MEMS Inertial Navigation System

Abstract

This application relates to a MEMS inertial navigation system, comprising: a MEMS sensor array and a controller; wherein, the MEMS sensor array includes multiple MEMS sensors installed in a predetermined layout, and the output terminal of each MEMS sensor is connected to the controller via a control switch; the control terminal of the control switch is connected to the controller and is turned on or off under the control of the controller; each MEMS sensor in the sensor array outputs first inertial measurement data through its output terminal; the controller outputs a switch control signal to the control switch to control at least one MEMS sensor to turn on or off the output of the first inertial measurement data; the controller receives the first inertial measurement data output by each of the activated MEMS sensors at the acquisition time, and outputs second inertial measurement data after calibration processing; this technical solution can control the use of the first inertial measurement data of some superior MEMS sensors to calibrate and acquire the second inertial measurement data, thereby improving measurement accuracy and enhancing the performance of inertial navigation.

Description

Technical Field

[0001] This application relates to the field of inertial navigation technology, and in particular to a MEMS inertial navigation system. Background Technology

[0002] An inertial navigation system (INS) is an important navigation device. MEMS inertial navigation systems typically have multiple built-in MEMS (Micro Electromechanical System) sensors. These MEMS sensors can measure parameters such as acceleration and angular acceleration, and then integrate them to obtain displacement information and real-time attitude information, injecting strong momentum into the leapfrog development of navigation, positioning, attitude perception and other technologies.

[0003] Typically, to reduce equipment costs, MEMS inertial navigation systems use consumer-grade MEMS sensors. However, due to the limitations of the manufacturing process of MEMS devices, consumer-grade MEMS devices are prone to large measurement errors due to quantization errors, random walks, zero-bias instability noise, nonlinearity, and thermal instability.

[0004] In known technologies, inertial measurement data is obtained by weighted averaging the measurement data from various MEMS sensors. However, the correction results in this scheme are easily affected by MEMS sensors in poor condition, thereby reducing the detection accuracy. Summary of the Invention

[0005] To address one of the aforementioned technical shortcomings, this application provides a MEMS inertial navigation system with higher measurement accuracy.

[0006] A MEMS inertial navigation system includes: a MEMS sensor array and a controller; wherein, the MEMS sensor array includes a plurality of MEMS sensors mounted in a predetermined layout, and the output terminal of each MEMS sensor is connected to the controller via a control switch;

[0007] The control terminal of the control switch is connected to the controller, and is turned on or off under the control of the controller;

[0008] Each MEMS sensor in the sensor array outputs first inertial measurement data through its output terminal;

[0009] The controller outputs a switch control signal to the control switch to control at least one MEMS sensor to turn on or off and output first inertial measurement data.

[0010] The controller receives the first inertial measurement data output by each activated MEMS sensor at the acquisition time, and outputs the second inertial measurement data after calibration processing.

[0011] In one embodiment, the MEMS sensors of the MEMS sensor array are arranged at mutually perpendicular angles.

[0012] In one embodiment, each MEMS sensor is further provided with a temperature sensor connected to the controller, which is used to detect the temperature data of the MEMS sensor and send it to the controller.

[0013] In one embodiment, the controller is connected to each MEMS sensor and each control switch via an I2C bus; wherein, the output terminal of the MEMS sensor communicates with the controller via an I2C communication interface, and the control terminal of the control switch is connected to the I2C bus via an I2C switch interface.

[0014] In one embodiment, the I2C communication interface and the I2C switch interface are arranged at intervals, with the I2C switch interface preceding the I2C communication interface; wherein the I2C communication interface and the I2C switch interface operate under the control of a clock pulse signal.

[0015] In one embodiment, the I2C bus includes a serial data line and a serial clock line, wherein each of the MEMS sensors and control switches is connected to the serial data line and the serial clock line, respectively.

[0016] The MEMS inertial navigation system described in one embodiment further includes: a clock generator for outputting clock pulse signals to a serial clock line.

[0017] In one embodiment, the controller is connected to the I2C bus via an encoder, and the control switch is connected to the I2C bus via a decoder;

[0018] The controller sends a switch control signal to the encoder, and the encoder encodes the switch control signal into a serial switch control code and sends it to each decoder via the I2C bus.

[0019] The decoder obtains its corresponding code value from the serial switch control code and sends it to the control switch.

[0020] The MEMS inertial navigation system described in one embodiment further includes:

[0021] Connect the power switches of each MEMS sensor to the controller, which is used to turn the power supply of the MEMS sensors on or off.

[0022] In one embodiment, the controller controls the disconnection of at least one MEMS sensor.

[0023] In the above technical solution, the control switch is turned on or off under the control of the controller, controlling at least one MEMS sensor to turn on or off and output first inertial measurement data; the controller receives the first inertial measurement data output by each of the turned-on MEMS sensors at the acquisition time, and outputs second inertial measurement data after calibration processing; this technical solution can control the use of first inertial measurement data from some of the better MEMS sensors to calibrate and acquire second inertial measurement data, thereby improving measurement accuracy and enhancing the effectiveness of inertial navigation.

[0024] Additional aspects and advantages of this application will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of this application. Attached Figure Description

[0025] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0026] Figure 1 This is a schematic diagram of the structure of a MEMS inertial navigation system according to one embodiment;

[0027] Figure 2 This is a schematic diagram of an example MEMS sensor layout;

[0028] Figure 3 This is a schematic diagram of the structure of another embodiment of a MEMS inertial navigation system;

[0029] Figure 4 This is a timing diagram of an example I2C interface. Detailed Implementation

[0030] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0031] Those skilled in the art will understand that, unless otherwise stated, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the word “comprising” as used in this application’s specification means the presence of the stated feature, integer, step, or operation, but does not preclude the presence or addition of one or more other features, integers, steps, or operations.

[0032] refer to Figure 1 As shown, Figure 1 This is a schematic diagram of a MEMS inertial navigation system according to one embodiment, including: a MEMS sensor array and a controller; wherein the MEMS sensor array includes multiple MEMS sensors installed in a predetermined layout, and the output terminal of each MEMS sensor is connected to the controller through a control switch.

[0033] The control terminal of the control switch is connected to the controller, and is turned on or off under the control of the controller; each MEMS sensor in the sensor array outputs first inertial measurement data through its output terminal; the controller outputs a switch control signal to the control switch to control at least one MEMS sensor to turn on or off and output the first inertial measurement data; the controller receives the first inertial measurement data output by each of the turned-on MEMS sensors at the acquisition time, and outputs second inertial measurement data after calibration processing; wherein, the turned-on sensors are several MEMS sensors with better performance, or the turned-off sensors are several MEMS sensors with poorer performance.

[0034] For example, as shown in the figure, the MEMS sensor array includes n MEMS sensors arranged in a predetermined layout. The MEMS sensor array consists of n MEMS sensors, each of which can be numbered 1, 2, ..., n. The n MEMS sensor array is named MEMS1, MEMS2, ..., MEMSn, where n ≥ 2. Each MEMS sensor is connected to the controller via a control switch, i.e., each MEMS sensor is connected to a control switch, as shown in the figure, where the control switches are represented as S1, S2, ..., Sn. The output terminals of each MEMS sensor are connected to the controller.

[0035] For example, the first inertial measurement data detected by each MEMS sensor is output to the controller for processing, such as... Figure 1 In this process, the controller can output the first inertial measurement data collected from MEMS1, MEMS2, ..., MEMSn. The controller outputs switch control signals as needed to enable the first inertial measurement data output from some MEMS sensors and disable the first inertial measurement data output from some MEMS sensors. Preferably, m high-performance MEMS sensors can be selected, i.e., m MEMS sensors are chosen from MEMS1, MEMS2, ..., MEMSn, and the second inertial measurement data Q is obtained by correcting the first inertial measurement data from these m target MEMS sensors.

[0036] For example, for the m MEMS sensors with better performance, they can be the first m MEMS sensors whose first inertial measurement data deviates less from the second inertial measurement data.

[0037] As in the above embodiment, the controller can turn off the output of first inertial measurement data from some MEMS sensors with poor performance and turn on the output of first inertial measurement data from some MEMS sensors with poor performance. Then, the first inertial measurement data output by these MEMS sensors with better performance is used to correct and obtain second inertial measurement data, thereby improving the measurement accuracy of the corrected output second inertial measurement data and enhancing the effectiveness of inertial navigation.

[0038] In one embodiment, the MEMS inertial navigation system of this application has MEMS sensors of a MEMS sensor array arranged at mutually perpendicular angles.

[0039] like Figure 2 As shown, Figure 2 This is a schematic diagram of an example MEMS sensor layout. Taking MEMS1, MEMS2, and MEMS3 as examples, according to the marked x, y, and z axes of the MEMS sensors, the x-axis of MEMS1, the x-axis of MEMS2, and the x-axis of MEMS3 are mutually perpendicular. Similarly, the y-axis of MEMS1, the y-axis of MEMS2, and the y-axis of MEMS3 are mutually perpendicular. The z-axis of MEMS1, the z-axis of MEMS2, and the z-axis of MEMS3 are also mutually perpendicular.

[0040] As in the above embodiment, arranging the MEMS sensors of each MEMS sensor array at mutually perpendicular angles can cancel out directional errors between different devices and improve the measurement accuracy of the MEMS inertial navigation system.

[0041] In one embodiment, the MEMS inertial navigation system of this application, such as Figure 3 As shown, Figure 3 This is a schematic diagram of another embodiment of a MEMS inertial navigation system. The controller is connected to each MEMS sensor and each control switch via an I2C bus. The output terminals of the MEMS sensors communicate with the controller via an I2C communication interface, and the control terminals of the control switches are connected to the I2C bus via an I2C switch interface.

[0042] Furthermore, the I2C communication interface and the I2C switch interface are arranged at intervals, with the I2C switch interface preceding the I2C communication interface; wherein, the I2C communication interface and the I2C switch interface operate under the control of a clock pulse signal.

[0043] Furthermore, the I2C bus may include a serial data line SDA and a serial clock line SCL, wherein each of the MEMS sensors and control switches is connected to the serial data line SDA and the serial clock line SCL, respectively.

[0044] Furthermore, the MEMS inertial navigation system may also include a clock generator CG for outputting a clock pulse signal CLK to the serial clock line SCL.

[0045] Specifically, the controller connects to each MEMS sensor and each control switch via an I2C bus; the MEMS sensors communicate with the controller via an I2C communication interface, and the control switches communicate with the controller via an I2C switch interface; the I2C communication interface and the I2C switch interface are set at intervals, with the I2C switch interface preceding the I2C communication interface; the I2C communication interface and the I2C switch interface operate under the control of the clock pulse signal CLK.

[0046] refer to Figure 4 As shown, Figure 4 This is a timing diagram of an example I2C interface. As shown in the figure, the I2C switch interfaces corresponding to MEMS1, MEMS2, ..., MEMSn are I2C11, I2C12, ..., I2C1n, and the corresponding I2C communication interfaces are I2C21, I2C22, ..., I2C2n. Under the control of the clock pulse signal CLK, a communication interaction between the I2C switch interface and the I2C communication interface is executed on the rising edge of the clock pulse signal CLK. For example, firstly, the I2C21 switch interface receives the switch control signal to turn the output of MEMS1 on or off, and then the I2C21 communication interface transmits the first inertial measurement data. And so on. All the interaction communication between the I2C communication interface and the I2C switch interface is completed within a certain number of clock pulses, which can achieve the effect of parallel I2C bus.

[0047] The technical solution in the above embodiment adopts a simulated parallel I2C bus scheme, which can accurately acquire MEMS measurement values ​​at the same time. Each MEMS sensor reads the measurement data simultaneously, further improving the measurement accuracy of the MEMS inertial navigation system.

[0048] In one embodiment, the MEMS inertial navigation system of this application further includes a temperature sensor connected to the controller on each MEMS sensor, used to detect the temperature data of the MEMS sensor and send it to the controller.

[0049] like Figure 3 As shown, temperature sensors T1, T2, ..., Tn correspond to MEMS1, MEMS2, ..., MEMSn, respectively. The controller can detect the temperature data of MEMS1, MEMS2, ..., MEMSn through T1, T2, ..., Tn. The controller can then use this temperature data to adjust the calibration parameters, thereby improving the measurement accuracy of the MEMS inertial navigation system.

[0050] In one embodiment, in the MEMS inertial navigation system of this application, the controller is connected to the I2C bus via an encoder, and the control switch is connected to the I2C bus via a decoder; the controller sends a switch control signal to the encoder, the encoder encodes the switch control signal into a serial switch control code and sends it to each decoder via the I2C bus; the decoder obtains its corresponding code value from the serial switch control code and sends it to the control switch.

[0051] like Figure 3 As shown, the controller is connected to the I2C bus via encoder M, and the control switch is connected to the I2C bus via decoder. The controller sends a switch control signal to encoder M. The encoder encodes the switch control signal into a serial switch control code and sends it to each decoder via the I2C bus. The n decoders in the figure are represented as D1, D2, ..., Dn. The decoder can obtain its corresponding code value from the serial switch control code and send it to the control switch.

[0052] For example, the controller sends the switch control signal to the encoder for encoding, which can be encoded into level signals such as "0" and "1". Then, according to the frequency of the clock pulse signal CLK, the switch control signal can be encoded into serial switch control codes corresponding to the I2C switch interfaces I2C11, I2C12, ..., I2C1n. On the rising edge of the clock pulse signal CLK, an I2C switch interface communication interaction is performed. The decoders are represented as D1, D2, ..., Dn, which can decode their own code values ​​to complete the switch control of the corresponding MEMS sensor.

[0053] As in the above embodiments, the controller can implement relevant logic control through encoders and decoders, thereby enabling fast and accurate control of MEMS sensors and ensuring data processing stability.

[0054] In one embodiment, the MEMS inertial navigation system of this application may further include: power switches connected to each MEMS sensor respectively, and each power switch connected to a controller for turning the power supply of the MEMS sensor on or off.

[0055] Specifically, such as Figure 3 In the process, each MEMS sensor MEMS1, MEMS2, ..., MEMSn is equipped with power switches R1, R2, ..., Rn, etc.; these power switches are connected to the power supply Vcc and are controlled by a controller.

[0056] For example, the controller can choose to disconnect or connect the MEMS sensor based on the current operating mode; for instance, in high-precision mode, it can disconnect (i.e. disable) the MEMS sensor with poor performance, while in low-precision mode, it can connect and use the MEMS sensor with poor performance.

[0057] As described in the above embodiments, the power switch of the MEMS sensor can optimize the usage time of the MEMS sensor, fully utilize each MEMS sensor while ensuring the accuracy of the output second inertial measurement data, protect the core MEMS sensor, and extend its working life.

[0058] Based on the technical solutions of the various embodiments of the MEMS inertial navigation system in this application, a variety of correction schemes can be applied.

[0059] For example, the controller can calculate the performance status of each MEMS sensor, periodically activate the acquisition of m MEMS sensors for calibration calculation to obtain the second inertial measurement data Q; where m≥2, nm≥1, and n represents the number of MEMS sensor arrays.

[0060] For example, the controller can dynamically select MEMS sensors. At each sampling time, it starts collecting the first inertial measurement data of m MEMS sensors, performs correction calculations to obtain the second inertial measurement data Q, and simultaneously calculates the m MEMS sensors with the smallest deviation from the second inertial measurement data for use in the next acquisition calculation; where m≥2, nm≥1, and n represents the number of MEMS sensor arrays.

[0061] For example, the controller calibration method can be as follows: First inertial measurement data q1, q2, ..., qm output from m MEMS sensors are read respectively; the first inertial measurement data are calibrated using independent pre-stage calibration coefficients corresponding to the m target MEMS sensors. Assuming the pre-stage calibration coefficients corresponding to each MEMS sensor are k1, k2, ..., km, then the first inertial measurement data q1, q2, ..., qm output from sensors MEMS1, MEMS2, ..., MEMSm are calibrated using k1, k2, ..., km respectively. The formula for calculating the second inertial measurement data can be expressed as follows:

[0062] Q=K×∑(k1q1+k2q2+…kmqm)k1+k2+…km=1

[0063] Where Q is the second inertial measurement data and K is the set correction coefficient.

[0064] The above description is only a partial embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A MEMS inertial navigation system, characterized in that, include: MEMS sensor array and controller; wherein, the MEMS sensor array includes multiple MEMS sensors installed in a predetermined layout, and the output terminal of each MEMS sensor is connected to the controller through a control switch; The control terminal of the control switch is connected to the controller, and is turned on or off under the control of the controller; Each MEMS sensor in the sensor array outputs first inertial measurement data through its output terminal; The controller outputs a switch control signal to the control switch to control at least one MEMS sensor to turn on or off and output first inertial measurement data. The controller receives the first inertial measurement data output by each activated MEMS sensor at the acquisition time, and outputs the second inertial measurement data after calibration processing.

2. The MEMS inertial navigation system according to claim 1, characterized in that, The MEMS sensors in the MEMS sensor array are arranged at mutually perpendicular angles.

3. The MEMS inertial navigation system according to claim 1, characterized in that, Each MEMS sensor is also equipped with a temperature sensor connected to the controller, which is used to detect the temperature data of the MEMS sensor and send it to the controller.

4. The MEMS inertial navigation system according to claim 1, characterized in that, The controller is connected to each MEMS sensor and each control switch via an I2C bus; the output of each MEMS sensor communicates with the controller via an I2C communication interface, and the control terminal of each control switch is connected to the I2C bus via an I2C switch interface.

5. The MEMS inertial navigation system according to claim 4, characterized in that, The I2C communication interface and the I2C switch interface are arranged at intervals, with the I2C switch interface preceding the I2C communication interface; wherein, the I2C communication interface and the I2C switch interface operate under the control of a clock pulse signal.

6. The MEMS inertial navigation system according to claim 5, characterized in that, The I2C bus includes a serial data line and a serial clock line, wherein each of the MEMS sensors and control switches is connected to the serial data line and the serial clock line respectively.

7. The MEMS inertial navigation system according to claim 5, characterized in that, Also includes: A clock generator is used to output clock pulse signals to a serial clock line.

8. The MEMS inertial navigation system according to claim 1, characterized in that, The controller is connected to the I2C bus via an encoder, and the control switch is connected to the I2C bus via a decoder. The controller sends a switch control signal to the encoder, and the encoder encodes the switch control signal into a serial switch control code and sends it to each decoder via the I2C bus. The decoder obtains its corresponding code value from the serial switch control code and sends it to the control switch.

9. The MEMS inertial navigation system according to claim 1, characterized in that, Also includes: Connect the power switches of each MEMS sensor to the controller, which is used to turn the power supply of the MEMS sensors on or off.

10. The MEMS inertial navigation system according to claim 9, characterized in that, The controller controls the disconnection of at least one MEMS sensor.

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