Filter Powerline Noise

Use the Filter Powerline Noise option (geogxnet.dll(Geosoft.GX.UAVSurvey.FilterPowerlineNoise;Run)*) from the UAV Merge Sorties > Pre-processing menu to remove any powerline interferences from the surveyed data.

Filter Powerline Noise dialog options

Source database	Select the source database from the available list. The field is prepopulated with the active database.
Time channel	Select the time channel. If a "Time" channel is present in the database, it will be automatically selected. The time channel must be continually increasing. Script Parameter: PLAN_UAV_SURVEY.TIME_CHANNEL
Channel to filter	Select the input channel to filter. Script Parameter: PLAN_UAV_SURVEY.CHANNEL_TO_FILTER
Power line frequency	Select the powerline noise to remove. The two frequency options are: 60 Hz (default) and 50 Hz. Script Parameter: PLAN_UAV_SURVEY.DUAL_FREQUENCY_60_50
Output channel	The field defaults to the input channel name appended by _filtered. However, you can change the default before proceeding. Script Parameter: PLAN_UAV_SURVEY.OUTPUT_CHANNEL

Application Notes

When a survey is conducted in the vicinity of AC powerlines, and the data recording sampling rate is higher than the frequency of the AC current, the data will contain systematic noise. The magnitude and interference pattern of this noise depends on the distance from the powerline and the ratio of the sampling rate over the AC frequency. This systematic noise can be removed using a combination of Non-linear and Convolution filters. The 'Filter Powerline Noise' GX applies these filters automatically thus decreasing the overall processing time.