Abstract
The Gaofen-7 (GF-7) satellite uses a two-beam laser altimetry system in which each beam is equipped with a laser footprint camera (LFC) to provide geometric processing of the laser footprint images that assist in optical image stereo mapping. Because of the violent vibrations during launch and the difference in the environment before and after entering orbit, the key parameters for geometric processing of the laser footprint images may change, which will cause large geolocation errors. Therefore, it is essential to carry out on-orbit calibration and validation for the laser footprint cameras. This study first constructs a rigorous geometric positioning model for the LFC of the GF-7 satellite and analyses various error sources that affect the geometric positioning accuracy of laser footprint images. Then, a comprehensive calibration method, which effectively eliminates the distortion of the LFC optical system, and the positioning error caused by the long-period jitter of the satellite platform, is proposed based on the multi-scene images combined with image simulation. The proposed method can effectively eliminate various errors that affect the geometric positioning accuracy of the GF-7 laser footprint image. The internal geometric positioning accuracy of the calibrated LFC is better than 0.7 pixels, and the absolute geometric positioning accuracy is within 6.0 m after using precise post-processing orbital and attitude data. Our study will contribute to the processing and application of laser altimetry data from the GF-7 satellite.
Highlights
Satellite laser altimetry technology has unique advantages in obtaining high-precision surface elevation information [1–3], which can improve the accuracy of the stereo mapping of high-resolution optical remote sensing images, especially elevation accuracy [4–8]
This study constructs a rigorous geometric positioning model for the laser footprint camera (LFC) of the GF-7 satellite and proposes a comprehensive calibration method to eliminate the distortion of the LFC optical system based on the multi-scene images combined with image simulation
The laser altimeter system of the GF-7 satellite has two laser beams, and each beam is equipped with an LFC to record the laser output spots and ground images
Summary
Satellite laser altimetry technology has unique advantages in obtaining high-precision surface elevation information [1–3], which can improve the accuracy of the stereo mapping of high-resolution optical remote sensing images, especially elevation accuracy [4–8]. After on-orbit calibration, the measurement accuracy for the absolute elevation of the GF-7 laser altimeter in a flat area reaches 0.10 m [12], provided that the elevation error caused by horizontal positioning can be ignored in flat terrain. The basis for giving full play to these two functions of the LFC is to realise the high-precision geometric positioning of the laser footprint image. On-orbit calibration must be performed to obtain accurate parameters and improve the geometric positioning accuracy of the laser footprint image. This study constructs a rigorous geometric positioning model for the LFC of the GF-7 satellite and proposes a comprehensive calibration method to eliminate the distortion of the LFC optical system based on the multi-scene images combined with image simulation.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
