CN1644456A - Miniature assembled gesture measuring system for mini-satellite - Google Patents

Abstract

Translated fromChinese

用于微小卫星的微型组合姿态测量系统，属于微型航天器与航天测控技术领域。为了提高微小卫星在轨姿态测量的实时性、可靠性和抗外界影响能力，本发明提供了用于微小卫星的微型组合姿态测量系统，包括惯性/磁组合测量单元、信号处理电路和存储数据处理程序的星上计算机，惯性/磁组合测量单元是由分别安装在高精度六面基体的三个正交面上的三套基于微机电系统的传感器组组成，每个传感器组均包括微陀螺、微加速度计和微磁强计，各传感器组的输出端均与所述信号处理电路相连，各传感器组的输出信号经信号处理电路处理后，送往星上计算机。本发明可实现完全自主式空间姿态确定和导航，既可不依赖外部信息，又大大克服了纯惯性测量带来的漂移问题。

The invention relates to a micro-combined attitude measurement system for micro-satellites, which belongs to the technical field of micro-spacecraft and aerospace measurement and control. In order to improve the real-time performance, reliability and ability to resist external influences of micro-satellites on-orbit attitude measurement, the invention provides a micro-combined attitude measurement system for micro-satellites, including inertial/magnetic combined measurement unit, signal processing circuit and storage data processing The on-board computer of the program, the inertial/magnetic combined measurement unit is composed of three sets of micro-electro-mechanical system-based sensor groups installed on the three orthogonal surfaces of the high-precision hexahedral substrate, each sensor group includes a micro-gyroscope, For the micro accelerometer and the micro magnetometer, the output ends of each sensor group are connected to the signal processing circuit, and the output signals of each sensor group are processed by the signal processing circuit and then sent to the on-board computer. The invention can realize completely autonomous space attitude determination and navigation, can not rely on external information, and greatly overcomes the drift problem caused by pure inertial measurement.

Description

Translated fromChinese

用于微小卫星的微型组合姿态测量系统Micro-integrated attitude measurement system for micro-satellites

技术领域technical field

本发明属于微型航天器与航天测控技术领域。The invention belongs to the technical field of miniature spacecraft and aerospace measurement and control.

背景技术Background technique

微小卫星是近年来得到迅速发展，它具有重量轻、体积小、成本低、研制周期短、风险小及技术先进等优点，在科学实验、通信、气象、环境检测等方面具有广阔的应用前景，是卫星技术的重要发展方向。作为小卫星技术的重要组成部分，研究开发具有高指向精度和稳定度的姿态测控技术具有十分重要的意义。Microsatellites have been developed rapidly in recent years. They have the advantages of light weight, small size, low cost, short development cycle, low risk, and advanced technology. They have broad application prospects in scientific experiments, communications, meteorology, and environmental testing. It is an important development direction of satellite technology. As an important part of small satellite technology, it is of great significance to research and develop attitude measurement and control technology with high pointing accuracy and stability.

目前微小卫星的姿态测量系统主要使用的传感器包括太阳敏感器、星敏感器、红外地球敏感器、磁敏感器等，其中，太阳敏感器、磁敏感器和红外地球敏感器的精度相对有限，星敏感器的精度较高。但是，它们工作中响应时间相对较长，且存在视场等问题。同时，他们都容易收到外界的影响，因此在卫星变轨等机动过程中可能出现短期失效。另外，目前用于轨道控制的GPS等技术更加依赖导航星等外界信息，也就更容易收到影响。因此，研究具有更好性能的微小卫星自主导航技术具有重要意义。这种系统不仅应能不依赖于地面系统的自主运行，还应具有良好的抗外界影响的能力和实时性。另外，目前卫星的发展趋向微小型化，也日益要求采用小型化、廉价和满足任务要求的自主导航系统。At present, the attitude measurement system of micro-satellites mainly uses sensors including sun sensors, star sensors, infrared earth sensors, and magnetic sensors. The accuracy of the sensor is high. However, they work with relatively long response times and issues such as field of view. At the same time, they are all susceptible to external influences, so short-term failures may occur during maneuvers such as satellite orbit changes. In addition, GPS and other technologies currently used for orbit control rely more on external information such as navigation stars, so they are more likely to be affected. Therefore, it is of great significance to study the autonomous navigation technology of micro-satellites with better performance. This kind of system should not only be able to operate autonomously without relying on the ground system, but also have a good ability to resist external influences and real-time performance. In addition, the current development of satellites tends to be miniaturized, and it is increasingly required to adopt an autonomous navigation system that is miniaturized, cheap, and meets mission requirements.

发明内容Contents of the invention

为了提高微小卫星在轨姿态测量的实时性、可靠性和抗外界影响能力，本发明提供了一种用于微小卫星的微型组合姿态测量系统，其特征在于：所述微型组合姿态测量系统包括惯性/磁组合测量单元、信号处理电路和存储数据处理程序的星上计算机，所述惯性/磁组合测量单元是由分别安装在高精度六面基体的三个正交面上的三套基于微机电系统的传感器组组成，每个传感器组均包括微陀螺、微加速度计和微磁强计，所述各传感器组的输出端均与所述信号处理电路相连，各传感器组的输出信号经信号处理电路处理后，送往星上计算机，并由存储在星上计算机中的数据处理程序执行以下步骤：In order to improve the real-time performance, reliability and ability to resist external influences of micro-satellites on-orbit attitude measurement, the present invention provides a micro-combined attitude measurement system for micro-satellites, which is characterized in that: the micro-combined attitude measurement system includes inertial /magnetic combination measurement unit, signal processing circuit and on-board computer storing data processing program, the inertial/magnetic combination measurement unit is composed of three sets of micro-electromechanical The system consists of sensor groups, each sensor group includes a micro-gyroscope, a micro-accelerometer and a micro-magnetometer, the output terminals of each sensor group are connected to the signal processing circuit, and the output signals of each sensor group are processed by signal processing. After the circuit is processed, it is sent to the on-board computer, and the data processing program stored in the on-board computer performs the following steps:

定义误差四元数为由姿态估计值向真实值转动所需的四元数，首先利用测得的微小卫星三轴角速度和线加速度，通过所述的误差四元数构建状态向量和误差向量，进而得到系统状态方程；同时，通过实时获得的磁场强度在星体坐标系下的三轴分量构建测量方程，然后，利用所述的系统状态方程和测量方程，将微陀螺、微加速度计与微磁强计测得的数据输入扩展卡尔曼滤波器，进行所述微型组合姿态测量系统的姿态估计，获得微小卫星的实时姿态信息。Define the error quaternion as the quaternion required to rotate from the attitude estimation value to the real value. First, use the measured three-axis angular velocity and linear acceleration of the microsatellite to construct the state vector and error vector through the error quaternion, Then the system state equation is obtained; at the same time, the measurement equation is constructed by the three-axis component of the magnetic field strength obtained in real time in the astral coordinate system, and then, using the described system state equation and measurement equation, the micro gyroscope, micro accelerometer and micro magnetic The data measured by the strong meter is input into the extended Kalman filter, and the attitude estimation of the micro-combined attitude measurement system is performed to obtain the real-time attitude information of the micro-satellite.

在本发明中，所述信号处理电路集成于高精度六面基体的底部，包括滤波电路、信号放大电路、A/D转换电路及串行接口，依次完成信号滤波、放大和A/D转换，并将经处理后的微陀螺、微加速度计和微磁强计输出信号统一转换到-5V～+5V范围，信号处理电路中的串行接口通过固定在所述基体上的航天接插件与所述星上计算机连接。In the present invention, the signal processing circuit is integrated at the bottom of the high-precision hexahedral substrate, including a filter circuit, a signal amplification circuit, an A/D conversion circuit and a serial interface, and sequentially completes signal filtering, amplification and A/D conversion, and the processed output signals of the micro-gyroscope, micro-accelerometer and micro-magnetometer are uniformly converted to the range of -5V ~ +5V, and the serial interface in the signal processing circuit communicates with all The computer on the star is connected.

本发明的优点在于：The advantages of the present invention are:

1)将惯性技术用于微小卫星的姿态确定，并将其与微磁强计相结合，通过设计的组合定姿的数据处理方法，实现了二者相结合的微型组合姿态测量系统。该系统可实现完全自主式空间姿态确定和导航，既可不依赖外部信息，又大大克服了纯惯性测量带来的漂移问题。1) The inertial technology is used to determine the attitude of the micro-satellite, and it is combined with the micro-magnetometer. Through the data processing method of the combined attitude determination, a micro-combined attitude measurement system combining the two is realized. The system can realize completely autonomous space attitude determination and navigation, which can not only rely on external information, but also greatly overcome the drift problem caused by pure inertial measurement.

2)利用微型组合姿态测量系统进行微小卫星姿态的确定，有效提高了姿态测量精度，降低了姿控系统的体积、重量和成本。2) Using the micro-combined attitude measurement system to determine the attitude of the micro-satellite effectively improves the attitude measurement accuracy and reduces the volume, weight and cost of the attitude control system.

3)本发明的设计为实现基于MEMS的整体化卫星姿态测量系统打下了基础。3) The design of the present invention has laid the foundation for realizing the integrated satellite attitude measurement system based on MEMS.

附图说明Description of drawings

图1是用于微小卫星的微型组合姿态测量系统的结构框图。Figure 1 is a structural block diagram of a micro-combined attitude measurement system for micro-satellites.

图2是惯性/磁组合测量单元的原理结构示意图。Fig. 2 is a schematic diagram of the principle structure of the inertial/magnetic combined measurement unit.

图3是微型组合姿态测量系统的数据处理流程图。Figure 3 is a flow chart of data processing of the micro-combined attitude measurement system.

图4是微型组合姿态测量系统的输出校正组合方式原理图。Fig. 4 is a schematic diagram of the output correction combination mode of the micro-combined attitude measurement system.

图5是微型组合姿态测量系统的反馈校正组合方式原理图。Fig. 5 is a schematic diagram of the combination mode of feedback correction of the micro-combined attitude measurement system.

具体实施方式Detailed ways

下面结合附图来进一步说明本发明。The present invention will be further described below in conjunction with the accompanying drawings.

如图1所示，本发明提供了一种用于微小卫星的微型组合姿态测量系统，包括惯性/磁组合测量单元、信号处理电路和存储数据处理程序的星上计算机，其中，惯性/磁组合测量单元的结构如图2所示，由分别安装在高精度六面基体的三个正交面上的三套基于微机电系统的传感器组组成，每个传感器组均包括微陀螺1、微加速度计2和微磁强计3。所述各传感器输出的信号均为模拟电压信号，分别对应星体当时绕三个正交轴的角速度、沿三个正交方向的线加速度和磁场强度。三套传感器组的信号线(共9路)通过各自的接插件连接到信号处理电路4上。信号处理电路集成于高精度六面基体的底部，包括滤波电路、信号放大电路、A/D转换电路及串行接口，依次完成信号滤波、放大和A/D转换，并将经处理后的微陀螺、微加速度计和微磁强计输出信号统一转换到-5V～+5V范围，信号处理电路中的串行接口通过固定在所述基体上的航天接插件5与所述星上计算机连接。As shown in Fig. 1, the present invention provides a kind of micro-combined attitude measurement system for micro-satellites, comprising an inertial/magnetic combination measurement unit, a signal processing circuit and an on-board computer storing a data processing program, wherein the inertial/magnetic combination The structure of the measurement unit is shown in Figure 2. It consists of three sets of MEMS-based sensor groups installed on three orthogonal surfaces of a high-precision hexahedral substrate. Each sensor group includes a micro-gyro 1, a micro-acceleration Gauge 2 andMicromagnetometer 3. The signals output by each of the sensors are analog voltage signals, respectively corresponding to the angular velocity of the star around the three orthogonal axes, the linear acceleration along the three orthogonal directions, and the magnetic field strength. The signal wires (9 routes in total) of the three sets of sensor groups are connected to thesignal processing circuit 4 through respective connectors. The signal processing circuit is integrated on the bottom of the high-precision hexahedral substrate, including filter circuit, signal amplification circuit, A/D conversion circuit and serial interface, and completes signal filtering, amplification and A/D conversion in sequence, and the processed micro The output signals of the gyroscope, the micro-accelerometer and the micro-magnetometer are uniformly converted to the range of -5V～+5V, and the serial interface in the signal processing circuit is connected with the on-board computer through theaerospace connector 5 fixed on the substrate.

从数据处理上来看，本系统可采用两种组合方式，即输出校正组合方式和反馈校正组合方式，基本原理如图4、图5所示。在输出校正组合方式中，滤波的结果直接与微型惯性测量组合(MIMU，包括上述的3个微陀螺和3个微加速度计)输出相结合，补偿输出误差，而不影响系统的工作状态，但由于不采用反馈，对滤波器模型误差较敏感，所以要求使用较精确的模型。而反馈校正组合方式先利用滤波器估算出误差，然后反馈校正MIMU。From the point of view of data processing, this system can adopt two combination methods, that is, the output correction combination method and the feedback correction combination method. The basic principles are shown in Figure 4 and Figure 5. In the output correction combination mode, the filtered result is directly combined with the output of the MIMU (including the above-mentioned 3 micro-gyroscopes and 3 micro-accelerometers) to compensate the output error without affecting the working state of the system, but Since no feedback is used, it is more sensitive to the error of the filter model, so a more accurate model is required. The feedback correction combination method first uses the filter to estimate the error, and then feeds back and corrects the MIMU.

针对微小卫星的特点，以上经信号处理电路处理的传感器输出信号在星上计算机内完成解算，详细过程如下：According to the characteristics of micro-satellites, the above sensor output signals processed by the signal processing circuit are solved in the on-board computer. The detailed process is as follows:

首先，根据卫星姿态运动学模型和三轴磁强计测量模型得出组合系统的姿态数学模型：First, the attitude mathematical model of the combined system is obtained according to the satellite attitude kinematics model and the three-axis magnetometer measurement model:

1)运动学模型1) Kinematics model

$\stackrel{<span><span>\&CenterDot;</span>\&CenterDot;</span>}{\mathrm{<span><span>Q</span>Q</span>}}<span><span>=</span>=</span>\frac{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>2</span>2</span>}}{\stackrel{<span><span>~</span>~</span>}{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}}_{\mathrm{<span><span>bi</span>bi</span>}}<span><span>\&CircleTimes;</span>\&CircleTimes;</span>\mathrm{<span><span>Q</span>Q</span>}$

$\left[\begin{array}{c}{\stackrel{<span><span>\&CenterDot;</span>\&Center\; Dot;</span>}{\mathrm{<span><span>q</span>q</span>}}}_{\mathrm{<span><span>1</span>1</span>}}\\ {\stackrel{<span><span>\&CenterDot;</span>\&CenterDot;</span>}{\mathrm{<span><span>q</span>q</span>}}}_{\mathrm{<span><span>1</span>1</span>}}\\ {\stackrel{<span><span>\&CenterDot;</span>\&Center\; Dot;</span>}{\mathrm{<span><span>q</span>q</span>}}}_{\mathrm{<span><span>1</span>1</span>}}\\ {\stackrel{<span><span>\&CenterDot;</span>\&CenterDot;</span>}{\mathrm{<span><span>q</span>q</span>}}}_{\mathrm{<span><span>1</span>1</span>}}\end{array}\right]<span><span>=</span>=</span>\left[\begin{array}{cccc}\mathrm{<span><span>0</span>0</span>}& {\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>biz</span>biz</span>}}& {<span><span>-</span>-</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>biy</span>biy</span>}}& {\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>bix</span>bix</span>}}\\ <span><span>-</span>-</span>{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>biz</span>biz</span>}}& \mathrm{<span><span>0</span>0</span>}& {\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>bix</span>bix</span>}}& {\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>biy</span>biy</span>}}\\ {\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>biy</span>biy</span>}}& <span><span>-</span>-</span>{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>bix</span>bix</span>}}& \mathrm{<span><span>0</span>0</span>}& {\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>bix</span>bix</span>}}\\ <span><span>-</span>-</span>{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>bix</span>bix</span>}}& <span><span>-</span>-</span>{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>biy</span>biy</span>}}& {<span><span>-</span>-</span>\mathrm{<span><span>\&omega;</span>\&omega;</span>}}_{\mathrm{<span><span>bix</span>bix</span>}}& \mathrm{<span><span>0</span>0</span>}\end{array}\right]<span><span>\&CenterDot;</span>\&Center\; Dot;</span>\left[\begin{array}{c}{\mathrm{<span><span>q</span>q</span>}}_{\mathrm{<span><span>1</span>1</span>}}\\ {\mathrm{<span><span>q</span>q</span>}}_{\mathrm{<span><span>2</span>2</span>}}\\ {\mathrm{<span><span>q</span>q</span>}}_{\mathrm{<span><span>3</span>3</span>}}\\ {\mathrm{<span><span>q</span>q</span>}}_{\mathrm{<span><span>4</span>4</span>}}\end{array}\right]<span><span>-</span>-</span><span><span>-</span>-</span><span><span>-</span>-</span><span><span>(</span>(</span>\mathrm{<span><span>1</span>1</span>}<span><span>)</span>)</span>$

式中Q＝[q₁ q₂ q₃ q₄]^T为从惯性坐标系到载体坐标系的姿态四元数，${\widetilde{\mathrm{\&omega;}}}_{\mathrm{bi}}={\left[\begin{array}{ccc}{\mathrm{\&omega;}}_{\mathrm{bix}}& {\mathrm{\&omega;}}_{\mathrm{biy}}& {\mathrm{\&omega;}}_{\mathrm{biz}}\end{array}\right]}^T$为载体相对于惯性坐标系的角速率。In the formula, Q=[q₁ q₂ q₃ q₄ ]^T is the attitude quaternion from the inertial coordinate system to the carrier coordinate system,${\widetilde{\mathrm{\&omega;}}}_{\mathrm{bi}}={\left[\begin{array}{ccc}{\mathrm{\&omega;}}_{\mathrm{bix}}& {\mathrm{\&omega;}}_{\mathrm{biy}}& {\mathrm{\&omega;}}_{\mathrm{biz}}\end{array}\right]}^T$ is the angular velocity of the carrier relative to the inertial coordinate system.

2)微陀螺输出模型2) Micro gyroscope output model

ω_bi＝u-b-η₁                                    (2)ω_bi =ub-η₁ (2)

式中：ω_bi为理想状态下的载体轨道角速率，u为实际微陀螺输出，b为陀螺漂移，η₁为陀螺漂移的高斯白噪声误差。In the formula: ω_bi is the angular velocity of the carrier orbit in the ideal state, u is the actual micro-gyro output, b is the gyro drift, and η₁ is the Gaussian white noise error of the gyro drift.

E[η₁(t)]＝0E[η₁ (t)]=0

$\mathrm{<span><span>E</span>E.</span>}<span><span>[</span>[</span>{\mathrm{<span><span>\&eta;</span>\&eta;</span>}}_{\mathrm{<span><span>1</span>1</span>}}<span><span>(</span>(</span>\mathrm{<span><span>t</span>t</span>}<span><span>)</span>)</span>{\mathrm{<span><span>\&eta;</span>\&eta;</span>}}_{\mathrm{<span><span>1</span>1</span>}}^{\mathrm{<span><span>T</span>T</span>}}<span><span>(</span>(</span>{\mathrm{<span><span>t</span>t</span>}}^{<span><span>\&prime;</span>\&prime;</span>}<span><span>)</span>)</span><span><span>]</span>]</span><span><span>=</span>=</span>{\mathrm{<span><span>Q</span>Q</span>}}_{\mathrm{<span><span>1</span>1</span>}}<span><span>(</span>(</span>\mathrm{<span><span>t</span>t</span>}<span><span>)</span>)</span>\mathrm{<span><span>\&delta;</span>\&delta;</span>}<span><span>(</span>(</span>\mathrm{<span><span>t</span>t</span>}<span><span>-</span>-</span>{\mathrm{<span><span>t</span>t</span>}}^{<span><span>\&prime;</span>\&prime;</span>}<span><span>)</span>)</span>$

其中，t为时间。Among them, t is time.

又由于陀螺漂移b不为静态，η₂是陀螺漂移的随机游走噪声。And because the gyro drift b is not static, η₂ is the random walk noise of the gyro drift.

$\frac{\mathrm{<span><span>d</span>d</span>}}{\mathrm{<span><span>dt</span>dt</span>}}\mathrm{<span><span>b</span>b</span>}<span><span>=</span>=</span>{\mathrm{<span><span>\&eta;</span>\&eta;</span>}}_{\mathrm{<span><span>2</span>2</span>}}<span><span>-</span>-</span><span><span>-</span>-</span><span><span>-</span>-</span><span><span>(</span>(</span>\mathrm{<span><span>3</span>3</span>}<span><span>)</span>)</span>$

该随机过程的特征满足：The characteristics of this random process satisfy:

E[η₂(t)]＝0E[η₂ (t)]=0

$\mathrm{<span><span>E</span>E.</span>}<span><span>[</span>[</span>{\mathrm{<span><span>\&eta;</span>\&eta;</span>}}_{\mathrm{<span><span>2</span>2</span>}}<span><span>(</span>(</span>\mathrm{<span><span>t</span>t</span>}<span><span>)</span>)</span>{\mathrm{<span><span>\&eta;</span>\&eta;</span>}}_{\mathrm{<span><span>2</span>2</span>}}^{\mathrm{<span><span>T</span>T</span>}}<span><span>(</span>(</span>{\mathrm{<span><span>t</span>t</span>}}^{<span><span>\&prime;</span>\&prime;</span>}<span><span>)</span>)</span><span><span>]</span>]</span>{<span><span>=</span>=</span>\mathrm{<span><span>Q</span>Q</span>}}_{\mathrm{<span><span>2</span>2</span>}}<span><span>(</span>(</span>\mathrm{<span><span>t</span>t</span>}<span><span>)</span>)</span>\mathrm{<span><span>\&delta;</span>\&delta;</span>}<span><span>(</span>(</span>\mathrm{<span><span>t</span>t</span>}<span><span>-</span>-</span>{\mathrm{<span><span>t</span>t</span>}}^{<span><span>\&prime;</span>\&prime;</span>}<span><span>)</span>)</span>$

3)磁强计测量模型3) Magnetometer measurement model

${\mathrm{<span><span>B</span>B</span>}}_{\mathrm{<span><span>b</span>b</span>}}^{\mathrm{<span><span>b</span>b</span>}}<span><span>=</span>=</span>{\mathrm{<span><span>C</span>C</span>}}_{\mathrm{<span><span>i</span>i</span>}}^{\mathrm{<span><span>b</span>b</span>}}<span><span>\&CenterDot;</span>\&CenterDot;</span>{\mathrm{<span><span>B</span>B</span>}}_{\mathrm{<span><span>b</span>b</span>}}^{\mathrm{<span><span>i</span>i</span>}}<span><span>-</span>-</span><span><span>-</span>-</span><span><span>-</span>-</span><span><span>(</span>(</span>\mathrm{<span><span>4</span>4</span>}<span><span>)</span>)</span>$

式中：B_b^b为磁强计测量的载体坐标系下的地磁场矢量，B_bⁱ为由国际地磁模型(IGRF)计算出的惯性系下的地磁矢量，C_i^b惯性坐标系到载体坐标系的姿态矩阵。In the formula: B_b^b is the geomagnetic vector in the carrier coordinate system measured by the magnetometer, B_bi^is the geomagnetic vector in the inertial system calculated by the International Geomagnetic Model (IGRF), and C_i^{b is} the vector from the inertial coordinate system to the carrier The pose matrix of the coordinate system.

然后，通过组合定姿滤波器进行姿态解算，具体流程如图3所示。Then, the attitude calculation is performed by combining the attitude-fixing filters, the specific process is shown in Figure 3.

定义误差四元数为由姿态估计值向真实值转动所需的四元数：Define the error quaternion as the quaternion required to rotate from the pose estimate to the true value:

$\mathrm{<span><span>\&delta;</span>\&delta;</span>}\stackrel{<span><span>\&OverBar;</span>\&OverBar;</span>}{\mathrm{<span><span>q</span>q</span>}}<span><span>=</span>=</span>\stackrel{<span><span>\&OverBar;</span>\&OverBar;</span>}{\mathrm{<span><span>q</span>q</span>}}<span><span>\&CircleTimes;</span>\&CircleTimes;</span>{\stackrel{<span><span>^</span>^</span>}{\stackrel{<span><span>\&OverBar;</span>\&OverBar;</span>}{\mathrm{<span><span>q</span>q</span>}}}}^{<span><span>-</span>-</span>\mathrm{<span><span>1</span>1</span>}}<span><span>\&ap;</span>\&ap;</span>\left[\begin{array}{c}\mathrm{<span><span>\&delta;q</span>\&delta;q</span>}\\ \mathrm{<span><span>1</span>1</span>}\end{array}\right]<span><span>-</span>-</span><span><span>-</span>-</span><span><span>-</span>-</span><span><span>(</span>(</span>\mathrm{<span><span>5</span>5</span>}<span><span>)</span>)</span>$

q＝[q q₄]^T为真实姿态四元数，

为姿态估计四元数，δ q是误差四元数。q=[q q₄ ]^T is the real attitude quaternion,

is the pose estimation quaternion, and δ q is the error quaternion.

根据上述系统模型，设状态向量和估计误差为According to the above system model, let the state vector and estimation error be

状态向量：$x=\left[\begin{array}{c}\stackrel{\&OverBar;}{q}\\ b\end{array}\right]---\left(6\right)$State vector:$x=\left[\begin{array}{c}\stackrel{\&OverBar;}{q}\\ b\end{array}\right]---\left(6\right)$

误差向量：$\mathrm{\&Delta;x}=\left[\begin{array}{c}\mathrm{\&delta;q}\\ b-\hat{b}\end{array}\right]=\left[\begin{array}{c}\mathrm{\&delta;q}\\ \mathrm{\&Delta;b}\end{array}\right]---\left(7\right)$Error vector:$\mathrm{\&Delta;x}=\left[\begin{array}{c}\mathrm{\&delta;q}\\ b-\hat{b}\end{array}\right]=\left[\begin{array}{c}\mathrm{\&delta;q}\\ \mathrm{\&Delta;b}\end{array}\right]---\left(7\right)$

由卫星运动方程by satellite motion equation

$\frac{\mathrm{<span><span>d</span>d</span>}\stackrel{<span><span>\&OverBar;</span>\&OverBar;</span>}{\mathrm{<span><span>q</span>q</span>}}}{\mathrm{<span><span>dt</span>dt</span>}}<span><span>=</span>=</span>\frac{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>2</span>2</span>}}\stackrel{<span><span>\&OverBar;</span>\&OverBar;</span>}{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}<span><span>\&CircleTimes;</span>\&CircleTimes;</span>\stackrel{<span><span>\&OverBar;</span>\&OverBar;</span>}{\mathrm{<span><span>q</span>q</span>}}<span><span>-</span>-</span><span><span>-</span>-</span><span><span>-</span>-</span><span><span>(</span>(</span>\mathrm{<span><span>8</span>8</span>}<span><span>)</span>)</span>$

$\frac{\mathrm{<span><span>d</span>d</span>}}{\mathrm{<span><span>dt</span>dt</span>}}\stackrel{<span><span>^</span>^</span>}{\stackrel{<span><span>\&OverBar;</span>\&OverBar;</span>}{\mathrm{<span><span>q</span>q</span>}}}<span><span>=</span>=</span>\frac{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>2</span>2</span>}}\stackrel{<span><span>^</span>^</span>}{\stackrel{<span><span>\&OverBar;</span>\&OverBar;</span>}{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}}<span><span>\&CircleTimes;</span>\&CircleTimes;</span>\stackrel{<span><span>^</span>^</span>}{\stackrel{<span><span>\&OverBar;</span>\&OverBar;</span>}{\mathrm{<span><span>q</span>q</span>}}}<span><span>-</span>-</span><span><span>-</span>-</span><span><span>-</span>-</span><span><span>(</span>(</span>\mathrm{<span><span>9</span>9</span>}<span><span>)</span>)</span>$

得：$\frac{d}{\mathrm{dt}}\mathrm{\&delta;}\stackrel{\&OverBar;}{q}=\frac{1}{2}[\widehat{\stackrel{\&OverBar;}{\mathrm{\&omega;}}}\&CircleTimes;\mathrm{\&delta;}\stackrel{\&OverBar;}{q}-\mathrm{\&delta;}\stackrel{\&OverBar;}{q}\&CircleTimes;\widehat{\stackrel{\&OverBar;}{\mathrm{\&omega;}}}]+\frac{1}{2}\mathrm{\&delta;}\stackrel{\&OverBar;}{\mathrm{\&omega;}}\&CircleTimes;\mathrm{\&delta;}\stackrel{\&OverBar;}{q}---\left(10\right)$have to:$\frac{d}{\mathrm{dt}}\mathrm{\&delta;}\stackrel{\&OverBar;}{q}=\frac{1}{2}[\widehat{\stackrel{\&OverBar;}{\mathrm{\&omega;}}}\&CircleTimes;\mathrm{\&delta;}\stackrel{\&OverBar;}{q}-\mathrm{\&delta;}\stackrel{\&OverBar;}{q}\&CircleTimes;\widehat{\stackrel{\&OverBar;}{\mathrm{\&omega;}}}]+\frac{1}{2}\mathrm{\&delta;}\stackrel{\&OverBar;}{\mathrm{\&omega;}}\&CircleTimes;\mathrm{\&delta;}\stackrel{\&OverBar;}{q}---\left(10\right)$

其中：$\mathrm{\&delta;}\stackrel{\&OverBar;}{\mathrm{\&omega;}}=\left[\begin{array}{c}\mathrm{\&omega;}-\widehat{\mathrm{\&omega;}}\\ 0\end{array}\right]$in:$\mathrm{\&delta;}\stackrel{\&OverBar;}{\mathrm{\&omega;}}=\left[\begin{array}{c}\mathrm{\&omega;}-\widehat{\mathrm{\&omega;}}\\ 0\end{array}\right]$

忽略二阶项，从而得到系统状态方程：Neglecting the second-order terms, the state equation of the system is obtained:

$\frac{\mathrm{<span><span>d</span>d</span>}}{\mathrm{<span><span>dt</span>dt</span>}}\left[\begin{array}{c}\mathrm{<span><span>\&delta;q</span>\&delta;q</span>}\\ \mathrm{<span><span>\&Delta;b</span>\&Delta;b</span>}\end{array}\right]<span><span>=</span>=</span>\left[\begin{array}{cc}<span><span>[</span>[</span>\stackrel{<span><span>^</span>^</span>}{\mathrm{<span><span>\&omega;</span>\&omega;</span>}}<span><span>(</span>(</span>\mathrm{<span><span>t</span>t</span>}<span><span>)</span>)</span><span><span>\&times;</span>\&times;</span><span><span>]</span>]</span>& <span><span>-</span>-</span>\frac{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>2</span>2</span>}}{\mathrm{<span><span>I</span>I</span>}}_{\mathrm{<span><span>3</span>3</span>}<span><span>\&times;</span>\&times;</span>\mathrm{<span><span>3</span>3</span>}}\\ {\mathrm{<span><span>O</span><figure-callout\; label="o"\; filenames="A20051001122200082.png"\; state="\{\{state\}\}">o</figure-callout></span>}}_{\mathrm{<span><span>3</span>3</span>}<span><span>\&times;</span>\&times;</span>\mathrm{<span><span>3</span>3</span>}}& {\mathrm{<span><span>O</span><figure-callout\; label="o"\; filenames="A20051001122200082.png"\; state="\{\{state\}\}">o</figure-callout></span>}}_{\mathrm{<span><span>3</span>3</span>}<span><span>\&times;</span>\&times;</span>\mathrm{<span><span>3</span>3</span>}}\end{array}\right]<span><span>\&CenterDot;</span>\&Center\; Dot;</span>\left[\begin{array}{c}\mathrm{<span><span>\&delta;q</span>\&delta;q</span>}\\ \mathrm{<span><span>\&Delta;b</span>\&Delta;b</span>}\end{array}\right]<span><span>+</span>+</span>\left[\begin{array}{cc}<span><span>-</span>-</span>\frac{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>2</span>2</span>}}{\mathrm{<span><span>I</span>I</span>}}_{\mathrm{<span><span>3</span>3</span>}<span><span>\&times;</span>\&times;</span>\mathrm{<span><span>3</span>3</span>}}& {\mathrm{<span><span>O</span><figure-callout\; label="o"\; filenames="A20051001122200082.png"\; state="\{\{state\}\}">o</figure-callout></span>}}_{\mathrm{<span><span>3</span>3</span>}<span><span>\&times;</span>\&times;</span>\mathrm{<span><span>3</span>3</span>}}\\ {\mathrm{<span><span>O</span><figure-callout\; label="o"\; filenames="A20051001122200082.png"\; state="\{\{state\}\}">o</figure-callout></span>}}_{\mathrm{<span><span>3</span>3</span>}<span><span>\&times;</span>\&times;</span>\mathrm{<span><span>3</span>3</span>}}& {\mathrm{<span><span>I</span>I</span>}}_{\mathrm{<span><span>3</span>3</span>}<span><span>\&times;</span>\&times;</span>\mathrm{<span><span>3</span>3</span>}}\end{array}\right]<span><span>\&CenterDot;</span>\&Center\; Dot;</span>\left[\begin{array}{c}{\mathrm{<span><span>\&eta;</span>\&eta;</span>}}_{\mathrm{<span><span>1</span>1</span>}}\\ {\mathrm{<span><span>\&eta;</span>\&eta;</span>}}_{\mathrm{<span><span>2</span>2</span>}}\end{array}\right]<span><span>-</span>-</span><span><span>-</span>-</span><span><span>-</span>-</span><span><span>(</span>(</span>\mathrm{<span><span>11</span>11</span>}<span><span>)</span>)</span>$

其中，是

的斜对称阵。in, yes

The oblique symmetric matrix.

微磁强计敏感轴分别与星体坐标系的三轴平行，其测量量B_b为当地磁场强度在星体坐标系下的三轴分量，测量方程：The sensitive axes of the micro-magnetometer are parallel to the three axes of the astral coordinate system, and the measured quantity B_b is the three-axis component of the local magnetic field strength in the astral coordinate system. The measurement equation is:

${\stackrel{<span><span>^</span>^</span>}{\mathrm{<span><span>B</span>B</span>}}}_{\mathrm{<span><span>m</span>m</span>}}<span><span>=</span>=</span>\mathrm{<span><span>C</span>C</span>}<span><span>(</span>(</span>\stackrel{<span><span>^</span>^</span>}{\stackrel{<span><span>\&OverBar;</span>\&OverBar;</span>}{\mathrm{<span><span>q</span>q</span>}}}<span><span>)</span>)</span>{\mathrm{<span><span>B</span>B</span>}}_{\mathrm{<span><span>i</span>i</span>}}<span><span>-</span>-</span><span><span>-</span>-</span><span><span>-</span>-</span><span><span>(</span>(</span>\mathrm{<span><span>12</span>12</span>}<span><span>)</span>)</span>$

式中，为B_b估计值，

为由估计四元数得到的姿态矩阵，B_i为由IGRF计算得到的磁场强度。In the formula, is the estimated value of B_b ,

is the attitude matrix obtained by estimating the quaternion,_{and Bi} is the magnetic field strength calculated by IGRF.

定义测量向量为Define the measurement vector as

$\mathrm{<span><span>Z</span>Z</span>}<span><span>=</span>=</span>{\mathrm{<span><span>B</span>B</span>}}_{\mathrm{<span><span>b</span>b</span>}}<span><span>-</span>-</span>{\stackrel{<span><span>^</span>^</span>}{\mathrm{<span><span>B</span>B</span>}}}_{\mathrm{<span><span>b</span>b</span>}}<span><span>=</span>=</span><span><span>(</span>(</span>\mathrm{<span><span>C</span>C</span>}<span><span>(</span>(</span>\mathrm{<span><span>\&delta;</span>\&delta;</span>}\stackrel{<span><span>\&OverBar;</span>\&OverBar;</span>}{\mathrm{<span><span>q</span>q</span>}}<span><span>)</span>)</span><span><span>-</span>-</span>\mathrm{<span><span>I</span>I</span>}<span><span>)</span>)</span>{\stackrel{<span><span>^</span>^</span>}{\mathrm{<span><span>B</span>B</span>}}}_{\mathrm{<span><span>b</span>b</span>}}<span><span>\&ap;</span>\&ap;</span>\mathrm{<span><span>2</span>2</span>}<span><span>[</span>[</span>\mathrm{<span><span>\&delta;q</span>\&delta;q</span>}<span><span>\&times;</span>\&times;</span><span><span>]</span>]</span>{\stackrel{<span><span>^</span>^</span>}{\mathrm{<span><span>B</span>B</span>}}}_{\mathrm{<span><span>b</span>b</span>}}<span><span>+</span>+</span>\mathrm{<span><span>v</span>v</span>}<span><span>-</span>-</span><span><span>-</span>-</span><span><span>-</span>-</span><span><span>(</span>(</span>\mathrm{<span><span>13</span>13</span>}<span><span>)</span>)</span>$

[δq×]是δq的斜对称阵，ν为测量噪声。[δq×] is the skew symmetric matrix of δq, and ν is the measurement noise.

根据上述的系统状态方程和测量方程，在星上计算机系统内利用扩展卡尔曼滤波器对微陀螺、微加速度计与微磁强计测得的数据进行组合导航解算，从而获得微小卫星的实时姿态信息。以上数据经星上计算机的进一步坐标转换处理，可以得到最终的实时在轨姿态信息，为姿态控制提供依据。According to the above-mentioned system state equation and measurement equation, the extended Kalman filter is used in the on-board computer system to perform combined navigation calculation on the data measured by the micro-gyro, micro-accelerometer and micro-magnetometer, so as to obtain the real-time information of the micro-satellite. attitude information. The above data are further processed by the on-board computer for coordinate conversion, and the final real-time on-orbit attitude information can be obtained to provide a basis for attitude control.

本发明提出了基于MEMS的微陀螺、微加速度计和微磁强计的完整的组合姿态测量系统，可以有效提高微卫星姿态测量系统的可靠性及精度并减小其体积和重量。The invention proposes a complete combined attitude measurement system based on MEMS micro-gyro, micro-accelerometer and micro-magnetometer, which can effectively improve the reliability and precision of the micro-satellite attitude measurement system and reduce its volume and weight.

一方面，与传统单磁强计定姿系统相比，不需要递推动力学方程，滤波方程大大简化，计算量也显著下降；而且原有动力学递推精度由于受模型自身精度影响很大，无形当中影响了姿态测量精度，陀螺信息的引入提高了测量精度；另一方面，通过滤波算法估计陀螺漂移，将陀螺漂移估计反馈给微型惯性测量组合，便可得到更精确的角速度测量值，从而能够减小微型惯性测量组合误差随时间积累的不足，同时微型惯性测量组合作为完全自主式导航系统，也提高了抗干扰能力。另外，与目前地面上制导系统常用的惯性组合定姿系统相比，本发明所述系统有效克服了陀螺漂移等误差影响，解决了惯性定姿不能保证长期精度的问题。On the one hand, compared with the traditional single magnetometer attitude determination system, the recursive dynamic equation is not required, the filtering equation is greatly simplified, and the amount of calculation is also significantly reduced; and the original dynamic recursive accuracy is greatly affected by the accuracy of the model itself. Invisibly affecting the attitude measurement accuracy, the introduction of gyro information improves the measurement accuracy; on the other hand, the gyro drift is estimated through the filtering algorithm, and the gyro drift estimation is fed back to the micro-inertial measurement combination to obtain more accurate angular velocity measurements. It can reduce the accumulation of errors of the micro-inertial measurement combination over time, and at the same time, the micro-inertial measurement combination, as a completely autonomous navigation system, also improves the anti-jamming capability. In addition, compared with the inertial combination attitude determination system commonly used in the guidance system on the ground at present, the system of the present invention effectively overcomes the influence of errors such as gyro drift, and solves the problem that the inertial attitude determination cannot guarantee long-term accuracy.

本发明适合于空间飞行试验，特别是微小卫星的姿控系统等应用场合。与太阳敏感器、星敏感器等其它常用姿态敏感器件相比，其实时性强，不易受外界影响，具有良好的应用前景。The invention is suitable for space flight test, especially the attitude control system of tiny satellites and other application occasions. Compared with other commonly used attitude-sensitive devices such as sun sensors and star sensors, it has strong real-time performance and is not easily affected by the outside world, so it has a good application prospect.

Claims (2)

1. A miniature combination attitude measurement system for a microsatellite, characterized by: the miniature combined attitude measurement system comprises an inertia/magnetism combined measurement unit, a signal processing circuit and an on-board computer for storing a data processing program, wherein the inertia/magnetism combined measurement unit consists of three sets of sensor groups based on a micro electro mechanical system, which are respectively arranged on three orthogonal surfaces of a high-precision six-sided matrix, each sensor group comprises a micro gyroscope, a micro accelerometer and a micro magnetometer, the output end of each sensor group is connected with the signal processing circuit, output signals of each sensor group are transmitted to the on-board computer after being processed by the signal processing circuit, and the data processing program stored in the on-board computer executes the following steps:

defining an error quaternion as a quaternion required by the rotation from an attitude estimation value to a true value, firstly, constructing a state vector and an error vector by using the measured three-axis angular velocity and linear acceleration of the microsatellite and the error quaternion to further obtain a system state equation; meanwhile, a measurement equation is constructed through the triaxial component of the magnetic field intensity obtained in real time under the satellite coordinate system, then, data measured by the micro gyroscope, the micro accelerometer and the micro magnetometer are input into an extended Kalman filter by using the system state equation and the measurement equation, and the attitude estimation of the micro combined attitude measurement system is carried out to obtain the real-time attitude information of the microsatellite.

2. The miniature combined attitude measurement system for microsatellites according to claim 1, wherein: the signal processing circuit is integrated at the bottom of the high-precision six-sided base body and comprises a filter circuit, a signal amplification circuit, an A/D conversion circuit and a serial interface, wherein the filter circuit, the signal amplification circuit, the A/D conversion circuit and the serial interface are sequentially used for completing signal filtering, amplification and A/D conversion, processed output signals of the micro gyroscope, the micro accelerometer and the micro magnetometer are uniformly converted into a range of-5V to +5V, and the serial interface in the signal processing circuit is connected with the on-board computer through an aerospace connector fixed on the base body.

Images