## 5 Experimental Analysis of a Highly Dynamical Scene
### Experimental Results and Analysis  
Since the performance of each tracking channel is the same and the satellite signal index is consistent, the results of one of the satellite channels is selected here in order to analyze the results. The comparison results of DLB-RACKF, DLB-CKF, and DLB-UKF tracking errors are shown in Figures 3 and 4. Figures 5 and 6 show the comparison results of DLB-RACKF, DLB-AHCKF, and DLB-STCKF. Table 1 shows the RMS statistics of the tracking error of the five methods in each period. The runtime performance of five filters is summarized in Table 2.  
Figures 3 and 4 are essentially based on the comparison results of tracking errors among three different algorithms with the same coupling structure. From Figures 3 and 4 and Table 1, we can see that the accuracy of DLB-CKF is slightly better than that of DLB-UKF in tracking error accuracy. The precision of DLB-RACKF is better than that of DLB-CKF and DLB-UKF. In the tracking stability of the algorithm, due to the lack of adaptive adjustment performance, both DLB-CKF and DLB-UKF show the condition of changing errors when the measurement noise increases and the vehicle moves with high maneuverability, such as when the 5 th second measurement noise parameter continues to expand, the phase frequency and code tracking error of DLB-CKF and DLB-UKF immediately change. Eventually it will lead to a decline in the precision of navigation. When the noise of the 10 th second measurement returns to normal, the PB-KF-UTC does not return to the initial accuracy immediately, but after about 1000 ms, it gradually converges to the normal precision range. In the 20 th second, when the carrier performs variable acceleration motion in the range of about 10 g/s, the tracking error of PB-KF-UTC suddenly increases. This is due to the fact that the dynamic model no longer meets the basic situation of the actual motion, there is a large deviation, and when the variable acceleration motion is finished, the error of DLB-CKF and DLB-UKF is converged to the normal precision range again, with the process lasting for 2 s to 3 s. In the same way, in the 40 th second, when the carrier  
Figure 4: Comparison of the code phase tracking error among DLB-UKF, DLB-CKF, and DLB-RACKF. Figure 5: Comparison of code phase tracking error among DLB-AHCKF and DLB-RACKF. performs variable acceleration motion at the range of about 10 g/s, the tracking error of DLB-CKF and DLB-UKF changes again, but because the maneuverability is too large, with the result that it is difficult for PB-KF-UTC to converge again when the motion of variable acceleration is finished, the phenomenon of divergence appears. However, in the whole tracking process, DLB-RACKF has maintained a good tracking accuracy and stability. The DLB-CKF converges gradually after the end of the variable acceleration motion, which ensures continuous tracking, which indicates that the stability of CKF is better than that of UKF. Compared with DLB-CKF and DLB-UKF, DLB-RACKF is relatively stable in the whole tracking process. When the measurement noise is abnormal and the dynamic model error increases due to the high maneuvering motion of the carrier, the DLB-RACKF can maintain better adaptive regulation performance. Its tracking stability is much better than that of DLB-CKF and DLB-UKF. Figures 5 and 6 compare the tracking errors among the improved CKF algorithms with the same adaptive adjustment function. As shown in Figure 5 and Table 1, DLB-AHCKF and DLB-RACKF exhibit good adaptive performance when the kinematic model is accurate and the measurement error increases. Since the 5 th second of measurement noise continues to increase, the DLB-AHCKF accurately estimates the noise changes after about 800 ms, and adjusts the algorithm to the normal range of precision. In the 20 th and 40 th seconds, when the carrier is highly maneuvering for two times, the dynamic model is no longer accurate, and the tracking error of DLB-AHCKF increases suddenly. The change rule is similar to that of DLB-CKF.