# Reliability Analysis of Hybrid Laser INS Under Multi-Mode Failure Conditions
## 7 Conclusions  
This study analyzed the uncertainty of a novel hybrid laser inertial navigation system that fails during high-dynamics, long-duration operations. First, mechanical simulation models (rotational modulation structure with angular motion isolation and outer frame component) were established to analyze key components' mechanical properties under high overloads with different composites. Then, taking the deviation of the inertial navigation coordinate system from the virtual inertial group coordinate system under impact overload as the navigation failure criterion, a Kriging-based reliability analysis model for hybrid inertial navigation function failure was set up. Furthermore, considering the outer frame component's structural strength failure criterion under overload, a Kriging-based reliability analysis model for its structural failure was developed. Global sensitivity analysis (based on the Bayesian formula) and uncertainty analysis (based on Sobol sequence sampling) were used. Finally, experimental verification was conducted, and the following conclusions were drawn:  
Figure 26: (a). \(Z\)-direction impact input. (b). \(Z\)-direction impact table body response output. The Chinese character “\(\
exists\)” in the picture means time domain. 1. Modal analysis shows that structural components made of SiCp/Al composite have significantly higher dynamic frequencies than those made of ZL107 material, highlighting the boost in dynamic frequency with stiffer materials. Under 120 g, 11 ms half-sine impacts, SiCp/Al in the hybrid inertial navigation system deforms less, being less prone to plastic failure, more overload-resistant than ZL107, and ensuring better safety. 2. Bayesian-based global sensitivity analysis (sample size \(N\)1 = 5 \(\times\) 10\({}^{5}\)) indicates that inner frame thickness, inner frame material strength, and outer frame thickness most significantly impact the hybrid inertial navigation function's failure probability (sensitivities: =0.01657, =0.00873, =0.00818). Kriging-model-based, dual-random uncertainty analysis of the outer frame shows that its multi-mode failure probability follows an \"increase-then-decrease\" trend. SiCp/Al has a much lower failure probability than ZL107, confirming its high-overload deformation resistance and reliability, useful for hybrid inertial group reliability design. 3. Within the size envelope range, the optimal design parameters were selected to design and machine form each part. After assembling and debugging the entire machine, impact tests were conducted on the product in the X, Y, and Z directions. The tests showed that the laser gyroscope worked normally, the hybrid laser system function was normal, and the platform angular velocity change corresponding to each impact direction was less than 12 \"/s. The maximum angle change of the inner and outer frames was 0.107\({}^{\circ}\), indicating that the system structure can withstand large overloads and multiple levels of mechanical environments and has good environmental adaptability and reliability. 4. Within the field of the design of hybrid inertial navigation structures, this paper studies the optimization of material distribution and geometric dimensions through parametric design and analysis, significantly reducing stress concentration phenomena. Simultaneously using high-performance composite materials can improve the strength, stiffness, and fatigue life of the structure and better meet the design requirements for lightweight and compact product design. At the same time, this significantly improves the stability of the structure and reduces the impact of external large-scale mechanical environments on the navigation system. The proposed structure can provide a more stable installation reference surface for inertial navigation systems, significantly improving navigation accuracy, especially in long-term and high-dynamic environments. Therefore, high-strength and high elastic modulus materials should be prioritized to achieve better performance in high-overload and dynamic environments.