Aiming at severe environment of high temperature

high impact faced in oil and gas well and smallcaliber

two-position and miniaturized fiber-optic gyroscope（ FOG） inclinometer inertial measurement unit（ IMU） designed by using twinaxial integration FOG and quartz flexible accelerometers as core sensor is realized. Navigation computer scheme uses double CPU structure which consists of a DSC（ dsPIC30F6014A） and a FPGA

which accomplishes navigation calculation and filtering algorithm

and completes data acquisition of IMU

control and transmission. The operation principle and design of IMU

data sampling and interface circuit and dual microprocessor hard structure and software algorithm are introduced in detail. Prototype test results show that the prototype reach expected precision index requirement（ angle of inclination

azimuth and toolface is prior to ± 0. 2°

± 2°

± 0. 5°

respectively）

the system satisfies requirement of performance

size and weight for underground inclinometer design.