An Improved Jitter Detection Method Based on Parallax Observation of Multispectral Sensors for Gaofen-1 02/03/04 Satellites

Ying Zhu,Mi Wang,Lin Xue,Luxiao He,Yufeng Cheng

doi:10.3390/rs11010016

Abstract

Gaofen-1 02/03/04 satellites, the first civilian high resolution optical operational constellation in China, have Earth observation capabilities with panchromatic/multispectral imaging at 2/8 m resolution. Satellite jitter, the fluctuation of satellite points, has a negative influence on the geometric quality of high-resolution optical satellite imagery. This paper presents an improved jitter detection method based on parallax observation of multispectral sensors for Gaofen-1 02/03/04 satellites, which can eliminate the effect of the relative internal error induced by lens distortion, and accurately estimate the parameters of satellite jitter. The relative internal error is estimated by polynomial modelling and removed from the original parallax image generated by pixel-to-pixel image matching between two bands of images. The accurate relative time-varying error and absolute distortion caused by satellite jitter could be estimated by using the sine function. Three datasets of multispectral images captured by Gaofen-1 02/03/04 satellites were used to conduct the experiments. The results show that the relative system errors in both the across- and along-track directions can be modelled with a quadratic polynomial, and satellite jitter with a frequency of 1.1–1.2 Hz in the across-track direction was detected for the first time. The amplitude of the jitter differed in the three datasets. The largest amplitude, from satellite 04, is 1.3 pixels. The smallest amplitude, from satellite 02, is 0.077 pixels. The reliability and accuracy of the detection results were verified by using two groups of band combinations and ortho-images with a 1 m resolution. The comparison results show that the detection accuracy is improved by approximately 30% using the proposed method.

Highlights

Satellite jitter, which is the micro-vibration of satellites, has become one of the most important factors affecting the geometric quality of high-resolution optical satellite imagery [1–4]
The main steps of jitter distortion detection based on ortho-imagery include dense ground control point (GCP) matching, discrepancy calculation based on geometric imaging modelling [32,33], and image distortion fitting by sine function [15]
The discrepancies of the GCPs were calculated with the rational function model (RFM), which was refined by affine modelling to remove the linear system error [35,36]

Summary

Introduction

Satellite jitter, which is the micro-vibration of satellites, has become one of the most important factors affecting the geometric quality of high-resolution optical satellite imagery [1–4]. Satellite jitter has been observed in many high-resolution satellites, including QuickBird, Beijing-1, ALOS, Pleiades, ZiYuan1-02C (ZY1-02C), and ZiYuan-3 (ZY-3) [5–13]. Satellite jitter of 0.6–0.7 Hz was found during the early in-flight data collection of ZiYuan-3, which caused an internal periodic distortion in both the three-line array camera imagery and multispectral camera imagery [13–17]. To remove the negative effect of jitter on the quality of the images and their products, jitter detection is one of most important steps in ground processing systems as it allows distortion caused by satellite jitter to be corrected [4,18]. The published methods of jitter detection can be categorized into two classes.

Results

Discussion

Conclusion