GEOPY-3045: Missing unit conversion for Frequency systems

[domfournier]

GEOPY-3045 - Missing unit conversion for Frequency systems

[Copilot]

Pull request overview

This PR addresses GEOPY-3045 by ensuring Frequency-Domain EM (FEM/FDEM) frequencies are correctly interpreted when the dataset’s frequency unit is not plain Hertz, by introducing unit-aware conversion in survey construction and updating the synthetic FDEM survey metadata/test expectations.

Changes:

• Store synthetic FDEM frequencies in kHz (instead of Hz) and record the intended frequency unit on the survey.
• Apply unit_conversion when building FDEM survey frequency arguments and when populating SimPEG survey _frequencies.
• Update the FEM driver test uncertainty scaling to reflect the new frequency unit convention.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
tests/run_tests/driver_airborne_fem_test.py	Adjusts uncertainty scaling to account for frequency unit changes in synthetic FDEM surveys.
simpeg_drivers/utils/synthetics/surveys/frequency_domain/fdem.py	Updates synthetic FDEM frequency configuration to kHz and attempts to set the survey’s frequency unit.
simpeg_drivers/components/factories/survey_factory.py	Converts FEM channel frequencies using unit_conversion before constructing SimPEG sources.
simpeg_drivers/components/data.py	Ensures SimPEG survey _frequencies reflect unit-converted channel values.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.27%. Comparing base (8d7c87e) to head (81f68a0).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #464      +/-   ##
===========================================
+ Coverage    90.25%   90.27%   +0.01%     
===========================================
  Files          113      113              
  Lines         7022     7021       -1     
  Branches       867      867              
===========================================
  Hits          6338     6338              
+ Misses         467      466       -1     
  Partials       217      217              

Files with missing lines	Coverage Δ
simpeg_drivers/components/data.py	95.60% <100.00%> (ø)
...peg_drivers/components/factories/survey_factory.py	94.92% <100.00%> (ø)
...ivers/electromagnetics/frequency_domain/options.py	91.54% <100.00%> (+1.40%)	⬆️
...eg_drivers/electromagnetics/time_domain/options.py	100.00% <100.00%> (ø)
...s/natural_sources/apparent_conductivity/options.py	100.00% <100.00%> (ø)
...rivers/natural_sources/magnetotellurics/options.py	98.21% <100.00%> (-0.04%)	⬇️
simpeg_drivers/natural_sources/tipper/options.py	100.00% <100.00%> (ø)
.../utils/synthetics/surveys/frequency_domain/fdem.py	88.88% <100.00%> (+0.31%)	⬆️

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[gmcga]

_frequencies is converted to Hz here, but it looks like _naturalsource_arguments still passes the raw data.entity.channels values to SourcesFactory. For units other than Hz does this mean the survey and its sources would end up using different values for frequencies in different places, e.g. for 0.9 kHz, source.frequency and survey._frequency_dict would be left as 0.9 while survey._frequencies would be 900.0?

[gmcga]

(I'm not 100% sure this is how everything will work but I thought I should bring it up just in case)