This study considers intermittent maneuver based on line-of-sight rate bounding to improve target observability for passive homing guidance. Target observability is critical for the performance of the target tracking filter and indirectly affects the guidance accuracy. This paper derives an observability measure associated with the Fisher information matrix for the adaptive intermittent maneuver strategy proposed in the previous studies. Then, the key parameters of the adaptive intermittent strategy are identified and optimized to maximize the observability measure. Numerical simulations demonstrate that the tracking filter performance is significantly improved. It is also confirmed that the guidance accuracy of proportional navigation is also improved by employing the adaptive intermittent maneuver strategy.