基于运动恢复结构(structure from motion,SFM)算法的地面影像定向通常没有考虑影像的位置姿态信息,影像定向结果在自由网坐标系,因此无法获取绝对坐标和真实尺度;利用地面摄影实时动态(real-time kinematic,RTK)技术可以获取地面影像...基于运动恢复结构(structure from motion,SFM)算法的地面影像定向通常没有考虑影像的位置姿态信息,影像定向结果在自由网坐标系,因此无法获取绝对坐标和真实尺度;利用地面摄影实时动态(real-time kinematic,RTK)技术可以获取地面影像的位置姿态信息,但是RTK和摄影测量的角度系统定义不同,RTK相位中心与影像投影中心存在偏差。针对这些问题,推导了利用RTK获取的GPS和角元素heading pitch roll(HPR)计算影像外方位元素的公式,提出地面摄影RTK辅助SFM算法的地面影像定向方法,在少量或者无需像控点条件下将SFM算法自由网的定向结果转换到绝对坐标系下,获得场景的真实坐标和尺度。实验结果表明,该转换公式正确,地面摄影RTK辅助SFM算法的影像定向方法可行。展开更多
The BeiDou global navigation satellite system(BDS-3)constellation deployment has been completed on June 23,2020,with a full constellation comprising 30 satellites.In this study,we present the performance assessment of...The BeiDou global navigation satellite system(BDS-3)constellation deployment has been completed on June 23,2020,with a full constellation comprising 30 satellites.In this study,we present the performance assessment of single-epoch Real-Time Kinematic(RTK)positioning with tightly combined BeiDou regional navigation satellite system(BDS-2)and BDS-3.We first investigate whether code and phase Differential Inter-System Biases(DISBs)exist between the legacy B1I/B3I signals of BDS-3/BDS-2.It is discovered that the DISBs are in fact about zero for the baselines with the same or different receiver types at their endpoints.These results imply that BDS-3 and BDS-2 are fully interoperable and can be regarded as one constellation without additional DISBs when the legacy B1I/B3I signals are used for precise relative positioning.Then we preliminarily evaluate the single-epoch short baseline RTK performance of tightly combined BDS-2 and the newly completed BDS-3.The performance is evaluated through ambiguity resolution success rate,ambiguity dilution of precision,as well as positioning accuracy in kinematic and static modes using the datasets collected in Wuhan.Experimental results demonstrate that the current BDS-3 only solutions can deliver comparable ambiguity resolution performance and much better positioning accuracy with respect to BDS-2 only solutions.Moreover,the RTK performance is much improved with tightly combined BDS-3/BDS-2,particularly in challenging or harsh conditions.The single-frequency single-epoch tightly combined BDS-3/BDS-2 solution could deliver an ambiguity resolution success rate of 96.9%even with an elevation cut-off angle of 40°,indicating that the tightly combined BDS-3/BDS-2 could achieve superior RTK positioning performance in the Asia-Pacific region.Meanwhile,the three-dimensional(East/North/Up)positioning accuracy of BDS-3 only solution(0.52 cm/0.39 cm/2.14 cm)in the kinematic test is significantly better than that of the BDS-2 only solution(0.85 cm/1.02 cm/3.01 cm)due to the better geometry of the current BDS-3 constellation.The tightly combined BDS-3/BDS-2 solution can provide the positioning accuracy of 0.52 cm,0.22 cm,and 1.80 cm,respectively.展开更多
基金the National Natural Science Foundation of China(Nos.41774031,41904035,91638203)Hubei Provincial Natural Science Foundation of China(No.2019CFB261)+1 种基金the National Science Fund for Distinguished Young Scholars(No.41825009)Key Laboratory of Geospace Environment and Geodesy,Ministry of Education,Wuhan University(No.19-01-06).
文摘The BeiDou global navigation satellite system(BDS-3)constellation deployment has been completed on June 23,2020,with a full constellation comprising 30 satellites.In this study,we present the performance assessment of single-epoch Real-Time Kinematic(RTK)positioning with tightly combined BeiDou regional navigation satellite system(BDS-2)and BDS-3.We first investigate whether code and phase Differential Inter-System Biases(DISBs)exist between the legacy B1I/B3I signals of BDS-3/BDS-2.It is discovered that the DISBs are in fact about zero for the baselines with the same or different receiver types at their endpoints.These results imply that BDS-3 and BDS-2 are fully interoperable and can be regarded as one constellation without additional DISBs when the legacy B1I/B3I signals are used for precise relative positioning.Then we preliminarily evaluate the single-epoch short baseline RTK performance of tightly combined BDS-2 and the newly completed BDS-3.The performance is evaluated through ambiguity resolution success rate,ambiguity dilution of precision,as well as positioning accuracy in kinematic and static modes using the datasets collected in Wuhan.Experimental results demonstrate that the current BDS-3 only solutions can deliver comparable ambiguity resolution performance and much better positioning accuracy with respect to BDS-2 only solutions.Moreover,the RTK performance is much improved with tightly combined BDS-3/BDS-2,particularly in challenging or harsh conditions.The single-frequency single-epoch tightly combined BDS-3/BDS-2 solution could deliver an ambiguity resolution success rate of 96.9%even with an elevation cut-off angle of 40°,indicating that the tightly combined BDS-3/BDS-2 could achieve superior RTK positioning performance in the Asia-Pacific region.Meanwhile,the three-dimensional(East/North/Up)positioning accuracy of BDS-3 only solution(0.52 cm/0.39 cm/2.14 cm)in the kinematic test is significantly better than that of the BDS-2 only solution(0.85 cm/1.02 cm/3.01 cm)due to the better geometry of the current BDS-3 constellation.The tightly combined BDS-3/BDS-2 solution can provide the positioning accuracy of 0.52 cm,0.22 cm,and 1.80 cm,respectively.
