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Reject Bragg Peaks Due to Noise/Ionospheric Contamination

Source: R/SeaSondeRCS_FOR.R
seasonder_rejectNoiseIonosphericTest.Rd

This function evaluates Bragg peaks based on the power ratio between the Bragg region and the surrounding non-Bragg region. If the non-Bragg power exceeds the Bragg power by a specified threshold, the peak is rejected.

Usage

seasonder_rejectNoiseIonosphericTest(
  seasonder_cs_object,
  peak,
  range = NA,
  peak_name = ""
)

Arguments

seasonder_cs_object

A SeaSondeRCS object containing spectral data and FOR parameters.

peak

A numeric vector indicating the Doppler bin positions of the peak under evaluation.

range

Optional; A numeric or integer value representing the range cell corresponding to the peak. Defaults to NA.

peak_name

Optional; A character string representing the name or identifier of the peak (e.g., "positive_FOR" or "negative_FOR"). Defaults to an empty string.

Value

A possibly modified version of the peak argument, where a rejected peak is returned as integer(0), indicating that it does not pass the noise/ionospheric test.

Details

Reason for the Test: This test ensures that Bragg peaks are not contaminated by excessive noise or ionospheric interference. Bragg regions with significantly higher non-Bragg power levels are likely to be invalid and are rejected.

Steps:

  1. Threshold Retrieval:

    • Retrieves the reject_noise_ionospheric_threshold parameter, which defines the power difference (in dB) allowed between the Bragg and non-Bragg regions.

  2. Peak Region Determination:

    • Determines whether the peak is in the positive or negative Bragg region based on its location relative to the central Doppler bin.

  3. Non-Bragg Region Extraction:

    • Identifies the non-Bragg region by excluding the bins corresponding to the peak.

  4. Power Calculations:

    • Calculates the total power for the Bragg and non-Bragg regions and converts them to decibels (dB).

  5. Rejection Criterion:

    • If the non-Bragg power exceeds the Bragg power by more than the threshold, the peak is rejected.

    • Logs a message detailing the rejection.

Use Case: This function is particularly useful in environments where noise or ionospheric effects are prevalent, ensuring that only valid first-order Bragg peaks are retained.

See also