Compared to other gyro the dynamic performance of optical-fiber gyro was better and the price was cheap. Optical-fiber gyro was suit to build SINS. By the way, zero bias of optical-fiber gyro was sensitive to temperature, and the compensation technique was a hot point in INS research. According to the above situation, based on one type optical-fiber gyro, the influence mechanism about temperature to optical-fiber gyro zero bias was studied, and a test method was designed, the experiment results was analyzed, finally based on multinomial simulation a compensation math model was established, and the research result discovered that temperature was a big influence to optical-fiber gyro zero bias, and it can be fixed by a compensation math model based on multinomial simulation.

Gyro was the core component of inertial navigation equipment, and it was the key factor to determine the position and attitude accuracy of inertial navigation equipment. At present, the traditional liquid lifting gyro has entered the technical stability period, the accuracy has been difficult to break through; laser gyro technology has also been basically mature, and entered the stage of engineering application. Compared with the liquid lifting gyro, optical fiber gyro has the advantages of simple structure, fast starting, long service life, small volume and so on; Compared with the laser gyro, with lower price and higher dynamic performance, optical-fiber gyro was more suitable for construction of strap down inertial system.

The temperature was main factors affecting the performance of optical-fiber gyro[

The optical-fiber gyro used in this experiment was a kind of advanced high precision, which requires the gyro performance index: zero bias stability was better than 0.02º/h, and the scale factor stability was better than 10ppm.

Test hardware conditions include temperature control turntable and supporting facilities, the specific configuration was as follows:

The temperature range was between -20°C and +60°C; the output range was 0.01º/s to 1000º/s; the rate stability was 1×10-4; the temperature stability was ±0.5°C.

The vibration isolation foundation avoids the interference of external vibration to the test. The data acquisition device was used for the acquisition of gyro data, and the turntable control computer was used for the control of turntable and the collection of gyro data.

Fig.

Equipment connection about temperature test

In order to test the temperature characteristics of the optical-fiber gyro, a total of 8 fixed temperature gyro zero bias tests were arranged according to the experimental scheme. 4 experiments were conducted at each fixed temperature, and the results of an experiment were shown in table

RESULTS ABOUT GYRO ZERO BIAS ABOUT DIFFERENT TEMPERATURE

According to table

From the IEEE to the temperature drift of optical-fiber gyro the definition: change of temperature was an important factor affecting the precision of optical-fiber gyro zero bias[

L----gyro output, unit º/h.

L0----the zero bias output obtained from the first two minutes of sampling after the gyro was started, unit º/h.

T ---- gyro sensitive temperature, unit °C.

Δ T ---- Temperature gradient of gyro, unit °C.

dT/dt ---- The temperature change rate of gyro unit °C/s.

Ai, Bj and Cj ---- polynomial coefficients,

M, n -- the highest power of all temperature factors.

The coefficients Ai, Bj and Cj in model polynomial were fitted by regression analysis and least square method. The polynomial model can be written as:

Q was the order of the temperature drift model, and T was the temperature matrix, and N was the data number of gyro temperature drift.

The coefficients fitted at different temperatures were different. The coefficients of Ai, Bj and Ck satisfy the following relation in formula (

The coefficient Aij (i=1,2…q; j=0,1,2,3) was obtained by least square calculation for each gyro at different temperatures. Solidify the coefficients in the computer test software.

As long as the initial temperature T0 of the gyro was measured after the gyro was started, the coefficients in the model can be calculated according to formula (

The influence of temperature on zero bias was mainly shown in three aspects: temperature, temperature change rate and temperature gradient[

Using the data in Table

Polynomial fitting curve about the gyro zero bias caused by temperature

The influence about temperature to gyro zero bias

Gyro output by 2\4 order polynomial compensation while temperature transition

GYRO OUTPUT BY 1 TO 4 ORDER POLYNOMIAL COMPENSATION WHILE TEMPERATURE TRANSITION

From table

The relationship between the temperature gradient and the gyro zero bias was shown in figure

Relationship between temperature gradient and gyro zero bias

Based on temperature compensation, temperature gradient compensation was added on the zero bias, the zero bias standard deviation was shown in table

THE RESULT AFTER ADDING COMPENSATION BY TEMPERATURE GRADIENT

According to the date from table

In Figure

COMPENSATION RESULT AFTER TEMPERATURE TRANSITION\TEMPERATURE GRADIENT\TEMPERATURE TRANSITION RATE

Gyro output by 2\4 order polynomial compensation after temperature transition\temperature gradient\temperature transition rate

From table 5 and Figure

Temperature was one of the most important factors that affect the zero bias of optical-fiber gyro. The temperature characteristics about optical-fiber gyro has to be studied and zero bias caused by the temperature changes must be compensated if optical-fiber gyro can be used in the field of engineering application. Based on the analysis of the influence mechanism of optical-fiber gyros working principle and temperature influence to zero bias, temperature test of optical-fiber gyro was carried out, zero bias compensation method was studied, and the compensation effect was analyzed by experiment data. The experiment results show that the influence of temperature on the zero bias of optical-fiber gyro was effectively reduced by using multinomial fitting method, which were compensated by three aspects of temperature, temperature gradient and temperature change rate.