GEM recently announced the release of its Version 7.0 “Efficiency and GPS” release for its portable magnetometers and gradiometers. This release has been implemented for greater efficiency in handling input and output from GEM’s magnetic instruments as well as for implementation of additional GPS capabilities.
In developing this release, GEM President, Dr. Hrvoic noted that, “A standard issue in geophysical surveys is the expenditure of significant time on non-essential data manipulation tasks. This release streamlines data manipulation in a variety of ways. In addition, it enhances our GPS offering, providing, for example, GPS elevation data which is a key parameter for professionals working with today’s advanced magnetic modeling software.”
Version 7.0 is designed to provide enhancements (through software and accessories — such as Multi-Sensor Boards) that streamline data acquisition and post-processing tasks). Capabilities, benefits and capabilities delivered through the “Efficiency” release, include:
Users of GEM Version 5.0 and 6.0 magnetometers and gradiometers can take advantage of the new features through a migration process. Migrations (i.e. v5.0 to v7.0 and v6.0 to v7.0) are costed to reflect the age of components and associated labor requirements.
As part of the migration, GEM offers a complementary pre-upgrade diagnostic check-up. If any deficiencies in signal quality or components, etc. are noted, we will inform you promptly to determine whether you would like to restore your system to its original working state.
One of the industry standard formats for geophysical data (Encom-, Geosoft-, and Intrepid-compatible) is the line-oriented format. Here, individual lines of data are marked by a simple line number (for example, Line 34) and blocks of data follow until the next line number is encountered, and the process repeats. If line numbers are not provided, the field operator or geophysicist may be required to spend significant time editing the data to input line numbers. GEM has now implemented Standard Line Input Format in its Version 7.0 series instruments to eliminate non-productive data manipulation tasks.
With the increasing availability of proven field-based magnetometer and gradiometer systems equipped with GPS, there is also a key benefit for users – the ability to perform surveys without necessarily laying in a full grid (a time-consuming process that increases survey costs significantly). The key to taking advantage of this benefit is to enable magnetic instrumentation to record data using GPS timing (i.e. automatically).
GEM has implemented this capability; meaning that customers can now perform a) line-oriented surveys without line cutting or b) “random-walk” surveys (i.e. that traverse an irregular pattern or acquire data “around” obstacles).
For line-oriented surveys, the operator or geophysicist first performs the survey. When data are downloaded, the user selects the specified station spacing and the system automatically outputs data with the correct GPS positioning. For irregular surveys, the data is output according to the position recorded at the time that each satellite pulse is received (typically, once a second).
One of the main roles of magnetic surveys is to provide data and positioning information that can be used to return to a specific location for follow-up, such as further surveying using alternate methods or selecting drill targets. GEM now provides a special Picket Marking function that enables the operator to mark a picket position in the field for future reference. This versatile capability also enables the user to mark the location of hazards, cultural objects (such as fences), or rivers, streams, etc.
Lane guidance is a feature that enables users of GPS-configured systems to proceed in a survey with on-screen notification when the operator has exceeded the survey tolerance (i.e. deviation from line). Version 7.0 provides a larger arrow for guidance purposes which enables the operator to more tightly control survey “wander”.
Often an instrument manufacturer’s format is fixed – a scenario that creates difficulties in post-processing data as records may require manipulation to convert them to a format suitable for today’s advanced software packages. In Version 7.0, GEM has implemented Programmable Output to further enhance data efficiency.
Customers have a choice of a default output format or selecting up to 10 data fields. Each field can, in turn, be allocated to a set of 10 pre-defined variables, including X, Y, Elev, Time / GPS Time Total Field1, Corrected Total Field, Grad, SQ (Signal Quality), Number of Satellites, Marker1 and Marker2. More details on the purpose of Marker fields is provided in the Picket Marking summary below.
As technologies advance, many end users of magnetic data are seeking to employ modeling routines for enhanced interpretation, integration of results, and risk reduction. GEM has recognized this need through discussion with key customers and has integrated GPS elevation data as a standard input / output item in Version 7.0. This provides key data required by modeling routines and helps to ensure that magnetic modeling results reflect “true” geology and are not distorted through lack of elevation data.
Today’s personal computers are frequently equipped with Universal Serial Bus ports. USB is a standard port for connecting external devices (such as magnetometers, etc.) to Windows and Macintosh computers. To enable customers to take advantage of the USB ports now provided on many PCs, including laptops, GEM has implemented a standard USB cable for use with its sytems. This cable can be purchased as an accessory for a nominal charge.
GPS-based surveying is only as precise as the resolution to which the system can resolve distances. Previously, GEM’s Universal Transverse Mercator (UTM) precision was 1m; now it has been enhanced to 0.01m. This eliminates a previous scenario in which it was possible to have two or more readings occur at the “same” location. Customers can now resolve positioning data to their full two decimal precision (ex. 1.20 and 1.25). This very high resolution eliminates one source of error (i.e. GPS positioning) and ensures that data locations can be fully resolved for subsequent follow-up (i.e. drilling, excavation, etc.) as required.
GEM has added a software bundle provided through reknowned geophysical software developer, Encom Technology of Australia. This software package is a complement to GEM’s GEMLinkW download software – taking over from GEMLinkW following PC based storage of data.
Users can quickly and easily import data into GEM-VIS and view data in 1D, 2D or 3D as required. Line annotation, posting and other functions are also provided. Valued at US$ 500, this software is provided on a user-support basis (i.e. GEM provides a manual but the software is straight-forward enough that it can be easily learned and then put to good use in the field or office).
A novel feature is that the software can be upgraded in future to Encom’s Profile Analyst and the initial purchase price can be applied to this purchase. Note that GEM also continues to support products from other vendors such as Geosoft (Geophysics Core), Golden Software (Surfer-8) and Pico Envirotech (EMIGMA) so that GEM users have a complete set of software for performing all tasks from data acquisition to interpretation.
GEM is the only major manufacturer to focus on integrating GPS electronics inside its magnetometers and gradiometers – a significant advantage for users in terms of cost, “clean” readings (i.e. minimal noise in contrast to some externally mounted GPS systems), and complexity.
With Version 7.0, GEM now supports an internal board with specifications to <1.5m resolution via WAAS and EGNOS. Customers who are operating outside of these systems can also acquire high resolution GPS using OmniStar or Thales subscription services.
GEM’s Research and Development team is continuously developing new capabilities that will enhance data quality and survey effectiveness. Some of these include:
This capability is based on a) de-spiking (for example, when a user brushes against a tree branch, the magnetometer will automatically handle this type of artificial noise), and on b) optimized measurement period. Here, GEM engineers have extended the measurement period to maximize signal without adding noise.
Both the Overhauser and K-Mag (optically pumped Potassium) series of magnetometers are capable of handling up to four channels of magnetometer readings. This is effective for productivity (i.e. configuration of horizontal sensor installations) as well as for gradient-type readings between sensors arrayed in customer-defined configurations.
This special mode was designed for combined magnetic and electromagnetic readings. In one example, magnetics and VLF sensors were configured in ATV mode and mounted on a fixed platform for towing behind an All Terrain Vehicle.
GEM now offers a non-magnetic towed cart for high productivity or multi-sensor surveys. The cart is made of plastic and facilitates the mounting of sensors and console as required.
For geophysical operators facing the daily challenge of performing high efficiency surveys in sometimes formidable field conditions, it is essential that systems are designed around ergonomic principles. GEM has already incorporated this philosophy in systems such as the industry-leading GSM-19 Overhauser instrument – an extremely light, low-power consuming and robust instrument.
Now, a new ergonomic backpack from a major supplier of outdoor equipment has been added to GEM’s line of accessories. The main benefit is that operators can function more efficiently and acquire more data in a typical day than with heavier alternatives from other suppliers. This capability is especially valuable in extreme temperature conditions; in terrain that is difficult to traverse; or high productivity surveys.
The EUROMAG (GSM-90 and 90F) instrument is specially designed for long-term monitoring in observatory and other stationary type applications. GPS time can now be aquired direct to the magnetometer via an integrated GPS time-only board.
GEM remains a leader in implementation of GPS systems for its high performance line of Overhauser, K-Mag (Potassium) and Proton Precession magnetometers. This position has been enhanced through additional support of more GPS systems from major suppliers. For more information, contact GEM or one of its agents / representatives.
GEM Advanced Magnetometers delivers the only commercially-available magnetometers and gradiometers with embedded GPS for high-sensitivity, accurately-positioned ground surveys. The company’s products include high-sensitivity Overhauser, very-high sensitivity optically pumped Potassium (K-Mag); and latest-technology GSM-19T proton precession instruments. GEM is the global standard in mineral exploration, near surface and observatory systems, and also delivers leading airborne magnetometers. With a 23-year history of innovation in Research and Development (R&D), the company is also known for professional sales and service.
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