 0.1° and the azimuth error is less than 1°.