Sensor Function Test

Use the Sensor Function Test option (Geosoft.uxo.gxnet.dll(Geosoft.GX.UXO.UxaSensorTest;Run)*) to ensure the sensor is functioning properly. The test is carried out by comparing a known response of a reference item to a measured (in the field) response. The reference item typically is a medium industry standard object (ISO).

Expand to see the locations (menus) where this option is available.

UX-Analyze extension:

• AGC Dynamic Data > Sensor Tests
• AGC Static Data > Sensor Tests and QC Tools
• AGC Expert User > Dynamic Data Prep and QC
• AGC Expert User > Static Data Prep and QC

Sensor Function Test dialog options

Data with item databases prefix	Select the prefix for the databases containing the field measurement of the reference (ISO) item; refer to Application Notes below for more details. Script Parameter:UXANALYZE.SENSORTEST_DATAPREFIX
Group name	Select the group name. Script Parameter:UXANALYZE.SENSORTEST_ITEMGROUP
Mask channel	Select the mask channel (from the target database) that determines which item is going to be processed. Script Parameter:UXANALYZE.SENSORTEST_TARGETMASK
Gates	Select the low and high time gates from the list. The low and high gates limit the range of data used in the tests. The default values are read from the target database UXA_QCWindowStartTime and UXA_QCWindowEndTime. Script Parameter: UXANALYZE.SENSORTEST_LOGATE UXANALYZE.SENSORTEST_HIGATE
Background databases prefix	Specify the prefix for the background or blank databases (e.g., SBG, SRB). Script Parameter:UXANALYZE.SENSORTEST_BACKGROUNDPREFIX
Group name	Select the group name. Script Parameter:UXANALYZE.SENSORTEST_BACKGROUNDGROUP
Reference item response data	Specify reference item response database. Script Parameter:UXANALYZE.SENSORTEST_REFERENCEGDB
Reference item response data channel	Select the reference data channel. Script Parameter:UXANALYZE.SENSORTEST_REFERENCEDATACHAN
Output Data Range - Single day	When selected, the output plot and CSV file will only show the data associated with the selected day. Script Parameter:UXANALYZE.SENSORTEST_DATERANGE_OPTION
Output Data Range - Date range	When selected, the output plot and CSV file will only show the data associated with the selected date range. Script Parameter:UXANALYZE.SENSORTEST_DATERANGE_OPTION
Output Data Range - All data	When selected, the output plot and CSV file will show all the data. Script Parameter:UXANALYZE.SENSORTEST_DATERANGE_OPTION
Data (x-axis) labels	Select the label for the x-axis of the output plot. Script Parameters:UXANALYZE.SENSORTEST_DATALABEL
Output file name	Specify the output base file name, which is used to generate the output plot and CSV file names. Default name is based on the last date in the database with the reference (ISO) item. The output files will be saved in the .\UXANALYZE_wrk\sensor_plots folder. Script P arameter:UXANALYZE.SENSORTEST_OUTPUTNAME
More
GPS fix quality	Select the GPS fix quality, which can be from 0 to 8. Defa ult value is 4. Script Parameter:UXANALYZE.GPSFIXQ
Test exceptions - No GPS data	When checked, the GPS test will not be applied to the data. Script Parameter:UXANALYZE.SENSORTEST_NOGPS
Test exceptions - No IMU data	When checked, IMU (Inertial Measurement Unit) test will not be applied to the data. Script Parameter:UXANALYZE.SENSORTEST_NOIMU

Application Notes

For the sensor function test, the reference item, a medium industry standard object (ISO), is placed into a cradle on the sensor array, and measurement is taken along a background or blank measurement (i.e. no item). Both the reference item measurement and the background measurement are collected in the exact same location. At least two sensor function tests should be performed each survey day, prior to and after other measurements. Ideally, several sensor function tests would be collected throughout the day, for example, at the same time as the background measurements (i.e., about one per hour for approximately ten measurements per survey day). The measured sensor response for the reference item is compared to the known response for that item. The reference items should be identified with a serial number for tracking purposes.

This test applies for all the advanced EM sensors. The transmitter-receiver combinations and the maximum allowable deviation of the response from the refence item response are defined by the channels 'UXA_QcTransmitterReceiverCombinations' and 'QcReferenceDeviationThreshold' (the HDF v1 schema or newer datasets). For older datasets, the transmitter-receiver combinations depend on the sensor configuration and a maximum deviation threshold of 20%. Depending on the sensor transmitter-receiver configuration, different combinations are examined:

• Systems with a single transmitter coil in a given direction:

• When the transmitter and receiver coils are all orthogonal (i.e. MetalMapper), the sensor function test uses the coaxial terms.

• When the transmitter and receiver coils are not all orthogonal (i.e. MPV), the sensor function test uses the ‘near’ coaxial terms:

• The transmitter with the normal vector (-1,-1,0) is paired with the receivers with a normal vector of (1,1,0).

• The transmitter with the normal vector (1,-1,0) is paired with the receivers with a normal vector of (-1,1,0).

• Systems with an array of multiple transmitter coils in the same direction:

  • Use the coincident terms (i.e., TEM2x2 and MetalMapper2x2).

Processing Steps

The measurements are processed as follows:

1. The measurement with the reference item is checked for quality controlled (Saturated or Flatline response, Current, GPS, and IMU).
2. The background measurement is removed from the measurements with the reference item. The Sensor Function Test automatically determines, based on location and time, which data (blank and item) belong together; they should be at the same location (within 0.1 metre) and at roughly the same time (within five minutes).
3. For a range of sensor data (approximately 0.1 to 0.2 ms), the sensor response data of the background corrected (current normalized) measurement is compared to the sensor response data for the reference item. The default gate ranges are stored in the configuration file. For each of the Tx-Rx combination, the average sensor response over the selected range is calculated. These averages are then compared to the reference signal – if any of them are greater than the maximum allowable deviation from the reference item response.

While not recommended, you can allow certain exceptions to the test (due to a lack of data), for example, no GPS data and/or no IMU data when working with test stand data.

The following metrics are calculated and saved into the sensor function (item) target database:

• Pass/fail mask for the sensor function
• GPS fix quality
• IMU
• Receiver Coil Saturated Signal
• Current of each transmitter; should be greater than the current threshold for the sensor (UXA_TransmitterCurrentThreshold).
  For example: 3.5amps (MPV), 5.0amps (TEM2x2x3), 6.0amps (MetalMapper), and 8.0amps (MetalMapper2x2)
• Location offset between background and sensor function measurements; should be less than 0.05m.
• Time offset between background and sensor function measurements; should be less than 5 minutes.
• Measured response compared to reference, expressed as a percentage difference, should be less than the maximum allowable deviation.

UX-Analyze Configuration File

The boundary limits can be found in "uxa.config", which can be located in the C:\Program Files\Geosoft\Desktop Applications \etc folder: