2021-5-28 1 Introduction1. Why stereo remote sensing ?2. Three means of stereo remote sensing 2.1 Spaceborne stereo optical imaging remote sensing 2.2 Spaceborne micirowave inSAR stereo remote sensing 2.2.1 Spaceborne SAR Remote Sensing Imaging 2.2.2 The principle of Spaceborne InSAR2.3 Spaceborne Lidar ranging remote sensing3 Stereo remote sensing application 3.1 Spaceborne stereo optical imaging remote sensing application3.2 Spaceborne micirowave inSAR stereo remote sensing3.2.1 the SAR stereo remote sensing application and data source3.2.2 InSAR Application in Stereo Remote Sensing3.3 Spaceborne Lidar ranging remote sensing4 Conclusion and the prospect of spaceborne Lidar stereo remote sensing application 3 n To acquires the 3D stereo image of the topography of the sceneThe image acquired will be different according to the range and angle relate to scene and imager. Human can observe the earth by all kinds of imager from satellite above hundreds of kilometers high, so Spaceborne ones have the high efficiency. Spaceborne stereo remote sensing is the means of the acquisition stereo information of the scene of the earth from the satellite.n Definition of Stereo remote sensing Broad senseTypes of the land overlays Attributes of buildingsSurface runoff Environments and AtmosphereStereo space scale informationandOther attibutes can be estimated by spectral,laser or microwave remote sensing waysNarrow sense Geographic Latitude LongitudeHeightStereo space scale informationDefinition of Stereo remote sensing 5 nSpaceborne stereo optical imaging remote sensing n Spaceborne microwave InSAR stereo remote sensing nSpaceborne Lidar ranging remote sensing 6 n Principle imaging from satellite using stereo imaging camera Stereo 3D information are from at least two image from appropriate observation Anglen The present optical imager on orbit (table 1) 7 Satellite Droid Launch Time Sensor type Swath Product resolution Recurrence cycleSPOT5: HRS France 2002.5.4 Tw o - l i n e -array 150km Along track： 5m；across track 10m；altimetry precision： 10-15m 5D（ 26D）CartoSat-1 Indian 2005.5.5 Tw o - l i n e -array 26Km Locating precision:10m;altimetry precision： 5m 5DALOS Japan 2006.1.24 Three-line-array 70Km Locating precision:1m,GSD:2.5m 46dWorldView-2 USA 2009.10.6 Single-array 16.4Km Locating precision:8.5-10.7m(no condition point),2m(under condition point); GSD:0.46m(panchromatic),1.8m(multi-spectral);altimetry precision： 0.3m(under condition point) 1.1d(under resolution higher than 1m );3.7D(Sidesway:20deg,0.52m)GeoEye-1 USA 2008.9.6 Single-array 15.2Km Locating precision:5m(no condition point),2m(under condition point);GSD:0.41m(panchromatic),1.65m(multi-spectral)altimetry precision： 2m(under condition point) 3.7D(Sidesway:20deg,0.52m) 8 n The synthetic aperture radar(SAR)In the late 1970s spaceborne imaging radars began to play an important role in remote sensing, first for investigation of planetary surfaces, and later with the NASA satellite SEASAT, which was launched in 1978, for Earth observation (Allan 1983, Elachi 1991,Raney 1982b). The synthetic aperture radar(SAR) is able to reliably map the Earths surface and acquire information about its physical properties, such as topography, morphology, roughness and the dielectric characteristics of the backscattering layer. As the spaceborne SAR systems operate in the microwave (cm to dm wavelength) regime of the spectrum and provide their own illumination they can acquire information globally and almost independently of meteorological conditions and sun illumination. 9 n The principle of Spaceborne InSAR Fig.1 Principle Diagram of InSAR The Pixels of the image acquired by spacebrone SAR system contain information of the intensity of the backscattered radar wave from the ground scene,as well as the range(from the imager to the scene) concerned phase information.The interferogram can be obtained by subtraction of two radar phase images of certain scene,which imaged from slightly different position or time. By the beneficial of high sensitivity to phase difference features, we can find the elevation information of the imaging scenen Some of the present SAR on orbit (table 2) Satellite Droit Launch time/Ended time Polarization mode Swath width S p a t i a l Resolution Earth topics Recurrence cycle(day)ERS1 ESA 1991/2000.3.10 VV 100km 10m x 5m Ocean surface temperature and wind fields 3/126ERS2 ESA 1995/2011.9.5 VV 250-350km 10m x 5m ER1S1+atmospheric zone monitoring 3/24ENVISAT ASAR ESA 2002/2012.4.8 VV, HH,VV/HH, HV/HH, or VH/VV 56-100km;400 x 400km;10kmx5km; 5kmx5km 30m ;150m ;1000m . Landscape Topography , Snow and Ice ,Ocean Currents and Topography 2/35ALOS PALSAR JAXA 2006.1.12/2011.6.12 V V, H H , V V / H H , HV/HH, or VH/VV 40 - 70km;250 -350km;20 - 65km 7 - 44m,14 to 88m,100m Geological Survey 2/46TerraSAR-X German 2010.6/- V V, H H , V V / H H , HV/HH, or VH/VV 5 - 10km (width) x 5km (length);10km x 10km ;30km x 50km ;100km x 150km . 1m ; 2m ;3m; ;18.5m ; 1,650 km commercial users around the globe 2.5 COSMO-Skymed ASI COSMO 1: 2007.6.8/-; COSMO 2: 2007.12.9-/;C O S M O 3 : 2008.10.25/-;COSMO 4: 2011.11.6/- 10km x 10km;40km x 40km;30km x 30km;100km x 100km; 1m;3m;15m;30m100m global Earth observation 16 Table2 Some of the characteristics of spaceborne SAR 11 n 3.1 Spaceborne stereo optical imaging remote sensing applicationn 3.2 Spaceborne micirowave inSAR stereo remote sensingn 3.3 Spaceborne Lidar ranging remote sensing 12 . Stereo remote sensing data is applied to generate a certain precision of the topographic map, or the existing topographic map revision.Data quality directly affect the mapping accuracy of remote sensing dataSatellite images suppliers can provide the data according to the accuracy requirements,which can be have different costs and barriers to purchase. The useable satellite stereo images must contains at least two the image data of the corresponding navigation and attitude data, so that it can be processed based on photogrammetry theory to recover the stereo feature of the target scene; However, the optical remote sensing imaging is unable to be operate effectively in all-weather condition such as rainy,and has no sensing ability in the night without sunlight illumination(to visible light sensor) . 13 InSAR Application in Stereo Remote Sensingn Three types of SAR interferometers and its application 14 The main application are surveying and mapping, earth science, global atmosphere, the moon, asteroids and Mar decteting, on-orbit service, space station service etc.Table 4 Several Spaceborne Lidar payloadsClementine MOLA-2 NRL GLASOrbit height 640km 400km 50km 600kmLaunch year 1996.12 1996.11.7 1994.1.25 2003.1.13Planet detected Moon Mars Rros asteroid Polar ice capsVertical resolution 40m 1m 0 32 0.15m（ 冰 、 陸地 ）Horizontal resolution 100m 300（ along track） ,4km(across track) 500m 170mIt can be seen that the measurement precision of height of spaceborne Lidar is much higher than other spaceborne altimeter mode referred to before. 15 .uLidar can measure the height of the global surface directly;uBoth SAR remote sensing imaging and optical remote sensing imaging must use at least two different images of a scene,at the same time it requires complex solutions to get the surface height information;uFor the height measuring precision,the elevation Lidar measured is in the highest precision contrast to other current technology;uCompared with airborne Lidar, spaceborne Lidar has higher altitude, wider view observation, and effective to accomplish high precision observation outside of a nation without control points ,so it has a great significance in national defense. uAlthough Lidar can directly measure the height of the corresponding scene, but due to the nature of the point cloud raw data type , it must processed through a certain processing stream with the help of images of other type to reconstruct the stereo scene which contains both surface height information and the texture information. Therefore, the techniques of processing of height cloud data of spaceborne Lidar processed with other high resolution images to reconstruct stereo model of the the ground object is an important research direction of the remote sensing application. 2021-5-28 17Thank you！