针对海岛礁地形特点,采用高性能垂直起降电动多旋翼无人机(VTOL)开展基于POS辅助的海岛礁无控制点航测技术研究,分析基于POS辅助低空无人机航测系统的相关技术要求,为今后南海岛礁海岸带地形获取工作提供技术依据。通过实地试验开展了海岛礁测图试验与精度验证,采用搭载OEM POS系统的无人机低空航空摄影测量系统及基于CORS 基站的 POS 数据解算和基于 PPP 技术的 POS数据解算2种方法的处理结果并分析比较两者的精度指标,以论证实现海岛礁无控制测量作业的技术可行性。通过前期调研给出了典型搭载设备及无人机型号的建议,通过本次试验获取了试验区域高分辨率的数码影像,得到高精度试验区域1∶2 000数字线划图(DLG)测图成果,并提出了适用于南海海域岛礁测量的、基于POS辅助的海岛礁无控制点低空摄影测量的相关技术要求,以期形成海岛礁测图的行业作业技术规范。试验结果表明,该系统在无控制点情况下,基于MEMS POS辅助的无人机航测技术可满足海岛礁1∶2 000大比例尺海岛地形测绘精度要求。

In line with sea reef terrain characteristics, POS-aided low altitude photogrammetry of sea islands and reefs without Ground Control Points (GCP) was researched using VTOL (Vertical Take-Off and Landing) system. The technical requirements of POS-aided UAV low altitude photogrammetry were analyzed in the aim of offering technical basis for acquiring the terrain of coastal zone of South China Sea islands and reefs in future. The technical feasibility of photogrammetry of sea islands and reefs without GCP is demonstrated by verifying the accuracy of mapping through field test and comparing the accuracy indicators between POS data based on low altitude OEM POS-borne UAV photogrammetry system and CORS stations and POS data based on PPP technique. Based on previous investigations, suggestions on typical equipment and UAV specification were given. In the present test, the high resolution digital images of the test area and the 1:2000 digital line drawing (DLG) mapping result of high precision were obtained. Moreover, some technical requirements of low-altitude POS-aided photogrammetry for the survey of islands and reefs in the South China Sea are put forward in the purpose of forming technical specification for the mapping of islands and reefs. The test results validate that the POS-aided UAV photogrammetry technology meets the accuracy requirements of 1∶2000 large-scale hydrographic survey without GCP.