Validation of GaoFen-1 Satellite Geometric Products Based on Reference Data

Abstract

Applications of high-resolution remote sensing satellite data are becoming increasingly extensive. China has launched a series of high-resolution optical satellites: GaoFen-1 (GF-1), GaoFen-2, etc., and published several remote sensing image products. However, validation of the long time series of these satellite geometric products is lacking. Therefore, this study selects 2013–2016 GaoFen-1 satellite geometry products for the Beijing area over four years, obtaining a total of 164 images, and uses ZY-3 satellite products to verify the accuracy of the data set. Moreover, the positioning accuracy of the geometric products of two camera types carried by GF-1 (wide field of view, WFV; panchromatic and multispectral, PMS) is analyzed. The results yield the following conclusions. (1) GF-1 satellite geometric products have obvious systematic errors, and the error value varies significantly with the orbit time. (2) The internal distortion of the GF-1 satellite image is well controlled, and the geometric offset magnitude and direction of ground control points (GCPs) are very similar in the interior of each scene. (3) In a short period of time (20 days), the offset direction of the four WFV cameras is very similar, but there is a small difference in the mean plane offset (RMSE2D). The RMSE2D and offset direction of the two PMS cameras are very similar. (4) In the long term, the relative offset of the WFV and PMS cameras varies with the satellite orbit time. At the first year of the satellite orbit time (in 2014), the relative offsets of four WFV cameras increased to maximum (168.96 m, 171.12 m, 226.65 m, and 207.04 m). From 2015 to 2016, the offsets decreased to a relatively stable state (within 100 m). (5) This validation method based on reference data is shown to be feasible. This study provides an important reference for the application of high-resolution remote sensing satellite products.