A Novel Three-Dimensional Block Adjustment Method for Spaceborne InSAR-DEM Based on General Models

Abstract

Digital Elevation Model (DEM) generated by bistatic Synthetic Aperture Radar Interferometry (InSAR) usually has systematic plane and elevation errors. However, the DEM adjustment method based on the function model can only correct systematic elevation error, affecting the plane accuracy of DEM mosaic products. Given this issue, this paper proposes a threedimensional InSAR-DEM block adjustment method based on general models with a separate adjustment strategy, that is, first correct vertical error using the adjustment method based on the function model and then correct horizontal error using the method based on Rational Function Model (RFM) after compensating for elevation errors. In order to extract the Tie Points (TPs) and Ground Control Points (GCPs) used in adjustment, we propose a Normalized Correlation Coefficient matching method based on Complex Slope Maps (NCC-CSM). We conduct experiments using 29 TanDEM-X Co-registered Single look Slant range Complex (CoSSC) data. The accuracies of adjustment results are verified using ICESat-2 ATL08 data and selected GCPs, respectively. The adjustment experiments show that the elevation accuracy of InSAR-DEM is improved from 1.70 m to 1.35 m, the absolute and relative plane accuracies are improved by 5.58 m and 11.53 m, respectively, and the horizontal and vertical geometric discontinuity in the overlapping area disappear. The matching experiments of TPs and GCPs show that the proposed NCC-CSM method is superior to the traditional NCC method based on DEM (NCC-DEM), especially in flat areas.

InSAR-DEM Block Adjustment Model for Upcoming BIOMASS Mission: Considering Atmospheric Effects

“…The National Aeronautics and Space Administration (NASA) has released the fifth version of the land elevation product ATL08 through photon cloud filtering and classification of ICESat-2 ATL03 data [13]. The ATL08 data provide terrain and canopy heights at a 20 m along-track spacing, which has been widely used for DEM systematic error correction or forest height deduction [16,31]. In actual quality assessments, the accuracy of ATL08 terrain elevation can reach 0.73 m [32].…”

“…As the successor to ICESat-1, ICESat-2 offers GCPs with higher spatial resolution and higher repetition rates [13]. Due to the distribution and accuracy of GCPs and ensuring height matching being the keys for systematic error calibration [14,15], researchers began using ICESat-2 as GCPs and considered horizontal errors of DEMs, further improving the block adjustment methods [16,17]. However, the existing block adjustment methods aim to calibrate systematic errors in bistatic mode, whose atmospheric effects can be effectively eliminated through interferometry [18].…”

An On-Site InSAR Terrain Imaging Method with Unmanned Aerial Vehicles

“…InSAR imaging tasks have been operated on spaceborne [28], airborne [29], groundbased [30], and UAV-borne platforms [31]. Spaceborne platforms are typically used to survey wide areas or large-scale phenomena [4], airborne platforms are more flexible in path planning [32], and ground-based platforms are used to monitor local environment [33].…”