阅读说明：本技术 一种激光捷联惯组的加速度测量通道温度补偿方法及系统 (Acceleration measurement channel temperature compensation method and system of laser strapdown inertial measurement unit ) 是由 范源 陈家骏 欧阳英图 于 2020-12-25 设计创作，主要内容包括：本发明公开了一种激光捷联惯组的加速度测量通道温度补偿方法及系统,其中温度补偿方法包括步骤：在I/F测量电路与加速度计相连形成加速度测量通道之前,获得I/F测量电路在无输入电流时的各通道输出值随温度变化的补偿函数K-0(t),其中t为I/F测量电路所在的环境温度值；在I/F测量电路与加速度计相连形成加速度测量通道之后,获取加速度测量通道的各通道的未经补偿的零次项输出值y-0以及实时环境温度值T；计算加速度测量通道的各通道的经温度补偿后的零次项输出值y-(0out),其中,y-(0out)＝y-0-K-0(T),K-0(T)为当自变量t取值为T时K-0(t)的值。本发明实现简单,对温度补偿时间几乎无要求,无额外功耗消耗,适用于启动快、功耗低的激光捷联惯组,能够显著提高激光捷联惯组的加速度测量通道的测量精度。(The invention discloses a temperature compensation method and a system for an acceleration measurement channel of a laser strapdown inertial measurement unit, wherein the temperature compensation method comprises the following steps: before the I/F measuring circuit is connected with the accelerometer to form an acceleration measuring channel, a compensation function K of the output value of each channel of the I/F measuring circuit changing with the temperature when no input current exists is obtained 0 (t), wherein t is an ambient temperature value at which the I/F measurement circuit is located; after the I/F measuring circuit is connected with the accelerometer to form an acceleration measuring channel, acquiring an uncompensated zero-order term output value y of each channel of the acceleration measuring channel 0 And a real-time ambient temperature value T; calculating the zero-order term output value y of each channel of the acceleration measurement channel after temperature compensation 0out Wherein, y 0out ＝y 0 ‑K 0 (T)，K 0 (T) is K when the independent variable T takes the value T 0 The value of (t). The invention has simple realization, almost no requirement on temperature compensation time, no extra power consumption, is suitable for the laser strapdown inertial unit with quick start and low power consumption,the measurement accuracy of the acceleration measurement channel of the laser strapdown inertial measurement unit can be remarkably improved.)

1. A temperature compensation method for an acceleration measurement channel of a laser strapdown inertial measurement unit is characterized by comprising the following steps:

step 1, before an I/F measuring circuit is connected with an accelerometer to form an acceleration measuring channel, a compensation function K of the output value of each channel of the I/F measuring circuit changing along with the temperature when no input current exists is obtained₀(t), wherein t is an ambient temperature value at which the I/F measurement circuit is located;

step 2, after the I/F measuring circuit is connected with the accelerometer to form an acceleration measuring channel, acquiring uncompensated zero-order output values y of all channels of the acceleration measuring channel₀And a real-time ambient temperature value T;

step 3, calculating the zero-order term output value y of each channel of the acceleration measurement channel after temperature compensation_0outWherein, y_0out＝y₀-K₀(T)，K₀(T) is when the independent variable T takes on the valueT time K₀The value of (t).

2. The method of claim 1, wherein the acceleration measurement channel temperature compensation method of the laser strapdown inertial measurement unit,

the step 1 also comprises the step of obtaining a compensation function K of the temperature change of the output value of each channel of the I/F measuring circuit when the exciting current is input before the I/F measuring circuit is connected with the accelerometer to form an acceleration measuring channel₁(t)；

The step 2 also comprises the step of obtaining the uncompensated primary term output value y of each channel of the acceleration measuring channel after the I/F measuring circuit is connected with the accelerometer to form the acceleration measuring channel₁And a real-time ambient temperature value T;

the step 3 also comprises the step of calculating the primary term output value y of each channel of the acceleration measurement channel after temperature compensation_1outWherein, y_1out＝(y₁-K₀(T))*K₁(T)，K₁(T) is K when the independent variable T takes the value T₁The value of (t).

3. The method of claim 1, wherein the compensation function K is a function of the acceleration measurement channel temperature₀(t) is obtained by a curve fitting method.

4. The method of claim 2, wherein the compensation function K is a function of the acceleration measurement channel temperature₁(t) is obtained by a curve fitting method.

5. The method for compensating for the temperature of the acceleration measurement channel of the laser strapdown inertial measurement unit of claim 2, wherein the excitation current value is 1 mA.

6. An acceleration measurement channel temperature compensation system of a laser strapdown inertial measurement unit is disclosed, wherein after an I/F measurement circuit is connected with an accelerometer to form an acceleration measurement channel, the acceleration measurement channel outputs each channelIs not compensated for the zero-order term output value y₀；

It is characterized by also comprising:

a compensation function obtaining unit: before the I/F measuring circuit is connected with the accelerometer to form an acceleration measuring channel, a compensation function K of the output value of each channel of the I/F measuring circuit changing along with the temperature when no input current exists is obtained₀(t), wherein t is an ambient temperature value at which the I/F measurement circuit is located;

a temperature value acquisition unit: the temperature acquisition module is used for acquiring an ambient temperature value of the I/F measuring circuit before the I/F measuring circuit is connected with the accelerometer to form an acceleration measuring channel and after the I/F measuring circuit is connected with the accelerometer to form the acceleration measuring channel;

a calculation unit: temperature compensated zero-order term output value y for each acceleration measurement channel_0outWherein, y_0out＝y₀-K₀(T)，K₀(T) is K when the independent variable T takes the value T₀And (T) is a real-time environment temperature value.

7. The system of claim 6, wherein the acceleration measurement channel outputs an uncompensated first order output y of each channel after the I/F measurement circuit is connected to the accelerometer to form the acceleration measurement channel₁；

A compensation function obtaining unit: and before the I/F measuring circuit is connected with the accelerometer to form an acceleration measuring channel, obtaining a compensation function K of the output value of each channel changing along with the temperature when the I/F measuring circuit has the input of the exciting current₁(t)；

A calculation unit: and is also used for calculating the temperature compensated first term output value y of each channel of the acceleration measurement channel_1outWherein, y_1out＝(y₁-K₀(T))*K₁(T)，K₁(T) is K when the independent variable T takes the value T₁The value of (t).

Technical Field

The invention belongs to the technical field of acceleration measurement channel temperature compensation, and particularly relates to a method and a system for compensating acceleration measurement channel temperature of a laser strapdown inertial measurement unit.

Background

The acceleration measuring channel is an important part in the laser strapdown inertial measurement unit and mainly comprises a quartz accelerometer and an I/F measuring circuit, the quartz accelerometer converts sensed acceleration into a current value to be output, and the I/F measuring circuit converts the current value output by the quartz accelerometer into a pulse change pulse value related to frequency to be used as a measured value of the acceleration measuring channel to be output. Whether the acceleration measurement channel can realize accurate measurement or not can directly influence the performance of the laser strapdown inertial measurement unit.

The factors influencing the measurement accuracy of the acceleration measurement channel comprise the structural principle of a quartz accelerometer, the performance factors of the manufacturing process and the like, and the factors also comprise an I/F measurement circuit in the acceleration measurement channel, wherein the error of the device caused by the working environment is influenced along with the temperature change, and the error of the I/F measurement circuit influenced by the temperature is coupled to the acceleration measurement channel, so that the measurement accuracy deviation of the acceleration measurement channel is increased.

According to the actually measured temperature of the acceleration measuring channel and the relation between the output pulse of the acceleration measuring channel and the temperature change, twelve-position calibration fitting is carried out on the rotary table, and real-time correction compensation is carried out on the output pulse of the acceleration measuring channel and the temperature, so that the influence of the environment temperature change on the measured value of the acceleration measuring channel is reduced, and the measuring precision is improved. However, in the whole temperature compensation process, drift errors caused by the ambient temperature to the I/F measuring circuit exist, so that the accuracy of an acceleration measuring channel is poor, and errors caused to a navigation system of the whole inertial measurement unit are large. In order to solve the problem that the measurement accuracy of an acceleration measurement channel is affected by temperature-affected errors of an I/F measurement circuit, the current method is to design a temperature compensation system for the I/F measurement circuit independently.

Disclosure of Invention

The invention aims to provide an improved acceleration measurement channel temperature compensation method and system of a laser strapdown inertial measurement unit, which are suitable for a high-precision laser strapdown inertial measurement unit and can obviously improve the measurement precision of the acceleration measurement channel of the laser strapdown inertial measurement unit, aiming at the problems that the error of the conventional I/F measurement circuit is influenced by the change of the device along with the temperature caused by the working environment, the error of the I/F measurement circuit influenced by the temperature is coupled to an acceleration measurement channel, and the error of the whole navigation system of the inertial measurement unit is larger.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a temperature compensation method for an acceleration measurement channel of a laser strapdown inertial measurement unit is characterized by comprising the following steps:

step 1, before an I/F measuring circuit is connected with an accelerometer to form an acceleration measuring channel, a compensation function K of the output value of each channel of the I/F measuring circuit changing along with the temperature when no input current exists is obtained₀(t), wherein t is an ambient temperature value at which the I/F measurement circuit is located;

step 2, after the I/F measuring circuit is connected with the accelerometer to form an acceleration measuring channel, acquiring uncompensated zero-order output values y of all channels of the acceleration measuring channel₀And a real-time ambient temperature value T;

step 3, calculating the zero-order term output value y of each channel of the acceleration measurement channel after temperature compensation_0outWherein, y_0out＝y₀-K₀(T)，K₀(T) is K when the independent variable T takes the value T₀The value of (t).

Further, the step 1 also includes, before the I/F measuring circuit is connected with the accelerometer to form the acceleration measuring channel, obtaining a compensation function K of the output value of each channel of the I/F measuring circuit changing with the temperature when the exciting current is input₁(t); the step 2 also comprises the step of obtaining the uncompensated primary term output value y of each channel of the acceleration measuring channel after the I/F measuring circuit is connected with the accelerometer to form the acceleration measuring channel₁And a real-time ambient temperature value T; the step 3 also comprises the step of calculating the primary term output value y of each channel of the acceleration measurement channel after temperature compensation_1outWherein, y_1out＝(y₁-K₀(T))*K₁(T)，K₁(T) is K when the independent variable T takes the value T₁The value of (t).

Preferably, the compensation function K₀(t) is prepared fromAnd (4) obtaining by a curve fitting method.

Preferably, the compensation function K₁(t) is obtained by a curve fitting method.

In a preferred embodiment, the excitation current value is 1 mA.

Based on the same invention concept, the invention also provides an acceleration measurement channel temperature compensation system of the laser strapdown inertial measurement unit, wherein after the I/F measurement circuit is connected with the accelerometer to form the acceleration measurement channel, the acceleration measurement channel outputs uncompensated zero-order output values y of all channels₀；

It is characterized by also comprising:

a compensation function obtaining unit: before the I/F measuring circuit is connected with the accelerometer to form an acceleration measuring channel, a compensation function K of the output value of each channel of the I/F measuring circuit changing along with the temperature when no input current exists is obtained₀(t), wherein t is an ambient temperature value at which the I/F measurement circuit is located;

a temperature value acquisition unit: the temperature acquisition module is used for acquiring an ambient temperature value of the I/F measuring circuit before the I/F measuring circuit is connected with the accelerometer to form an acceleration measuring channel and after the I/F measuring circuit is connected with the accelerometer to form the acceleration measuring channel;

a calculation unit: temperature compensated zero-order term output value y for each acceleration measurement channel_0outWherein, y_0out＝y₀-K₀(T)，K₀(T) is K when the independent variable T takes the value T₀And (T) is a real-time environment temperature value.

Furthermore, after the I/F measuring circuit is connected with the accelerometer to form an acceleration measuring channel, the acceleration measuring channel outputs uncompensated primary term output values y of all channels₁；

A compensation function obtaining unit: and before the I/F measuring circuit is connected with the accelerometer to form an acceleration measuring channel, obtaining a compensation function K of the output value of each channel changing along with the temperature when the I/F measuring circuit has the input of the exciting current₁(t)；

A calculation unit:and is also used for calculating the temperature compensated first term output value y of each channel of the acceleration measurement channel_1outWherein, y_1out＝(y₁-K₀(T))*K₁(T)，K₁(T) is K when the independent variable T takes the value T₁The value of (t).

The working principle of the invention is as follows: the method comprises the steps of firstly obtaining a compensation function of temperature change of output values of all channels of an I/F measuring circuit before installation, then obtaining uncompensated zero-order terms and/or one-time output values of all channels of an acceleration measuring channel after installation, and finally carrying out temperature compensation on the uncompensated output values by using the compensation function to obtain the compensated zero-order terms and/or one-time output values of the acceleration measuring channel.

Compared with the prior art, the method is simple to implement, almost has no requirement on temperature compensation time, has no extra power consumption, is suitable for the laser strapdown inertial measurement unit with quick start and low power consumption, and can remarkably improve the measurement precision of the acceleration measurement channel of the laser strapdown inertial measurement unit.

Drawings

FIG. 1 shows the zero-order pulse output value of a certain channel of an acceleration measurement channel without compensation of the present invention in a full temperature range.

FIG. 2 is a graph of the positive primary term pulse output over the full temperature range for a particular acceleration measurement channel without compensation by the present invention.

FIG. 3 is a negative primary term pulse output value over the full temperature range for a particular acceleration measurement channel without compensation by the present invention.

FIG. 4 shows the zero-order pulse output value of a certain channel of the acceleration measuring channel compensated by the present invention in the full temperature range.

FIG. 5 shows the output value of the positive primary term pulse of a certain channel of the acceleration measuring channel compensated by the present invention in the full temperature range.

FIG. 6 shows the negative primary term pulse output value of a certain channel of the acceleration measuring channel compensated by the present invention in the full temperature range.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to the following embodiments and accompanying drawings.

A temperature compensation method for an acceleration measurement channel of a laser strapdown inertial measurement unit comprises the following steps:

step 1, before an I/F measuring circuit is connected with an accelerometer to form an acceleration measuring channel, a compensation function K of the output value of each channel of the I/F measuring circuit changing along with the temperature when no input current exists is obtained₀(t), wherein t is an ambient temperature value at which the I/F measurement circuit is located;

step 2, after the I/F measuring circuit is connected with the accelerometer to form an acceleration measuring channel, acquiring uncompensated zero-order output values y of all channels of the acceleration measuring channel₀And a real-time ambient temperature value T;

step 3, calculating the zero-order term output value y of each channel of the acceleration measurement channel after temperature compensation_0outWherein, y_0out＝y₀-K₀(T)，K₀(T) is K when the independent variable T takes the value T₀The value of (t).

The step 1 also comprises the step of obtaining a compensation function K of the temperature-dependent change of the output value of each channel when the I/F measuring circuit inputs an excitation current (the excitation current value is preferably 1mA) before the I/F measuring circuit is connected with the accelerometer to form an acceleration measuring channel₁(t); the step 2 also comprises the step of obtaining the uncompensated primary term output value y of each channel of the acceleration measuring channel after the I/F measuring circuit is connected with the accelerometer to form the acceleration measuring channel₁And a real-time ambient temperature value T; the step 3 also comprises the step of calculating the primary term output value y of each channel of the acceleration measurement channel after temperature compensation_1outWherein, y_1out＝(y₁-K₀(T))*K₁(T)，K₁(T) is K when the independent variable T takes the value T₁The value of (t).

Preferably, the compensation function K₀(t) and a compensation function K₁(t) are obtained by a curve fitting method.

In this embodiment, the compensation function K₀(t) and a compensation function K₁(t) the curve fitting method is as follows:

firstly, an I/F measuring circuit is arranged in a temperature control box, the temperature control box controls the environment temperature of the I/F measuring circuit to change within the range of minus 20 ℃ to 70 ℃, a plurality of groups of one-to-one corresponding environment temperature values are obtained through the detection of an upper computer, and pulse value data are output by the I/F measuring circuit.

Then, in MATLAB, off-line curve fitting is carried out on the obtained environment temperature values and I/F measuring circuit output pulse value data which are in one-to-one correspondence to a plurality of groups to obtain an optimal fitting function K₀(t)。

Obtaining a compensation function K corresponding to a zero-order term₀(t) is:

K₀(t)＝K_0ntⁿ+...+K₀₅t⁵+K₀₄t⁴+K₀₃t³+K₀₂t²+K₀₁t¹+K₀₀t⁰

wherein n is the maximum number of curve fitting and the coefficient K_0n、...K₀₅、K₀₄、K₀₃、K₀₂、K₀₁、K₀₀The significance number of n-degree term coefficients obtained in MATLAB curve fitting is not less than 8 bits. After temperature compensation is ensured, the zero stability is less than 2ppm at most at the full temperature.

In this embodiment, the compensation function K₁(t) the curve fitting method is as follows:

firstly, an I/F measuring circuit is arranged in a temperature control box, 1mA excitation current (used for simulating a quartz accelerometer) is input into the I/F measuring circuit, the temperature control box is used for controlling the change of the environment temperature of the I/F measuring circuit within the range of minus 20-70 ℃, and a plurality of groups of environment temperature values which correspond one to one and output pulse value data of the I/F measuring circuit are obtained through the detection of an upper computer.

Then, in MATLAB, off-line curve fitting is carried out on the obtained environment temperature values and I/F measuring circuit output pulse value data which are in one-to-one correspondence to a plurality of groups to obtain an optimal fitting function K₁(t)。

Obtaining a compensation function K corresponding to the first order term₁(t) is:

K₁(t)＝20000/(y₁-K₀(t))＝K_1ntⁿ+...+K₁₅t⁵+K₁₄t⁴+K₁₃t³+K₁₂t²+K₁₁t¹+K₁₀t⁰

wherein n is the maximum number of curve fitting and the coefficient K_1n、...K₁₅、K₁₄、K₁₃、K₁₂、K₁₁、K₁₀The significance number of n-degree term coefficients obtained in MATLAB curve fitting is not less than 8 bits. After temperature compensation is ensured, the stability of the scale factor is maximally less than 12ppm at the full temperature.

When curve fitting is performed on the compensation function of the first-order term, positive excitation current and negative excitation current are respectively input, and curve fitting is respectively performed. Correspondingly, when temperature compensation is carried out, the output of the acceleration measuring channel is compensated by using the compensation function corresponding to the corresponding positive/negative excitation current.

In this embodiment, a dedicated high-precision multifunctional calibrator 5500A is used to output a 1mA excitation current.

Correspondingly, the invention also provides an acceleration measurement channel temperature compensation system of the laser strapdown inertial measurement unit, wherein after the I/F measurement circuit is connected with an accelerometer (such as a quartz accelerometer) to form an acceleration measurement channel, the acceleration measurement channel outputs uncompensated zero-order term output values y of all channels₀(ii) a Further comprising:

a compensation function obtaining unit: before the I/F measuring circuit is connected with the accelerometer to form an acceleration measuring channel, a compensation function K of the output value of each channel of the I/F measuring circuit changing along with the temperature when no input current exists is obtained₀(t), wherein t is an ambient temperature value at which the I/F measurement circuit is located;

a temperature value acquisition unit: the temperature acquisition module is used for acquiring an ambient temperature value of the I/F measuring circuit before the I/F measuring circuit is connected with the accelerometer to form an acceleration measuring channel and after the I/F measuring circuit is connected with the accelerometer to form the acceleration measuring channel;

a calculation unit: temperature compensated zero-order term output value y for each acceleration measurement channel_0outWherein, y_0out＝y₀-K₀(T)，K₀(T) is K when the independent variable T takes the value T₀And (T) is a real-time environment temperature value.

Furthermore, after the I/F measuring circuit is connected with the accelerometer to form an acceleration measuring channel, the acceleration measuring channel outputs uncompensated primary term output values y of all channels₁；

A compensation function obtaining unit: and before the I/F measuring circuit is connected with the accelerometer to form an acceleration measuring channel, obtaining a compensation function K of the output value of each channel changing along with the temperature when the I/F measuring circuit has the input of the exciting current₁(t)；

A calculation unit: and is also used for calculating the temperature compensated first term output value y of each channel of the acceleration measurement channel_1outWherein, y_1out＝(y₁-K₀(T))*K₁(T)，K₁(T) is K when the independent variable T takes the value T₁The value of (t).

The working principle of the invention is as follows: the method comprises the steps of firstly obtaining a compensation function of temperature change of output values of all channels of an I/F measuring circuit before installation, then obtaining uncompensated zero-order terms and/or one-time output values of all channels of an acceleration measuring channel after installation, and finally carrying out temperature compensation on the uncompensated output values by using the compensation function to obtain the compensated zero-order terms and/or one-time output values of the acceleration measuring channel.

Referring to fig. 1 to 3, the pulse output value of a certain channel of the acceleration measurement channel without compensation of the present invention in the full temperature range is shown. It can be seen that the pulse output of the acceleration measuring channel is monotonous and smooth in change trend under the influence of temperature without the compensation of the invention.

Referring to fig. 4 to 6, the pulse output values of a certain channel of the acceleration measurement channel compensated by the present invention in the full temperature range are shown. The comparison shows that the measurement precision and the measurement stability of the acceleration measurement channel are obviously improved after the compensation of the method disclosed by the invention. See in particular table 1 below. In Table 1, K0x represents the zero-order term pulse output value of the x channel, K1x + represents the positive-going primary term pulse output value of the x channel, and K1 x-represents the positive-going negative-going primary term pulse output value of the x channel.

TABLE 1 temperature compensation verification accuracy of the method of the invention

As can be seen from Table 1, the zero-order hundred-second mean range is about 2.6ppm and the one-order hundred-second mean range is about 12ppm after compensation by the method of the present invention.

While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.