The invention relates to an inertia measurement unit, which comprises a gyroscope, an accelerometer, a temperature sensor, a GPS (Global Position System), a magnetic field sensor, a pneumatic height gauge, an airspeed pipe, an optical image sensor, a thermal infrared image sensor and a signal processing unit; a signal modulating and converting circuit is connected with output ends of various sensors and used for receiving signals of various sensors; the signal modulating and converting circuit is connected with a calibration and digital processing circuit; the calibration and digital processing circuit is used for processing measurement signals of various sensors and then conveying into an SPI (Serial Peripheral Interface) circuit and a CAN (Controller Area Network) controller; the gyroscope and the accelerometer are connected with a self-detecting circuit and a digital control circuit; the signal modulating and converting circuit is directly connected with the digital control circuit; and the calibration and digital processing circuit is connected with the digital control circuit through an alarm circuit. The inertia measurement unit disclosed by the invention has the advantage of overcoming the inertia measurement precision problem of a micro electromechanical system and is multiple in function, high in precision, low in cost, minimized and high in reliability.