Efficient method for spaceborne synthetic aperture radar (SAR) geolocation and application to geometrical SAR image registration

Abstract

An efficient method for spaceborne synthetic aperture radar (SAR) geolocation is devised in this study. In this method, the pixels in the SAR image are divided into two types by a two-dimensional (2D) grid, that is, grid pixels and non-grid pixels. The approach of finding the position of a non-grid pixel is to add the position of the adjacent grid pixel and the position increment between the two pixels together, where the position increment is computed by means of three groups of increment formulae derived according to the principle of first-order Taylor approximation. It is noticed that this method is efficient and helpful in improving the efficiency of the geometrical SAR image registration for avoiding the polynomial fitting and interpolation. In the geometrical registration, the 2D shifts of a non-grid pixel can be expressed as the sum of shifts of the adjacent grid pixel and shift increments between the two pixels. Here the position and 2D shifts of the grid pixel are obtained through the numerical methods for a complete lack of closed-form solutions. Finally, the experiments with TerraSAR-X images are conducted to evaluate the effectiveness of the proposed method.

Data Acquisition of GNSS-Based InSAR: Joint Accuracy-Efficiency Optimization of 3-D Deformation Retrieval

“…The selection of IPs can be based on the coherence between the theoretical resolution cell and the actual resolution cell. For the theoretical resolution cell, the ambiguity function between the target vector Q and its neighboring target vector B can be expressed as (16).…”

“…GNSS-based InSAR has a series of advantages. First, the repeat-pass period is much shorter than that of traditional Low-Earth-Orbit (LEO) SAR [16]- [26]. Considering the Beidou system, which has a Medium Earth Orbit (MEO) satellite and Inclined GeoSynchronous Orbit (IGSO) satellite, as an example, their repeat-pass periods are 7 days and 1 day, respectively.…”

Analysis of X‐band PolInSAR coherence characteristics in forested areas

“…In order to compute the values of and , it is necessary to acquire the position (latitude, longitude and altitude) of every image pixel in advance. The system parameters and shuttle radar topography mission DEM [33] are combined to obtain the pixel position based on the range–Doppler model [34–36]. The obtained pixel altitudes are shown in Fig.…”

Interferometric Phase Error Analysis and Compensation in GNSS-InSAR: A Case Study of Structural Monitoring

“…GNSS-based InSAR has a series of advantages. On the one hand, the repeat-pass period of the proposed system with the Beidou Inclined GeoSynchronous Orbit (IGSO) satellite is 1 day, which is much shorter than that of the traditional InSAR system (for example, the repeat-pass periods of TerraSAR-X, Sentinel-1, COSMO-SkyMed (single satellite) and Radarsat are 11 days, 6 days, 16 days and 24 days, respectively) [7][8][9][10][11]. Thus, the system is better for some rapid deformation scenarios, such as landslides and mining collapses.…”