本文旨就尋標器離軸角先天條件的限制, 而使用純比例導引律並配合保持離軸角(Off-borsight)為定值的方法(偏角追逐法), 來解決尋標器追蹤迴路無法穩定追蹤的困擾, 並探討此方法對飛彈性能之影響。結果經由數值分析驗證與理論相符合, 確實可以在離軸角限制條件下命中目標, 相對缺點為需要花較多能量與時間。 The purpose of this paper is to develop and investigate the pure proportional navigation missile guidance law under the constraint of off-boresight angle, which usually occurs in a seeker tracking loop. Numerical examples show that proposed guidance law provides a strategy to accommodate the above-mentioned constraint at the cost of consuming more energy and flight time.