**2.1.2 Navigation sensors**

614 Advances in Wavelet Theory and Their Applications in Engineering, Physics and Technology

Kalman filters to decreasing the random noise. And we need to build the mathematic model of sensors' errors. The MEMS gyroscope has random drift characteristics of weak nonlinear, non-stationary, slow time-varying. And it is sensitive to external environments such as vibration and temperature. The result of Kalman filter is often imprecision and even divergence, because of inaccurate drift error model of MEMS gyroscope. Wavelet transform has the characteristics of multi-resolution and time-frequency localization, and we do not need to build the mathematic model of sensor errors. So it is ideal for signal processing and

However, Synthetic data simulated by means of a computer using real flight data from ServoHeli-20 and ServoHeli-40 RUAV, which is designed and implemented by Shenyang

The following part of this paper is organized as follows. In Section 2, the fault detection approach based on the wavelet transform is established. The RUAV verification platform is introduced in Section 3. The integrated navigation system and the characteristic of inertial sensor are discussed in Section 4. Real RUAV flight fault detection experiments in manual mode are described and discussed in Section 5, and conclusions are given in

During years of research, we have developed two RUAV platforms. The ServoHeli-20 RUAV platform was designed to be a common experimental platform for control and faulttolerant related study before 2009 (Qi, et al., 2006). The hardware components were selected with considerations of weight, availability and performance. After that, we miniaturized the hardware and used 40Kg industry helicopter. And we developed ServoHeli-40 RUAV platform. This RUAV platform can be used for control and navigation algorithm verification

As the basic aircraft of the RUAV system, we chose the small-scaled model helicopter which is available in the market. Such a choice is easy for us to exchange the accessories and reduce

ServoHeli-20 aerial vehicle is a high quality helicopter which is changed by us using a RC model helicopter operating with a remote controller. The modified system allows the payload of more than 5 kilograms, which is sufficient to carry the whole airborne avionics box and the communication units. The fuselage of the helicopter is constructed with sturdy ABS composite body and the main rotor blades are replaced by heavy-duty carbon fibre reinforced ones to accommodate extra payloads. The vehicle is powered by a 90-class glow plug engine which generates 3.0hp at about 15000 rpm, and practical angular rate ranging from 2,000 to 16,000 rpm. The full length of the fuselage is 1260mm and the full width of it is 160mm. The total height of the helicopter is 410mm, the main rotor is 1600mm and the tail rotor is 260mm.

Institute of Automation, have verified the effectiveness of the proposed method.

analysis of MEMS gyroscope.

**2. The RUAV platform** 

and experimental payload platform.

**2.1 ServoHeli-20 platform** 

the cost (Qi, et al., 2010).

**2.1.1 Modified RC helicopter** 

Section 6.

In order to navigate following a desired trajectory while stabilizing the vehicle, the information of helicopter's position, velocity, acceleration, attitude, and the angular rates should be known to the guidance and control system. The ServoHeli-20 RUAV system is equipped with sensors including IMU (Inertial Measure Unit), GPS and digital compass, to obtain above accurate information about the motion of the helicopter in association with environment.


Table 1. Sensors parameters

The picture of sensors in the avionics box is shown in Fig. 1, and their primary parameters are shown in Table I.
