全球定位系統(Global Position System, GPS)現在已廣泛的應用於軍事或是民間用導航系統上。在一般情形下長時間使用,訊號穩定度相當足夠。可是GPS最讓人詬病的就是其訊號很容易受到外在因素影響,如:天候、建築物等因素,導致訊號收訊不良而無法進行定位工作。 慣性導航系統(Inertial Navigation System, INS)並無上述之缺點,可是長時間使用,會因為積分誤差導致訊號準確度降低。而積分誤差的來源包括很多因素,其中主要的來源為所謂的輸出誤差,以及軸偏差因子等誤差來源。所以在使用INS前必須先進行校正動作以減少誤差。 而本篇論文主要之目的,就是利用卡曼濾波器(Kalman Filter)整合GPS以及INS,使系統在一般狀況下可得到更精確的結果;除此之外,GPS訊號脫鎖後,依然可以利用卡曼濾波器擷取INS量測值,推估出系統載具所在之實際位置,使系統可以繼續維持導航之任務。 本篇論文除了包含導航系統狀態方程式建立及計算外,還包括了慣性量測元件的校正與補償之方法與理論。
Global Position System (GPS) is broadly used in military or civil navigation devices. GPS can work for a long time and its output can still remain stable. But it is easily interfered by external factors such as weather, building and etc. Inertial Navigation System (INS) doesn’t have the above defects of GPS but its accuracy is reduced by integration errors. Integration errors come from many factors. The errors are mostly caused by output errors and axis misalignment factor. Therefore, calibration and compensation of output errors are required before apply INS. This paper contains state equations of system and the method theory of INS’s calibration and compensation. The purpose of this paper is to apply Kalman Filter to integrate GPS and INS such that the system can still calculate its position by INS’s signals even if lost GPS signals.