GEM – A Long and Storied History

GEM has had a long and storied history – starting as Geophysical Electromagnetic Systems, a consulting partnership. The company incorporated in 1980 as GEM Systems, and is now known in industry as GEM Advanced Magnetometers.


Formed by Drs. Ivan and Jasna Hrvoic, the company continues to be managed by Dr. Hrvoic who contributes many years of experience in geophysical instrumentation and electronic design.


In the late 1960’s and early 1970’s, Dr. Hrvoic worked as Senior Research Engineer with Scintrex Ltd. During this time, initial research was conducted into the feasibility and design of a Continuous Reading High Sensitivity Airborne Overhauser Magnetometer.

This work was completed in 1983 through a research grant and led to the first of an innovative series of magnetometer/gradiometer technologies featuring three main physical principles – Proton quantum magnetometer, Overhauser quantum magnetometer, and the optically pumped Potassium quantum magnetometer.


A History of Innovation

Commercial success of the GSM-8 Proton Precession magnetometer led to early expansion and creation of the GSM-9 Overhauser, the first pulsed Overhauser magnetometer and the GSM-19 Overhauser memory magnetometer – a joint research effort with Lamontagne Geophysics. GSM-10 and 18 magnetometers were also developed and were received well in the resource exploration market.


The company also developed solutions for other fields, such as UXO, volcanology, earthquake prediction, and engineering and environmental disciplines.


Following expansion in 1987, the company launched the GSM-19. This memory magnetometer combines Overhauser technology with proprietary free-radical solutions and firmware that is also able to accept other geophysical methods such as VLF and multiple gradiometer channels. GEM’s team of engineers have now re-packaged the system and enhanced cycle times while establishing industry benchmarks for low weight, low power consumption and high sensitivity.


As the company’s reputation as a proven supplier of instrumentation for total field measurement grew, they branched into other fields, including the observatory field. Today, Overhauser magnetometers have replaced many of the conventional Proton Precession observatory installations around the world.


The Overhauser and Proton magnetometers/gradiometers continued to see success as they moved into later versions, most notably Version 7 which saw many key design and technical enhancements. These magnetometers continue to be developed – even today – justified by their performance and general acceptance in the earth sciences and other subsurface investigations.


In parallel, GEM has initiated a number of research programs designed to provide even more powerful systems for a growing stable of clients around the world. One of these was the implementation of the Potassium magnetometer in conjunction with a Russian research institution.


This magnetometer and its superior sensitivity of 0.3 pT and other features is proving to be one of the most advanced and effective in the world – delivering a new milestone in data quality that surpasses even Overhauser and Proton instruments as well as competing optically pumped cesium magnetometers.


GEM on the Ground

The company has been a leader in providing geophysical instruments for ground surveys based on its Proton, Overhauser, and Potassium sensors and systems. In addition to delivering the highest quality data available from a ground sensor, GEM has also implemented a number of implementations which have affected survey procedures and operations world-wide.


These include the development of the “Walking Mag” – the first magnetometer to provide the operator with the ability to walk continuously while making measurements. This walking mode has increased productivity by 3 to 5 times on the ground since sensor staffs and discrete measurements are no longer required. While this technology has been copied by competitors, GEM remains the originator and developer of the most advanced Walking technologies for magnetometers and gradiometers on the planet today.


Sampling rates delivered by the Overhauser and Potassium systems are suitable for new survey approaches, such as automation. With automation, sensors are mounted on a platform (All-terrain-vehicle, sled, bicycle, or other towed conveyance) and advanced at a rapid rate (5 to 10 km) along the ground surface – resulting in a significant productivity gain for those using one of GEM’s towed carts for instance.


GEM in the Air


GEM’s first airborne project was a vertical helicopter-borne gradiometer created in co-operation with Urtec Instruments and Geotech. It was based on a simple, yet effective self-oscillating Overhauser system. The company also developed the inexpensive GSM-11 airborne magnetometer that contributed to the commercial success of Terraquest Surveys and H. Ferderber Geophysics.


With the development of the Potassium system with its ultra-high sensitivity and fast sampling, GEM advanced even further into the airborne realm. Various flavours of helicopter-borne magnetometers and gradiometers have been developed including a single-sensor magnetometer (GSMP-35A), vertical gradiometer, and the leading three-sensor gradiometer which has been purchased by various organizations around the world.


GEM continues to make advances in the sky, including the recently upgraded airborne VLF system which uses a new tilt sensor to increase the accuracy and time in which measurements can be made.


We also continue to work on fixed wing installations using the GSMP-35A and have a number of these installations up and running now. Expertise includes consulting on sensors and positioning as well as noise sources that must be addressed in order to make accurate measurements from a moving platform.


In our most recent development, we are now building sensors and electronics for Unmanned Airborne Vehicles (UAVs) which are becoming increasingly important in a variety of fields for unmanned airborne surveying.


A Long Term Focus on its Customers

Through its more than three decades of service to the land, airborne and observatory professional community, GEM has continued to seek optimal solutions that will enable its customers to work more cost efficiently and effectively.


In partnership with companies, such as Terraplus Inc., and its network of agents and representatives around the world, GEM thanks its customers and potential customers for their continuing support and input.


Customer input is particularly valued as GEM continues to anticipate strong growth and an ongoing commitment to addressing its customers’ real-world earth science challenges.



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