To enhance the optimization performance of matched filter and further improve line of sight (LOS) stability of platform in inertial space, the proposed matched filter algorithm is conducted by adjusting matched filter coefficients of firstorder low pass filter utilizing the regional search method based on invariance principle. The coefficients of the fraction molecule and denominator of proposed regional search algorithm are altered instead of denominator coefficients only being modified. Simulations are performed to verify the validity of inside factors performed with stabilization control model and quartz rate sensor (QRS) mathematical model. The stable angular error is sharply alleviated, so the decoupling accuracy of airborne semistrapdown inertially stabilized platform is largely promoted. The optimization matched filter can effectively increase stability of LOS in inertial space.
Photoelectric sensor is a device of great importance for detecting and tracking targets in semistrapdown stabilized platform [
Scholars put forward some opinions on increasing stability. In 1993, strapdown platform model was investigated and decoupling results of QRS and FOG sensor were obtained in [
Previous matched filter researches are just mostly focused on the change of the denominator coefficient, while the molecular coefficient of the firstorder lowpass filter is a fixed parameter. However, to further improve the optimization performance, the proposed regional search algorithm dynamically limits the search area and reduces the search complexity of the algorithm in time and space, so the operation efficiency of the algorithm is greatly improved.
The overall paper is organized as follows: Section
The twoaxis and twoframe miniature semistrapdown stabilization platform has its advantages, which makes it become a great tool for the integration of investigation and combat. In [
Control model of semistrapdown platform.
In this system,
When
The disturbance of body to the LOS is eliminated when
The closedloop structure of stable rate is simplified as shown in Figure
The closedloop structure of stable rate.
In order to make
The related data of the QRS model of matched filter algorithm is based on [
The related data of the QRS model.
Dynamic component  Expression 

Compensation 

Inertia  0.05 
Differentiator 

Gyro 

Converter 

The transfer function after matched filter is
The objective function can be established by the nonlinear constrained optimization algorithm of mechanical optimization design scheme [
The flowchart of Algorithm 2 is indicated in Figure
Flowchart of Algorithm 2.
Algorithm structure diagram of the first step.
The better simulation effect of
Algorithm structure diagram of the second step.
The last result of Figure
Algorithm structure diagram of the third step.
In order to better explain the validity of the algorithm, taking the closedloop stability control system into consideration, the simulation model in [
Optimization model of inertial stabilization platform.
Considering the speed of reaching the steady state of the system, the step response is presented in Figure
Step response time of three steps.
The time of reaching the steady state is very principal for engineering application. It is clear that the
The matching effect of the matched filter plays an indispensable role in engineering. It is helpful even if there is a little improvement, as is shown in Figure
Comparison of decoupling accuracy of four groups’ matched filter.
The coefficients
The related data of flying bodies angular velocity motion is given based on [
The input rate of flying bodies.
Environment 



Deg/s  Hz  
Free flight number 1  130  5 
Free flight number 2  260  2.5 
Free flight number 3  430  5 
Captive carry  315  50 
As shown in Figure
The platform rate before matched filter and after matched filter.
Simulation results from Figure
The stable angle errors of the four groups’ matched filter of Figure
Stable angle error under different matched filter.
Stable angle error is obviously distinct using dissimilar matched filter from Figure
The angular velocity of the semistrapdown stabilized platform is obtained by rate gyroscope and related calculation from Figure
In Figure
Stable angular error.
Measurement rate is matched by firstorder low pass filter based on invariance principle. Simulations show that the angular rate of the platform is lessened by
The measurement noise of sensor has huge influence on the stable error. The stability of the angle error is decreased by nearly
The stability of LOS can be strengthened based on the above simulation results. So it provides theoretical foundations for designing and optimization of the microstable platform, which has a strong guiding significance in engineering.
The authors declare that there is no conflict of interests regarding the publication of this paper.