TY - JOUR A1 - Boeniger, Urs A1 - Tronicke, Jens T1 - On the potential of kinematic GPR surveying using a self-tracking total station : evaluating system crosstalk and latency N2 - In this paper, we present an efficient kinematic ground-penetrating radar (GPR) surveying setup using a self- tracking total station (TTS). This setup combines the ability of modern GPR systems to interface with Global Positioning System (GPS) and the capability of the employed TTS system to immediately make the positioning information available in a standardized GPS data format. Wireless communication between the GPR and the TTS system is established by using gain variable radio modems. Such a kinematic surveying setup faces two major potential limitations. First, possible crosstalk effects between the GPR and the positioning system have to be evaluated. Based on multiple walkaway experiments, we show that, for reasonable field setups, instrumental crosstalk has no significant impact on GPR data quality. Second, we investigate systematic latency (i.e., the time delay between the actual position measurement by TTS and its fusion with the GPR data) and its impact on the positional precision of kinematically acquired 2-D and 3-D GPR data. To quantify latency for our kinematic survey setup, we acquired forward-reverse profile pairs across a well-known subsurface target. Comparing the forward and reverse GPR images using three fidelity measures allows determining the optimum latency value and correcting for it. Accounting for both of these potential limitations allows us to kinematically acquire high- quality and high-precision GPR data using off-the-shelf instrumentation without further hardware modifications. Until now, these issues have not been investigated in detail, and thus, we believe that our findings have significant implications also for other geophysical surveying approaches. Y1 - 2010 UR - http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?puNumber=36 U6 - https://doi.org/10.1109/Tgrs.2010.2048332 SN - 0196-2892 ER - TY - JOUR A1 - Boeniger, Urs A1 - Tronicke, Jens A1 - Holliger, Klaus A1 - Becht, Andreas T1 - Multi-offset vertical radar profiling for subsurface reflection imaging JF - Journal of environmental & engineering geophysics : JEEG N2 - The vertical radar profiling (VRP) technique uses surface-to-borehole acquisition geometries comparable to vertical seismic profiling (VSP). Major differences between the two methods do arise due to the fundamentally differing nature of the velocity-depth gradients and transmitter/receiver directivities. Largely for this reason, VRP studies have so far essentially been limited to the reconstruction of velocity-depth profiles by inverting direct arrival times from single-offset VRP surveys. In this study, we investigate the potential to produce high-resolution subsurface reflection images from multi-offset VRP data. Two synthetic data sets are used to evaluate a processing strategy suitably adapted from VSP processing. Despite the fundamental differences between VRP and VSP data, we found that our processing approach is capable of reconstructing subsurface structures of comparable complexity to those routinely imaged by VSP data. Finally, we apply our processing flow to two multi-offset VRP data sets recorded at a well constrained hydrogeophysical test site in SW-Germany. The inferred VRP images are compared with high-quality surface georadar reflection images and lithological logs available at the borehole locations. We find that the VRP images are in good agreement with the surface georadar data and reliably detect the major lithological boundaries. Due to the significantly shorter ray-paths, the depth penetration of the VRP data is, however, considerably higher than that of the surface georadar data. VRP reflection images thus provide an effective means for the depth-calibration and extension of conventional surface georadar data in the vicinity of boreholes. Y1 - 2006 U6 - https://doi.org/10.2113/JEEG11.4.289 SN - 1083-1363 VL - 11 IS - 4 SP - 289 EP - 298 PB - EEGS CY - Denver ER - TY - JOUR A1 - Boeniger, Urs A1 - Tronicke, Jens T1 - Integrated data analysis at an archaeological site : a case study using 3D GPR, magnetic, and high-resolution topographic data N2 - We have collected magnetic, 3D ground-penetrating-radar (GPR), and topographic data at an archaeological site within the Palace Garden of Paretz, Germany. The survey site covers an area of approximately 35 x 40 m across a hill structure (dips of up to 15 degrees) that is partly covered by trees. The primary goal of this study was to detect and locate the remains of ancient architectural elements, which, from historical records, were expected to be buried in the subsurface at this site. To acquire our geophysical data, we used a recently developed surveying approach that combines the magnetic and GPR instrument with a tracking total station (TTS). Besides efficient data acquisition, this approach provides positional information at an accuracy within the centimeter range. At the Paretz field site, this information was critical for processing and analyzing our geophysical data (in particular, GPR data) and enabled us to generate a high-resolution digital terrain model (DTM) of the surveyed area. Integrated analysis and interpretation based on composite images of the magnetic, 3D GPR, and high-resolution DTM data as well as selected attributes derived from these data sets allowed us to outline the remains of an artificial grotto and temple. Our work illustrates the benefit of using multiple surveying technologies, analyzing and interpreting the resulting data in an integrated fashion. It further demonstrates how modern surveying solutions allow for efficient, accurate data acquisition even in difficult terrain. Y1 - 2010 UR - http://geophysics.geoscienceworld.org/ U6 - https://doi.org/10.1190/1.3460432 SN - 0016-8033 ER - TY - JOUR A1 - Boeniger, Urs A1 - Tronicke, Jens T1 - Improving the interpretability of 3D GPR data using target-specific attributes : application to tomb detection (vol 37, pg 360, 2009) N2 - Publisher's not Y1 - 2010 UR - http://www.sciencedirect.com/science/journal/03054403 U6 - https://doi.org/10.1016/S0305-4403(10)00046-4 SN - 0305-4403 ER - TY - JOUR A1 - Boeniger, Urs A1 - Tronicke, Jens T1 - Improving the interpretability of 3D GPR data using target-specific attributes : application to tomb detection N2 - Three-dimensional (3D) ground-penetrating radar (GPR) represents an efficient high-resolution geophysical surveying method allowing to explore archaeological sites in a non-destructive manner. To effectively analyze large 3D GPR data sets, their combination with modern visualization techniques (e.g., 3D isoamplitude displays) has been acknowledged to facilitate interpretation beyond classical time-slice analysis. In this study, we focus on the application of data attributes (namely energy, coherency, and similarity), originally developed for petroleum reservoir related problems addressed by reflection seismology, to emphasize temporal and spatial variations within GPR data cubes. Based on two case studies, we illustrate the potential of such attribute based analyses towards a more comprehensive 3D GPR data interpretation. The main goal of both case studies was to localize and potentially characterize tombs inside medieval chapels situated in the state of Brandenburg, Germany. By comparing the calculated data attributes to the conventionally processed data cubes, we demonstrate the superior interpretability of the coherency and the similarity attribute for target identification and characterization. Y1 - 2010 UR - http://www.sciencedirect.com/science/journal/03054403 U6 - https://doi.org/10.1016/j.jas.2009.09.049 SN - 0305-4403 ER - TY - JOUR A1 - Boeniger, Urs A1 - Tronicke, Jens T1 - High-resolution GPR data analysis using extended tree-based pursuit JF - Journal of applied geophysics N2 - Decomposition of geophysical signals (e.g., seismic and ground-penetrating radar data) into the time-frequency domain can provide valuable information for advanced interpretation (e.g., tuning effects) and processing (e.g., inverse Q-filtering). The quality of these subsequent processing steps is strongly related to the resolution of the selected time-frequency representation (TFR). In this study, we introduce a high-resolution spectral decomposition approach representing an extension of the recently proposed Tree-Based Pursuit (TBP) method. TBP significantly reduces the computational cost compared to the well known Matching Pursuit (MP) technique by introducing a tree structure prior to the actual matching procedure. Following the original implementation of TBP, we additionally incorporate waveforms commonly used in geophysical data processing and present an alternative approach to take phase shifts into account. Application of the proposed method to synthetic data and comparison of the results with other typically used decomposition approaches, illustrate the ability of our approach to provide decomposition results highly localized in both time and frequency. Applying our procedure to field GPR data illustrates its applicability to real data and provides examples for potential applications such as analyzing thin-bed responses and modulating the data frequency content. KW - Ground-penetrating radar KW - Tree-based pursuit KW - Spectral decomposition KW - Signal enhancement Y1 - 2012 U6 - https://doi.org/10.1016/j.jappgeo.2011.04.006 SN - 0926-9851 VL - 78 IS - 5 SP - 44 EP - 51 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Tronicke, Jens A1 - Boeniger, Urs T1 - Denoising magnetic data using steering kernel regression JF - Near surface geophysics N2 - Ground-based magnetic surveying is a common geophysical method to explore near-surface environments in a non-destructive manner. In many typical applications (such as archaeological prospection), the resulting anomaly maps are often characterized by low signal-to-noise ratios and, thus, the suppression of noise is a key step in data processing. Here, we propose the steering kernel regression (SKR) method to denoise magnetic data sets. SKR has been recently developed to suppress random noise in images and video sequences. The core of the method is the steering kernel function which represents a robust estimate of local image structure. Using such a kernel within an iterative regression based denoising framework, helps to minimize image blurring and to preserve the underlying structures such as edges and corners. Because such filter characteristics are desirable for random noise attenuation in potential field data sets, we apply the SKR method for processing high-resolution ground-based magnetic data as they are typically collected in archaeological applications. We test and evaluate the SKR method using synthetic and field data examples and also compare it to more commonly employed denoising strategies relying, for example, on fixed filter masks (e.g., Gaussian filters). Our results show that the SKR method is successful in removing random and acquisition related noise present in our data. Concurrently, it preserves the local image structure including the amplitudes of anomalies. As demonstrated by derivative based transformations, the mentioned filter characteristics significantly impact subsequent processing steps and, therefore, result in an improved analysis and interpretation of magnetic data. Thus, the method can be considered as a promising and novel approach for denoising ground-based magnetic data. Y1 - 2015 U6 - https://doi.org/10.3997/1873-0604.2014038 SN - 1569-4445 SN - 1873-0604 VL - 13 IS - 1 SP - 33 EP - 44 PB - European Association of Geoscientists & Engineers CY - Houten ER - TY - JOUR A1 - Ehlert, C. A1 - Frank, M. A1 - Haley, B. A. A1 - Boeniger, Urs A1 - De Deckker, P. A1 - Gingele, F. X. T1 - Current transport versus continental inputs in the eastern Indian Ocean Radiogenic isotope signatures of clay size sediments JF - Geochemistry, geophysics, geosystems N2 - Analyses of radiogenic neodymium (Nd), strontium (Sr), and lead (Pb) isotope compositions of clay-sized detrital sediments allow detailed tracing of source areas of sediment supply and present and past transport of particles by water masses in the eastern Indian Ocean. Isotope signatures in surface sediments range from -21.5 (epsilon Nd), 0.8299 ((87)Sr/(86S)r), and 19.89 ((206)Pb/(204)Pb) off northwest Australia to + 0.7 (epsilon Nd), 0.7069 ((87)Sr/(86)Sr), and 17.44 ((206)Pb/(204)Pb) southwest of Java. The radiogenic isotope signatures primarily reflect petrographic characteristics of the surrounding continental bedrocks but are also influenced by weathering-induced grain size effects of Pb and Sr isotope systems with superimposed features that are caused by current transport of clay-sized particles, as evidenced off Australia where a peculiar isotopic signature characterizes sediments underlying the southward flowing Leeuwin Current and the northward flowing West Australian Current (WAC). Gravity core FR10/95-GC17 off west Australia recorded a major isotopic change from Last Glacial Maximum values of -10 (epsilon Nd), 0.745 ((87S)r/(86)Sr), and 18.8 ((206)Pb/(204)Pb) to Holocene values of -22 (epsilon Nd), 0.8 ((87)Sr/(86)Sr), and 19.3 ((206)Pb/(204)Pb), which documents major climatically driven changes of the WAC and in local riverine particle supply from Australia during the past 20 kyr. In contrast, gravity core FR10/95-GC5 located below the present-day pathway of the Indonesian throughflow (ITF) shows a much smaller isotopic variability, indicating a relatively stable ITF hydrography over most of the past 92 kyr. Only the surface sediments differ significantly in their isotopic composition, indicating substantial changes in erosional sources attributed to a change of the current regime during the past 5 kyr. KW - Indonesian throughflow KW - Leeuwin Current KW - clay sediments KW - past circulation KW - radiogenic isotopes KW - weathering inputs Y1 - 2011 U6 - https://doi.org/10.1029/2011GC003544 SN - 1525-2027 VL - 12 IS - 12 PB - American Geophysical Union CY - Washington ER -