Infrared attitude measurement signal parameter estimation based on gradient zero-crossing method

Abstract

Prior to measuring the attitude of a projectile using contemporary infrared techniques, it is necessary to calibrate the output signal parameters of the infrared sensor. These measurements are influenced by factors such as the projectile’s flight path, surrounding vegetation, and geographical region. To address the issue that the calibrated infrared attitude signal parameters lack applicability for long-distance flights across varying regions and vegetation, a novel method for estimating infrared attitude measurement signal parameters has been developed. This method is based on the gradient zero-crossing method. Based on the gradient information derived from the infrared sensor, the extrema of the infrared signal can be converted into zero-crossing points. By utilizing the update of the maximum value within the nearest half-cycle as the time base, the maximum and minimum values of the infrared attitude measurement signal in the last nearest half-cycle are obtained through interpolation with an approximate uniform variable-speed model. Consequently, the model parameters of the attitude measurement signal, which are applicable to the current projectile flight environment, are estimated and updated. By changing the experimental environment, the feasibility of the infrared signal parameter estimation method for attitude measurement based on the gradient zero-crossing method proposed in this paper is verified. Compared with the calibration results in the same environment, the relative errors of amplitude and bias parameter estimation are respectively less than ±0.81% and ±0.11%. This proposed parameter estimation method addresses the issue of fixed calibration parameters in attitude measurement signals, thereby enhancing the versatility of the infrared attitude measurement method for projectiles.