scholarly journals A NOVEL PROPOSAL OF GAOFEN-3 SATELLITE CONSTELLATION FOR MULTI-APPLICATIONS

2017 ◽  
Vol XLII-2/W7 ◽  
pp. 635-639 ◽  
Author(s):  
X. Qiu ◽  
C. Ding ◽  
B. Lei ◽  
B. Han ◽  
F. Li
Keyword(s):  
Target Identification ◽  
Control Points ◽  
Disaster Reduction ◽  
Satellite Constellation ◽  
Ground Control Points ◽  
The Earth ◽  
Differential Interferometry ◽  
System Requirements ◽  
Ocean Monitoring ◽  
Along Track

Gaofen-3 is the first C-band fully polarimetric SAR satellite in China, which is widely used in various fields such as ocean monitoring, disaster reduction and so on. In this paper, a new satellite constellation is proposed based on the orbit of Gaofen-3 satellite. The constellation includes Gaofen-3 and other two duplicates. It is able to do repeat-pass interferometry, repeat-pass differential interferometry, along-track interferometry and stereo measurement. With these abilities, it can generate the earth DEM without ground control points and have better performance in moving target identification and monitoring. The performance and the system requirements are analysed, which provides a good reference for the design of spaceborne SAR constellation.

scholarly journals A Fast, Three-Dimensional, Indirect Geolocation Method Using IAGM and DSM Data without GCPs for Spaceborne SAR Images

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5062
Author(s):  
Liu ◽  
Xiao
Keyword(s):  
Corner Point ◽  
Three Dimensional ◽  
Surface Model ◽  
Control Points ◽  
Sar Image ◽  
Sar Images ◽  
Ground Control Points ◽  
The Earth ◽  
Proportional Relationship ◽  
Geolocation Accuracy

To determine the geolocation of a pixel for spaceborne synthetic aperture radar (SAR) images, traditional indirect geolocation methods can cause great computational complexity. In this paper, a fast, three-dimensional, indirect geolocation method without ground control points (GCPs) is presented. First, the Range-Doppler (RD) geolocation model with all the equations in the Earth-centered rotating (ECR) coordinate system is introduced. By using an iterative analytical geolocation method (IAGM), the corner point locations of a quadrangle SAR image on the Earth’s surface are obtained. Then, a three-dimensional (3D) grid can be built by utilizing the digital surface model (DSM) data in this quadrangle. Through the proportional relationship for every pixel in the 3D grid, the azimuth time can be estimated, which is the key to decreasing the calculation time of the Doppler centroid. The results show that the proposed method is about 12 times faster than the traditional method, and that it maintains geolocation accuracy. After acquiring the precise azimuth time, it is easy to obtain the range location. Therefore, the spaceborne SAR image can be geolocated to the Earth surface precisely based on the high-resolution DSM data.

scholarly journals REAL-TIME ON-ORBIT CALIBRATION OF ANGLES BETWEEN STAR SENSOR AND EARTH OBSERVATION CAMERA FOR OPTICAL SURVEYING AND MAPPING SATELLITES

2019 ◽  
Vol IV-2/W5 ◽  
pp. 583-588
Author(s):  
W. Liu ◽  
H. Wang ◽  
W. Jiang ◽  
F. Qian ◽  
L. Zhu
Keyword(s):  
Real Time ◽  
Optical Axis ◽  
Earth Observation ◽  
Star Sensor ◽  
Control Points ◽  
Angle Variation ◽  
Attitude Stability ◽  
Ground Control Points ◽  
The Earth ◽  
Calibration Time

<p><strong>Abstract.</strong> On space remote sensing stereo mapping field, the angle variation between the star sensor’s optical axis and the earth observation camera’s optical axis on-orbit affects the positioning accuracy, when optical mapping is without ground control points (GCPs). This work analyses the formation factors and elimination methods for both the star sensor’s error and the angles error between the star sensor’s optical axis and the earth observation camera’s optical axis. Based on that, to improve the low attitude stability and long calibration time necessary of current satellite cameras, a method is then proposed for real-time on-orbit calibration of the angles between star sensor’s optical axis and the earth observation camera’s optical axis based on the principle of auto-collimation. This method is experimentally verified to realize real-time on-orbit autonomous calibration of the angles between the star sensor’s optical axis and the earth observation camera’s optical axis.</p>

Boresight Calibration of Airborne LiDAR System Without Ground Control Points

2012 ◽  
Vol 9 (1) ◽  
pp. 85-89 ◽  
Author(s):  
Chen Siying ◽  
Ma Hongchao ◽  
Zhang Yinchao ◽  
Zhong Liang ◽  
Xu Jixian ◽  
...  
Keyword(s):  
Airborne Lidar ◽  
Ground Control ◽  
Control Points ◽  
Lidar System ◽  
Ground Control Points

scholarly journals Accuracy of 3D Landscape Reconstruction without Ground Control Points Using Different UAS Platforms

Drones ◽  
2020 ◽  
Vol 4 (2) ◽  
pp. 13 ◽  
Author(s):  
Margaret Kalacska ◽  
Oliver Lucanus ◽  
J. Pablo Arroyo-Mora ◽  
Étienne Laliberté ◽  
Kathryn Elmer ◽  
...  
Keyword(s):  
Low Cost ◽  
Ground Control ◽  
Unmanned Aerial Systems ◽  
Control Points ◽  
Model Errors ◽  
Positional Accuracy ◽  
Ground Control Points ◽  
Digital Elevation ◽  
High Level ◽  
Aerial Systems

The rapid increase of low-cost consumer-grade to enterprise-level unmanned aerial systems (UASs) has resulted in the exponential use of these systems in many applications. Structure from motion with multiview stereo (SfM-MVS) photogrammetry is now the baseline for the development of orthoimages and 3D surfaces (e.g., digital elevation models). The horizontal and vertical positional accuracies (x, y and z) of these products in general, rely heavily on the use of ground control points (GCPs). However, for many applications, the use of GCPs is not possible. Here we tested 14 UASs to assess the positional and within-model accuracy of SfM-MVS reconstructions of low-relief landscapes without GCPs ranging from consumer to enterprise-grade vertical takeoff and landing (VTOL) platforms. We found that high positional accuracy is not necessarily related to the platform cost or grade, rather the most important aspect is the use of post-processing kinetic (PPK) or real-time kinetic (RTK) solutions for geotagging the photographs. SfM-MVS products generated from UAS with onboard geotagging, regardless of grade, results in greater positional accuracies and lower within-model errors. We conclude that where repeatability and adherence to a high level of accuracy are needed, only RTK and PPK systems should be used without GCPs.

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