Daniel Henke

Moving-Target Tracking in Single-Channel Wide-Beam SAR

A novel method for moving-target tracking using single-channel synthetic aperture radar (SAR) with a large antenna beamwidth is introduced and evaluated using a field experiment and real SAR data. The presented approach is based on subaperture SAR processing, image statistics, and multitarget unscented Kalman filtering. The method is capable of robustly detecting and tracking moving objects over time, providing information not only about the existence of moving targets but also about their trajectories in the image space while illuminated by the radar beam. We have successfully applied the method on an experimental data set using miniature SAR to accurately characterize the movement of vehicles on a highway section in the radar image space.

Moving Target Tracking in Single- and Multichannel SAR

Methods for moving target tracking in single- and multichannel synthetic aperture radar (SAR) are presented and evaluated using data from the F-SAR system. An approach based on temporal and spatial overlapping SAR images, image statistics, and multitarget unscented Kalman filtering showed promising results for a single-channel linear SAR experiment. Here, we extend this approach to integrate along-track multichannel data, combine single- and multichannel extraction methods, and verify our results on nonlinear test data on all the different extraction methods. The results are validated and compared with ground-based measurements on a highway section, demonstrating the accuracy of the presented method.

Daily States of the March–April East Pacific ITCZ in Three Decades of High-Resolution Satellite Data

AbstractZonally elongated areas of cloudiness that make up the east Pacific intertropical convergence zone (ITCZ) can take on several configurations in instantaneous observations. A novel statistical model is used to automatically assess the daily state of the east Pacific ITCZ using infrared satellite images from 1980 to 2012. Four ITCZ states are defined based on ITCZ location relative to the equator: north (nITCZ) and south (sITCZ) of the equator, simultaneously north and south of the equator (dITCZ, for double ITCZ), and over the equator (eITCZ). A fifth ITCZ state is used to classify days when no zonally elongated area of cloudiness is present (aITCZ, for absent ITCZ). The ITCZ states can occur throughout the year (except for the eITCZ, which is not present during June–October), with the nITCZ state dominating in terms of frequency of occurrence. Interannual variability of the state distribution is large.The most striking variability in ITCZ states is observed in spring. During March–April, the dITCZ...

Bistatic experiment with the UWB-CARABAS sensor — First results and prospects of future applications

Bistatic SAR experiments are in focus in recent years. We will present first results of an airborne bistatic experiment conducted 2007 in Switzerland with the Swedish ultrawideband sensor CARABAS, operating at 28–73 MHz (UWB). The acquired bistatic data include HH and HV polarization with different bistatic elevation angles, various transmitting flight tracks — including non-linear tracks — and fixed receiving antennas (horizontal and vertical) installed on a mountain top. We will place an emphasis on the processing, improving and evaluating of the data and give an overview of future applications which are made feasible by this bistatic dataset.

A car-borne SAR and InSAR experiment

In this contribution, a car-borne SAR and InSAR experiment is described. The slope of a valley was imaged by means of a single-pass InSAR system mounted on a car driving on roads along the bottom of the valley. The GAMMA portable radar interferometer GPRI-II hardware with a modified antenna configuration was used for data acquisition. The experimental setup (1), SAR imagery focused along a slightly curved sensor trajectory (2), and first interferometric results (3) obtained using this configuration are presented.

Preliminary results of a low-frequency 3D-sar approach for glacier volume mapping

First experimental results with a low-frequency, ultra widebad (UWB) radar for estimating the height of glacier beds are illustrated. We use a 3-dimensional Time-Domain Back-Projection (TDBP) algorithm which incorporates the influence of the refractivity of ice to reconstruct the glacier bed of the Aletsch Glacier in the Swiss Alps using several CARABAS data sets. As the results indicate, the proposed method underlines the ability of low-frequency Synthetic Aperture Radar (SAR) to penetrate into glacier ice and thus, to map glacier volumes on a large scale even with only few, suboptimal data acquisitions.

Tracking and refocussing of moving targets in multichannel SAR data

Moving targets in Synthetic Aperture Radar (SAR) data impose several challenges for SAR processing. In full-aperture SAR images, moving objects appear smeared and/or displaced. In previous studies, we showed that a combination of sub-aperture processing, feature extraction, unscented Kalman filtering and multi-target hypotheses can reliably detect and track moving objects. In this paper, we present some extensions to the tracking algorithm itself, show results on a newly acquired data set and demonstrate how the estimated trajectories of the moving objects can be utilized to refocus the originally smeared objects.

Moving target tracking in single-channel SAR

A method for moving target tracking using single-channel Synthetic Aperture Radar (SAR) is presented. The approach is based on sub-aperture SAR processing, image statistics and multitarget unscented Kalman filtering. It is capable of robustly detecting and tracking moving objects over time, providing information about their trajectories in the image space while illuminated by the radar beam. We have successfully applied the method on experimental data sets using MiSAR and F-SAR to accurately characterize the movement of vehicles on highway sections in the image space.

Moving Target Tracking in SAR Data Using Combined Exo- and Endo-Clutter Processing

Detecting and tracking moving targets in synthetic aperture radar (SAR) data is a challenging task, demanding state-of-the-art processing methods and advanced SAR systems. Current approaches concentrate on the problem of either endo-clutter moving target tracking or exo-clutter moving target tracking, neglecting the advantages of a joint tracking framework. We present an approach relying on a combined exo- and endo-clutter processing scheme using SAR data with a high pulse repetition frequency. The main processing chain is subdivided into four major steps: 1) focusing of temporal and spatial overlapping SAR images; 2) extracting image statistics for each of these subaperture images in the endo- and exo-clutter domains; 3) subsequent tracking of both endo- and exo-clutter observations using multitarget unscented Kalman filtering; and 4) calculating real-world speeds and positions from the SAR image space coordinates using a road network. The results of this approach are validated and compared with ground-based measurements, and it is found that 100% of the vehicles were detected correctly with an accuracy in speed of 0.02 ± 0.31 m/s and an average tracking time of ~28 s.

GMTI in Circular Sar Data Using STAP

This paper presents method and results of a Ground Moving Target Indication (GMTI) experiment using multichannel Synthetic Aperture Radar (M-SAR) data collected by the four channel F-SAR system. The proposed approach is based on sub-aperture processing, Space-Time Adaptive Processing (STAP), constant false alarm rate (CFAR) thresholding and geocoding. The results are validated and compared with results of the same data set from a previous approach based on a combination of single-channel (SC) and Along-Track Interferometry (ATI) detections. It is shown that the STAP-based technique guarantees better performances when detecting moving targets with a small Radar Cross Section (RCS).