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测绘一般包括基础测绘、详细测绘和精确测绘三类。由于多波束激光测绘卫星的激光特性使得它能够用于精确高程测绘,并辅助其他测绘数据。它是测绘体系中的重要组成部分,可与其他测绘数据进行融合,提高测绘效能。
精确测绘相比于基础测绘、详细测绘,在测绘技术指标体系方面对高程提出了更高的要求,如表1所示。绘制1∶10 000和1∶5 000比例尺地形图,高程指标参数从3 m提高到1 m。由于激光波长很短,方向性强,频率高,波束发散角小,受外界干扰影响小,激光多波束测绘卫星相对其他测绘手段较易实现地形的精确测绘,平面精度优于2.5 m,高程精度优于0.5 m,满足1∶5 000的测图要求。
表 1 基础测绘、详细测绘、精确测绘对比
Table 1. Comparison of basic surveying and mapping, detailed surveying and mapping and accurate surveying and mapping
Capability type Basic surveying and mapping Detailed mapping Accurate mapping Detection range Global Key areas Target area Uncontrolled ground target location/m Plane ≤50 ≤25 ≤10/3 Altitude ≤6 m ≤3 ≤1 Ground pixel resolution/m 3-5 ≤2 0.6-1/0.3-0.5 Topographic map scale 1∶50 000 1∶2.500 00 1∶10 000/1∶5 000 DEM grid/m 50/25 25/12.5 10/5 or 2 Gravity field accuracy (resolution) 2/3 mGal (160 km) 2/3 mGal (80 km) 3 mGal (10 km) Magnetic field accuracy/nT 3-5 2 2 Update cycle of geographic information Needed 1-3 a Needed 激光多波束测绘卫星能形成1∶50 000以上,甚至全球高精度高程控制点,并与侦察卫星图像数据融合,使其图像定位精度可产生质的飞跃,可大幅提升我国在轨数十颗光学卫星、SAR卫星的平面定位精度和高程精度,从而增强侦察卫星测绘能力,从体系规划上实现侦测一体[4-9]。
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地球的表面是动态,地表拥有水文的、生物的进程,上升、侵蚀和沉积作为调节是相互影响的。表面地形影响气流、沉降模式以及控制水和泥流分布。结果,地形控制泥流深度、泥流水分和植被空间模式。而且,它影响自然灾害的分布,如山崩、洪水和地震。通过分析高分辨率地形数据可理解哪一个地壳力释放改变了地球表面和地质构造。时间序列的高精度地形数据可用来观察地球表面通过山崩、洪水、侵蚀、大地震、海啸的重构。直到最近,粗糙的地形测绘分辨率是理解改变地球表面的力和动态过程的一个主要的障碍。
依赖精确的地形数据可预测山体滑坡、洪水、海啸迅速增大、火山碎屑流和泥石流发生的时间和地点。利用全球30~90 m分辨率,10 m垂直精度的有效地形数据对这些预测是不够的。全球高分辨率地形数据也将推进这些风险评估的科学性。精确的地形测量将有助于发现活动的断层(包括隐伏断层),因此有利于更好地评估地震灾害。时间序列的高精度地形数据将有助于测量世界范围内的地表土层流失,有助于判定大地震的滑动区域。激光多波束测绘也将产生全球森林的林段结构数据,因此将提升火灾风险评估达到一个空前的水平[4-9]。
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近海浅海地形探测主要由两部分组成:沿岸地形测量和水深测量。海岸地形包括海岸线以上陆地地形、潮间带滩涂地形和浅海水下地形三部分。当前近海岸水深及浅海地形测量主要采用三种模式,海岸线以上部分以地形图转绘为主,海岸线至零米线(潮间带)区域采用人工实地测量与船载水深测量相结合的测量模式,零米线以下(浅海)区域采用单波束或多波束水深测量技术。近年来,机载激光测深技术发展很快,有效弥补了以舰船为平台的传统声学测量方法在浅海作业存在的缺陷,国内在应用刚刚起步,但对境外区域无能为力。
当前近海岸水深及浅海地形测量所采用的技术手段特点及存在的问题是:(1)人工实地测量作业方式劳动强度大,作业效率低,条件艰苦,环境危险;(2)目前采用的技术手段只适用于境内海岸带和测量人员可到达区域的测绘,对于境外乃至全球或境内测量人员无法到达的区域无法施测;(3)干出滩测量以半潮线为界,分别采用人工实地测量和船载声纳水深测量,然后将两种测量成果拼接。特殊的地理环境造成两种作业方式均受到严重制约,无法发挥其技术特点,使滩涂测量成为海洋测绘作业难度最大、技术能力最薄弱的环节,形成技术瓶颈;(4)受海潮作用和人为开发建设,沿岸地形动态变化,影响海图的现势性要求,受制于数据源匮乏、高精度测量技术手段有限,对境外海图编绘存在数据盲区,海图要素特别是高程信息的标注极为困难,使得在海洋生态环境监测、资源考察等过程中船舶航行航路规划受到制约[4-9]。
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蓝绿波段激光可穿透海洋次表层水体,利用激光遥感技术可以获取海洋光学参数剖面、海水温度剖面、浅海水深等信息,是目前星载遥感器实现海洋次表层剖面探测的唯一手段,与被动遥感相结合可以构成地球三维立体观测能力。星载激光雷达也可对上混合层叶绿素、悬移质等要素进行探测,能在三维空间尺度上监测浮游植物,并提供一种亚-中尺度生物-物理耦合进行系统观察的方法,这对全球碳循环以及上层海洋动力过程的理解具有重要意义,增强对海洋信息的获取能力[1, 10-12]。
Research on the development of detection satellite technology in the novel multi-beam land and ocean lidar
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摘要: 从国家未来战略需求出发,对发展陆海激光雷达需求进行了分析,介绍了陆海激光雷达的特点和国内外星载激光雷达卫星发展的现状,提出了未来星载陆海激光雷达卫星的发展方向,以及在轨预期数据的应用产品,给出了星载海洋激光雷达关键技术及解决途径,阐述了“十四五期间”陆海激光雷达的应用前景。Abstract: Started with needs of the national strategy, the necessity of China’s oceanographic lidar developing was analyzed, the characteristics of the oceanographic lidar and domestic and overseas’ development of the spaceborne lidar’s were summarized, the future spaceborne ocean lidar’s development direction was put forward and expected on-orbit data application products was proposed. The key technology and solution of the spaceborne ocean lidar were discussed, the application prospect of developing the marine lidar was given during the 14th five year plan.
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Key words:
- ocean optics /
- spaceborne lidar /
- ocean remote sensing /
- laser altimetry /
- surveying and mapping
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表 1 基础测绘、详细测绘、精确测绘对比
Table 1. Comparison of basic surveying and mapping, detailed surveying and mapping and accurate surveying and mapping
Capability type Basic surveying and mapping Detailed mapping Accurate mapping Detection range Global Key areas Target area Uncontrolled ground target location/m Plane ≤50 ≤25 ≤10/3 Altitude ≤6 m ≤3 ≤1 Ground pixel resolution/m 3-5 ≤2 0.6-1/0.3-0.5 Topographic map scale 1∶50 000 1∶2.500 00 1∶10 000/1∶5 000 DEM grid/m 50/25 25/12.5 10/5 or 2 Gravity field accuracy (resolution) 2/3 mGal (160 km) 2/3 mGal (80 km) 3 mGal (10 km) Magnetic field accuracy/nT 3-5 2 2 Update cycle of geographic information Needed 1-3 a Needed -
[1] Zhang Yang, Huang Weidong, Dong Changzhe, et al. Research on the development of the detection satellite technology in oceanographic lidar [J]. Infrared and Laser Engineering, 2020, 49(11): 20201045. (in Chinese) [2] Ralph Dubayah, James Bryan Blair, Scott Goetz, et al. The global ecosystem dynamics investigation: high-resolution laser ranging of the earth’s forests and topography [J]. Science of Remote Sensing, 2020, 1: 100002. doi: 10.1016/j.srs.2020.100002 [3] Peter Potapov, Xinyuan Li. Andres Hernandez-Serna, et al. Mapping global forest canopy height through integration of GEDI and landsat data [J]. Remote Sensing of Environment, 2021, 253: 112165. doi: 10.1016/j.rse.2020.112165 [4] Tan Xinming, Li Guoyuan. Thoughts about land and sea satellite laser altimetry [J]. Aerospace Shanghai, 2019, 36(3): 15-19. (in Chinese) [5] Quan Xuefeng, Tang Xinming, Li Guoyuan, et al. Application and prospect of satellite laser altimetry data in polar region [J]. Geomatics & Spatial Information Technology, 2019, 42(10): 19-24. (in Chinese) [6] Tang Xinming, Cong Nan. Present situation and development of surveying and mapping satellites in China [J]. Space International, 2011(2): 40-44. (in Chinese) doi: 10.3969/j.issn.1672-1586.2011.04.009 [7] Tang Xinming, Xie Junfeng, Zhang Guo. Development and status of mapping satellite technology [J]. Spacecraft Recovery & Remote Sensing, 2012, 33(3): 17-24. (in Chinese) doi: 10.3969/j.issn.1009-8518.2012.03.005 [8] Tang Xinming, Gao Xiaoming. The twelfth five-year development strategy research of mapping satallite and satallite surveying of China [J]. Bulletin of Surveying and Mapping, 2012, 10: 1-4. (in Chinese) [9] Li Manchun, Liu Yaolin, Tang Xinming, et al. Discussion on remote sensing monitoring for typical elements of physical geographic national condition [J]. Geomatics World, 2015, 22(5): 8-13. (in Chinese) doi: 10.3969/j.issn.1672-1586.2015.05.002 [10] He Yan, Hu Shanjiang, Chen Weibiao, et al. Research progress of domestic airborne dual-frequency LiDAR detection technology [J]. Laser & Optoelectronics Progress, 2018, 55(8): 082801. (in Chinese) [11] Hu Shanjiang, He Yan, Chen Weibiao, et al. Design of airborne dual-frequency laser radar systemy [J]. Infrared and Laser Engineering, 2018, 47(9): 0930001. (in Chinese) doi: 10.3788/IRLA201847.0930001 [12] Xu Peituo, Tao Yuting, Liu Zhipeng, et al. Comparison of oceanic lidar experiments and simulation results [J]. Infrared and Laser Engineering, 2020, 49(2): 0203007. (in Chinese) doi: 10.3788/IRLA202049.0203007 [13] Quan Xuefeng, Tang Xinming, Gao Xiaoming, et al. Application and prospect of satellite laser altimetry datain polar region [J]. Journal of Remote Sensing, 2019, 42(10): 15-20. (in Chinese) doi: 10.3969/j.issn.1672-5867.2019.10.005 [14] Hu Liuru, Tang Xinming, Li Guoyuan, et al. Quality assessment and accuracy optimization of DSM using GLAS laser altimetry data [J]. Journal of Astronautics, 2019, 11(11): 39-43. (in Chinese) [15] Xie Dongping, Li Guoyuan, Tang Xinming. U.S. GEDI space-based laser altimetry system and its application [J]. Space International, 2018, 12: 40-44. (in Chinese) doi: 10.3969/j.issn.1009-2366.2018.08.007 [16] Li Guoyuan, Tang Xinming. Analysis and validation of ZY-3 02 satellite laser altimetry data [J]. Journal of Remote Sensing, 2017, 46(12): 1939-1949. (in Chinese) doi: 10.11947/j.AGCS.2017.20170174 [17] 唐新明, 常晓涛, 李国元. 实现“一星多用”, 保障地理信息安全—资源三号测绘卫星影像应用综述[J]. 卫星应用, 2014(6): 15-20. [18] 晓曲. 高分七号卫星[J]. 卫星应用, 2019(11): 78. [19] Li Kaipeng, He Yan, Ma Jian, et al. A dual-wavelength ocean lidar for vertical profiling of oceanic backscatter and attenuation [J]. Remote Sensing, 2020, 12(17): 1-20. [20] Chen Shuguo, Xue Cheng, Zhang Tinglu, et al. Analysis of the optimal wavelength for oceanographic lidar at the global scale based on the inherent optical properties of water [J]. Remote Sensing, 2019, 11: 2705. doi: 10.3390/rs11222705 [21] Li Hongpeng, Li Guoyuan, Cai Zhijian, et al. Full-waveform LiDAR echo decomposition method Journal of Remote Sensing [J]. Journal of Remote Sensing, 2019, 23(1): 89-98. (in Chinese) [22] Quan Xuefeng, Tang Xinming, Li Guoyuan, et al. Land cover classification application of satellite laser altimetry data: A case study in Beijing, China [J]. Remote Sensing Information, 2019, 34(6): 6-11. (in Chinese) doi: 10.3969/j.issn.1000-3177.2019.06.002