IFR2
IFR2 combines an IFR1 baseline with time-varying correction for external-field changes during magnetic surveys. Monarch provides SWC-CONUS and SWC-Alaska as regional temporal-correction products, with SWC-Global and local measurement options for other requirements.
Why IFR2
An IFR1 solution provides the static/local magnetic-field baseline used for high-accuracy directional drilling. The external field changes with time as currents in the ionosphere and magnetosphere vary.
IFR2 combines that IFR1 baseline with a time-varying correction so magnetic surveys reflect conditions at the time of operation.
Monarch’s SWC products provide the temporal-correction layer. They can be combined with Monarch IFR1 or with a compatible IFR1 product already in the customer’s workflow.
Regional correction
Space Weather Correction (SWC) uses magnetic observations and spatial modeling to estimate time-varying external-field changes away from observing sites. Combined with a compatible IFR1 baseline, SWC-CONUS or SWC-Alaska provides an IFR2-equivalent regional solution.
SWC-CONUS uses U.S. geomagnetic-observatory data and spatial modeling to estimate external-field variations across the contiguous United States without requiring a local variometer at every drilling location.
SWC-Alaska provides a separate regional correction for Alaska, where higher geomagnetic latitude can produce larger external-field variations and make time-varying correction especially important.
SWC-Global
SWC-Global provides worldwide time-varying magnetic-field correction using approaches suited to different geomagnetic regimes. When combined with IFR1, it provides a global temporal-correction option where regional or local correction is unavailable, although IFR1 + SWC-Global is not classified as IFR2 by ISCWSA. Separately, for legacy HDGM-RT users, HDGM2027 + SWC-Global carries forward HDGM-RT’s global time-varying external-field functionality.
SWC-Global, 12 November 2025. Modeled field-strength disturbance at 08:30 UT, shown for mid- and low latitudes and the northern polar region. Input observations include U.S. Geological Survey (USGS) data and data from broader international geomagnetic providers.
Local correction
Where existing observatory coverage is insufficient, dedicated variometer measurements can provide the temporal-correction layer used with an IFR1 baseline. Depending on the requirement, this could include additional stations that extend regional, SWC-like modeling into new areas or a dedicated near-site deployment following the conventional IFR2 approach. These approaches can be considered where project requirements justify additional local measurements.
Validation & monitoring
SWC products are evaluated against geomagnetic observations to quantify how well the correction reproduces time-varying magnetic-field changes. Monarch monitors SWC product performance in real time and sends alerts when performance is degraded by data gaps or other issues with the underlying observations.
The geomagnetic stack
HDGM provides the global reference field. IFR1 adds local crustal refinement. IFR2 builds on the IFR1 baseline with the time-varying correction needed for conditions at the time of operation.
Time-varying correction
Contact Monarch with the location, operating period, existing IFR1 coverage, and correction requirements. We can determine whether SWC-CONUS, SWC-Alaska, SWC-Global, or a local correction approach is appropriate.
