Research And Application On Error Compensation And Noise Reduction For Current Measuring Circuit

In aircraft, the inertial navigation system needs to get the measured value in high precision of many sensors, such as accelerometer. Those measured value from the sensors is analog signal, such as current and voltage. So it is significant to develop a high-precision current and voltage measurement system suited for aircraft application. Aiming at high precision, this thesis proposes two solutions, which are temperature compensation and noise reduction.In the harsh environment of the inertial navigation system, the temperature is changed frequently, which makes temperature drift error effect the precision badly. Therefore, the temperature compensation becomes a key point. In this thesis, we designed experiments to analyze zero point errors in different temperatures and build a model of the temperature drift error. Based on this model, a software interpolation compensation method was employed.In order to improve the result of temperature compensation, it is necessary to measure temperature of the key electronic components accurately. In this thesis, we improved the configuration and PCB layout design, realized the temperature uniformity around the measuring circuit. Temperature sensors were also used to improve the temperature measurement precision. All these methods were applied in the real measuring current system.There are two kinds of noise sources. One is the natural noise source of measuring circuit. And the other is the interference noise source of environment. In order to reduce the noise, we selected low noise components, used shielding method and improved PCB design properly.The thesis is composed of six chapters as following:Chapter 1: The current status and development of electronic measure technology issummarized. And the object and task of the research on high-precision measuretechnology are put forward according to the request of engineering application.Chapter 2: With the detailed analysis and calculation, the component selection anderror analysis is described in this chapter.Chapter 3: Research and Application on temperature Compensation.Chapter 4: With the detailed analysis and calculation, the component selection andnoise analysis is described in this chapter, and some solution of noise reduction ifpresented.Chapter 5: The design of the current measure system and The capability testexperiments for the mini high-precision data acquisition system are described.Chapter 6: The summary and expectations for the research in the thesis.