metalmapper: a multi-sensor tem and magnetic ......geosoft oasis montaj), and target parameter...

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MetalMapper: A Multi-Sensor TEM and Magnetic Gradiometer System for UXO Detection and Classification ESTCP Project MM-0603 Principal Investigator: Dr. Mark Prouty Geometrics, Inc San Jose, CA [email protected] Objective : The objective of this project is to commercialize advanced tech- nology emerging from recent ESTCP, SERDP, and NAVEODTECHDIV funded EM research. The project draws from the BUD (Berkeley UXO Discriminator) system developed by Lawrence Berkeley Laboratory (ESTCP No. MM-0437), and AOL (Advanced Ordnance Locator) developed by G&G Sciences with fund- ing from NAVEODTECHDIV. We are assembling an advanced electromagnetic induction (EMI) instrument for UXO detection and characterization. The instru- ment will perform substantially better than existing commercially available instru- ments. Technology Description: We are integrating the best parts of the AOL and BUDs. Both systems are time-domain transient (TEM) systems. The AOL system is capable of dual-mode (EMI/Magnetic) acquisition. The 2 nd generation system AOL system is configured with 3 orthogonal transmitter loops, and nine (9) three-axis receiver sensors (27 receiver loops). Recent tests of this system have demonstrated outstanding performance for both high-resolution dynamic mapping of EMI and passive magnetic data as well as for static “Cued-Mode” target characterization. Like the AOL2 system, the BUD system employs a three-loop transmitter, and has a unique receiver geometry consisting of 8 pairs of receiver coils that sense the vertical component of the transient induction field. This system has been demonstrated at YPG and other sites and has demonstrated outstanding performance in both detection and in target parameter recovery. Expected Benefits: The MetalMapper will improve the quality of UXO surveys. The instrument and its software will provide improvements both for de- tection surveys (UXO mapping or raw dig lists) and for characterization surveys (single target classification, false alarm elimination). While operating in its static mode, the MetalMapper will be capable of parameterizing a target with data col- lected at a single field point. This improves results since it eliminates the strict requirements for geolocation (< 1 cm) and for platform attitude measurements that are required when processing data from multiple field points. Expected Results: We will demonstrate a new generation EMI instrument characterized by: Antenna Array – 3-axis transmitter and an array of small triaxial receiv- ers Light-Weight Antenna Platform – A strong, durable, and light-weight antenna platform constructed from surface-reinforced foam components (similar to structural Insulated Panels – SIPs). Man-Portable Data Electronics Package – A portable battery-powered electronics package consisting of a high-speed multi-channel digital data acquisition system, and a digitally controlled bipolar transmitter with multi-loop switching bridges. Integrated Software – Support software that provides near-seamless integration between data acquisition, data display and QC (e.g., Geosoft Oasis montaj), and target parameter extraction. Antenna Array The prototype MetalMapper antenna array consists of 3 transmitter loops and a constellation of 7 tri-axial receiver “cubes” as we illustrate in the nearby Figure. Transmitter Loops The MetalMapper has mutually orthogonal 1m x 1m transmitter loops (X,Y,Z). From a single field point, a target can be illuminated with primary fields in mutually orthogonal directions. Typically, only the Z transmitter loop is energized when surveying in the Dynamic Mode. When surveying in the Static Mode, we time multiplex the transmitter driver between all transmitter loops. Receiver Array The receiver array consists of 7 tri-axial receiver cubes (21 receiver loops). Each loop has nominal dimensions of 10cm x 10cm with an effective area (i.e., turns x area x gain) of 100 m 2 . The receiver cube positions are staggered so that the cube ensemble samples the sec- ondary field at lateral intervals of 13cm. The horizontal components indicate target direction during a dynamic survey. The distribution of cubes within the area outlined by the Z-axis transmitter coil provides near optimal sampling of the secondary transient EM fields for mod- eling static data [1,2]. [1] R. E. Grimm, "Triaxial Modeling and Target Classification of Multichannel, Multi- component EM Data for UXO Discrimination," Jour. Envir. & Eng. Geophys, vol. 8, pp. 239- 250, 2003. [2] J. T. Smith, H. Frank Morrison, and Alex Becker, "Optimizing Receiver Configuration for Resolution of Equivalent Dipole Polarizabilities In Situ," IEEE Trans. on Geosc. & Rem. Sens., vol. 43, pp. 1490-1498, July 2003. Software Support The MetalMapper will be supported with a comprehensive software package providing services for (see Block Diagram—right) Data Acquisition, Physics-based Modeling, and Data Export. Data Acquisition The data acquisition software operates under MS-Windows (XP) and is comprised of two programs. We show a cascaded view of the control screens for TEMAcquire and TEMData in the Figure be- low. The third screen in the cascade is an output from TEMData that provides the instrument operator with a view of a particular data set. The graphical view in this case shows 27 transients for each of 3 transmitter polarizations (Z, Y, and X respectively) for a static data set acquired over target B3 in the Calibration Lanes at Yuma. The target is a 40mm MkII projectile. Physics-based Modeling The MetalMapper (MM) modeling program is a Windows-based program that incorporates a state-of-the-art program developed by Torquil Smith at Lawrence Berkeley Labs. The program, named Rbstmultiprince (RMP) uses a point dipole having an anisotropic polarizability that can vary with time [3]. The Figure below (B) shows the polarizability plots for the target associated with cell B-3 of the Calibration Lanes (YPG) using the transient data (A). [3] J. T. Smith, H. Frank Morrison, "Estimating Equivalent Dipole Polarizabilities for the Inductive Response of Isolated Conductive Bod- ies," IEEE Trans. on Geosc. & Rem. Sens., vol. 42, pp. 1208-1214, 2005. Data Export Raw data from the MetalMapper are most efficiently stored as binary data files in a proprietary format. We can use the program TEMData not only to generate plots of the transients for any particular data point but also to export these data sets into a CSV (Comma Separated Values) text format or into a Geosoft GDB (Geosoft Data- Base). The CSV format is universally accepted by common spreadsheet (e.g.,MS- Excel) and plotting programs (e.g., Surfer). The GDB format is the database struc- ture for Geosoft Oasis montaj™. Post-acquisition QA/QC, map generation, and tar- get picking are provided by Oasis montaj™ together with a few proprietary GX’s (Geosoft eXecutables) developed to handle MM data sets. Demonstraton Schedule Construction of the prototype MetalMapper antenna platform and the associated electronics package is in progress and will be completed by the end of the year. System debugging and local testing will be completed during Q1’08. We anticipate conducting a demonstration at one of the Standardized UXO Technology Demon- stration sites (APG/YPG) during Q2’08. The AOL2 system acquiring dynamic data over NAVEOD’s “Mag Test Site” at Indian Head, MD The BUD system acquiring data at the YPG Standard- ized UXO Technology Demonstration Site in Yuma, Light-Weight Antenna Platform The antenna platform is fabricated using surface-reinforced insulated structural elements. The resulting structure, in this case the antenna plat- form, is very strong and light-weight. Although the assembly of the prototype is not complete yet, we estimate the finished platform will weigh ap- proximately 32 Kg (70 lb). The cart can be quickly and easily disassembled and packed into shipping containers that will be accepted by FedEx or UPS. Electronics Package The electronics package consists of following elements (see block diagram): Transmitter – A digitally controlled transmitter that allows full control over base fre- quency, polarity, duty cycle, and transmitter loop selection. Data Acquisition System – Commercially available data acquisition system contain- ing fully capable PC, 24 channels of high-speed ADC’s, synchronized digital I/O. Control/Display – The system monitor, a Panasonic Toughbook CF-08 Wireless Dis- play provides graphics and touch panel control. Geo-Positioning/Attitude System – Geo-positioning is provided by an RTK GPS sys- tem. Platform attitude is measured by a 2-axis inclinometer with a geomagnetic refer- ence. Mag Gradiometer Subsystem – The MetalMapper can operate in a dual acquisition mode, acquiring both transient EM data and total field magnetic readings. The system includes 2 Cs magnetometers (Geometrics Model G-822A/823A) so that it can operate as a finite total field gradiometer. MetalMapper: 7-Cube receiver array Diagram showing the position of the 7 re- ceiver cubes. All receivers are in the plane of the Z transmitter loop. Functional block diagram of the MetalMapper system. Block diagram showing the key elements of the integrated software system supporting data acquisition, physics-based modeling, and post-acquisition QA/QC and data processing. EM Detection map generated from AOL2 ex- ported and processed with Oasis montaj. Light-weight construction (~75lbs) Multi-axis transmitter loops (3) 7 tri-axial receiver cubes Skid or wheel deployment Man-Portable or Vehicular-towed 3-D rendering of the assembled MetalMapper an- tenna platform Unassembled antenna and cart parts Weight: 39 lbs * Dimensions: 8.5 x 9.75 x 14.5 in Battery Life (Li-Ion ): 4-6 hr Battery Pack Case Internal View Front Panel Touch Screen Display

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Page 1: MetalMapper: A Multi-Sensor TEM and Magnetic ......Geosoft Oasis montaj), and target parameter extraction. Antenna Array The prototype MetalMapper antenna array consists of 3 transmitter

MetalMapper: A Multi-Sensor TEM and Magnetic Gradiometer System for UXO Detection and Classification ESTCP Project MM-0603

Principal Investigator: Dr. Mark Prouty Geometrics, Inc

San Jose, CA [email protected]

Objective: The objective of this project is to commercialize advanced tech-nology emerging from recent ESTCP, SERDP, and NAVEODTECHDIV funded EM research. The project draws from the BUD (Berkeley UXO Discriminator) system developed by Lawrence Berkeley Laboratory (ESTCP No. MM-0437), and AOL (Advanced Ordnance Locator) developed by G&G Sciences with fund-ing from NAVEODTECHDIV. We are assembling an advanced electromagnetic induction (EMI) instrument for UXO detection and characterization. The instru-ment will perform substantially better than existing commercially available instru-ments. Technology Description: We are integrating the best parts of the AOL and BUDs. Both systems are time-domain transient (TEM) systems. The AOL system is capable of dual-mode (EMI/Magnetic) acquisition.

The 2nd generation system AOL system is configured with 3 orthogonal transmitter loops, and nine (9) three-axis receiver sensors (27 receiver loops). Recent tests of this system have demonstrated outstanding performance for both high-resolution dynamic mapping of EMI and passive magnetic data as well as for static “Cued-Mode” target characterization.

Like the AOL2 system, the BUD system employs a three-loop transmitter, and has a unique receiver geometry consisting of 8 pairs of receiver coils that sense the vertical component of the transient induction field. This system has been demonstrated at YPG and other sites and has demonstrated outstanding performance in both detection and in target parameter recovery.

Expected Benefits: The MetalMapper will improve the quality of UXO surveys. The instrument and its software will provide improvements both for de-tection surveys (UXO mapping or raw dig lists) and for characterization surveys (single target classification, false alarm elimination). While operating in its static mode, the MetalMapper will be capable of parameterizing a target with data col-lected at a single field point. This improves results since it eliminates the strict requirements for geolocation (< 1 cm) and for platform attitude measurements that are required when processing data from multiple field points.

Expected Results: We will demonstrate a new generation EMI instrument characterized by:

• Antenna Array – 3-axis transmitter and an array of small triaxial receiv-ers

• Light-Weight Antenna Platform – A strong, durable, and light-weight antenna platform constructed from surface-reinforced foam components (similar to structural Insulated Panels – SIPs).

• Man-Portable Data Electronics Package – A portable battery-powered electronics package consisting of a high-speed multi-channel digital data acquisition system, and a digitally controlled bipolar transmitter with multi-loop switching bridges.

• Integrated Software – Support software that provides near-seamless integration between data acquisition, data display and QC (e.g., Geosoft Oasis montaj), and target parameter extraction.

Antenna Array

The prototype MetalMapper antenna array consists of 3 transmitter loops and a constellation of 7 tri-axial receiver “cubes” as we illustrate in the nearby Figure. Transmitter Loops The MetalMapper has mutually orthogonal 1m x 1m transmitter loops (X,Y,Z). From a single field point, a target can be illuminated with primary fields in mutually orthogonal directions. Typically, only the Z transmitter loop is energized when surveying in the Dynamic Mode. When surveying in the Static Mode, we time multiplex the transmitter driver between all transmitter loops. Receiver Array The receiver array consists of 7 tri-axial receiver cubes (21 receiver loops). Each loop has nominal dimensions of 10cm x 10cm with an effective area (i.e., turns x area x gain) of 100 m2. The receiver cube positions are staggered so that the cube ensemble samples the sec-ondary field at lateral intervals of 13cm. The horizontal components indicate target direction during a dynamic survey. The distribution of cubes within the area outlined by the Z-axis transmitter coil provides near optimal sampling of the secondary transient EM fields for mod-eling static data [1,2]. [1] R. E. Grimm, "Triaxial Modeling and Target Classification of Multichannel, Multi-component EM Data for UXO Discrimination," Jour. Envir. & Eng. Geophys, vol. 8, pp. 239-250, 2003. [2] J. T. Smith, H. Frank Morrison, and Alex Becker, "Optimizing Receiver Configuration for Resolution of Equivalent Dipole Polarizabilities In Situ," IEEE Trans. on Geosc. & Rem. Sens., vol. 43, pp. 1490-1498, July 2003.

Software Support The MetalMapper will be supported with a comprehensive software package providing services for (see Block Diagram—right) Data Acquisition, Physics-based Modeling, and Data Export. Data Acquisition The data acquisition software operates under MS-Windows (XP) and is comprised of two programs. We show a cascaded view of the control screens for TEMAcquire and TEMData in the Figure be-low. The third screen in the cascade is an output from TEMData that provides the instrument operator with a view of a particular data set. The graphical view in this case shows 27 transients for each of 3 transmitter polarizations (Z, Y, and X respectively) for a static data set acquired over target B3 in the Calibration Lanes at Yuma. The target is a 40mm MkII projectile. Physics-based Modeling The MetalMapper (MM) modeling program is a Windows-based program that incorporates a state-of-the-art program developed by Torquil Smith at Lawrence Berkeley Labs. The program, named Rbstmultiprince (RMP) uses a point dipole having an anisotropic polarizability that can vary with time [3]. The Figure below (B) shows the polarizability plots for the target associated with cell B-3 of the Calibration Lanes (YPG) using the transient data (A). [3] J. T. Smith, H. Frank Morrison, "Estimating Equivalent Dipole Polarizabilities for the Inductive Response of Isolated Conductive Bod-

ies," IEEE Trans. on Geosc. & Rem. Sens., vol. 42, pp. 1208-1214, 2005.

Data Export Raw data from the MetalMapper are most efficiently stored as binary data files in a proprietary format. We can use the program TEMData not only to generate plots of the transients for any particular data point but also to export these data sets into a CSV (Comma Separated Values) text format or into a Geosoft GDB (Geosoft Data-Base). The CSV format is universally accepted by common spreadsheet (e.g.,MS-Excel) and plotting programs (e.g., Surfer). The GDB format is the database struc-ture for Geosoft Oasis montaj™. Post-acquisition QA/QC, map generation, and tar-get picking are provided by Oasis montaj™ together with a few proprietary GX’s (Geosoft eXecutables) developed to handle MM data sets.

Demonstraton Schedule Construction of the prototype MetalMapper antenna platform and the associated electronics package is in progress and will be completed by the end of the year. System debugging and local testing will be completed during Q1’08. We anticipate conducting a demonstration at one of the Standardized UXO Technology Demon-stration sites (APG/YPG) during Q2’08.

The AOL2 system acquiring dynamic data over NAVEOD’s “Mag Test Site” at Indian Head, MD

The BUD system acquiring data at the YPG Standard-ized UXO Technology Demonstration Site in Yuma,

Light-Weight Antenna Platform

The antenna platform is fabricated using surface-reinforced insulated structural elements. The resulting structure, in this case the antenna plat-form, is very strong and light-weight. Although the assembly of the prototype is not complete yet, we estimate the finished platform will weigh ap-proximately 32 Kg (70 lb). The cart can be quickly and easily disassembled and packed into shipping containers that will be accepted by FedEx or UPS.

Electronics Package The electronics package consists of following elements (see block diagram):

• Transmitter – A digitally controlled transmitter that allows full control over base fre-quency, polarity, duty cycle, and transmitter loop selection.

• Data Acquisition System – Commercially available data acquisition system contain-ing fully capable PC, 24 channels of high-speed ADC’s, synchronized digital I/O.

• Control/Display – The system monitor, a Panasonic Toughbook CF-08 Wireless Dis-play provides graphics and touch panel control.

• Geo-Positioning/Attitude System – Geo-positioning is provided by an RTK GPS sys-tem. Platform attitude is measured by a 2-axis inclinometer with a geomagnetic refer-ence.

• Mag Gradiometer Subsystem – The MetalMapper can operate in a dual acquisition mode, acquiring both transient EM data and total field magnetic readings. The system includes 2 Cs magnetometers (Geometrics Model G-822A/823A) so that it can operate as a finite total field gradiometer.

MetalMapper: 7-Cube receiver array

Diagram showing the position of the 7 re-ceiver cubes. All receivers are in the plane of the Z transmitter loop.

Functional block diagram of the MetalMapper system.

Block diagram showing the key elements of the integrated software system supporting data acquisition, physics-based modeling, and post-acquisition QA/QC and data processing.

EM Detection map generated from AOL2 ex-ported and processed with Oasis montaj.

• Light-weight construction (~75lbs) • Multi-axis transmitter loops (3) • 7 tri-axial receiver cubes • Skid or wheel deployment

• Man-Portable or • Vehicular-towed

3-D rendering of the assembled MetalMapper an-tenna platform

Unassembled antenna and cart parts

Weight: 39 lbs * Dimensions: 8.5 x 9.75 x 14.5 in Battery Life (Li-Ion ): 4-6 hr

Battery Pack Case

Internal View Front Panel

Touch Screen Display