Coordinate transformation and target deviation calculation for roll-pitch seeker

The inconsistency between the definitions of the roll-pitch coordinate system and the azimuth-pitch coordinate system hinders the direct application of traditional control strategies to roll-pitch seeker. This paper establishes a coordinate transformation based on the coude optical path to address this issue and calculates the target deviation in the azimuth-pitch coordinate system. This resolves the discrepancy between the two coordinate systems and enables the decoupling of the roll-pitch seeker. Subsequently, a correlation analysis is conducted between the output errors of the coude optical coordinate transformation model and the input variables. Based on this analysis, a correction model is established to compensate for assembly errors, gimbal errors, and axis misalignments in the seeker simulator system. Finally, simulations are conducted to validate the accuracy of the target’s azimuth and pitch relative to the seeker simulator and to analyze the randomness of errors. The results show that the model yields small output errors under both static and dynamic conditions, while the proposed correction model further reduces the error magnitude and brings the distribution closer to normality.