MHO_EstimatePCManual

Purpose

MHO_EstimatePCManual estimates manual phase calibration and delay offset values from post-fringe-fit residuals for stations configured in pc_mode = manual. It computes per-channel phase corrections (pc_phases), per-channel delay offsets (delay_offs), and an overall phase offset (pc_phase_offset) that can be used to refine the control file for a subsequent fringe-fit pass. This is the HOPS4 port of the legacy fearfit manual estimation code.

Control File Trigger

  • Keyword: est_pc_manual (integer parameter, not an operator keyword)

  • Category: manual phase calibration estimation (a descriptive label used only in this document; this operator is not registered under any real pipeline operator_category, see below)

Bitmask modes for est_pc_manual

Bitmask

Hex

Action

Estimate phases

0x001

Per-channel phase correction.

Median channel SBD

0x002

Use median channel single-band delay.

Average channel SBD

0x004

Use average channel single-band delay.

Total SBD

0x008

Use total SBD channel delay.

Measured SBD

0x010

Use original measured SBD values.

Outlier rejection

0x020

Discard SBD outliers using median-based heuristics.

Estimate phase offset

0x040

Estimate overall phase offset.

Phase bias (HOPS_EST_PC_BIAS)

0x080

Apply phase bias from environment variable.

Post-MDLY SBD adjustment

0x100

Adjust SBD after multi-band delay.

Estimate on reference station

sign bit

When set, also estimate on reference station.
There is no dedicated builder for this operator. It is instantiated directly and

driven by the est_pc_manual parameter value.

Input Data

This operator is an inspecting operator on visibility_type. It additionally requires:

  • weight_type for per-channel, per-AP weights.

  • phasor_type containing the fringe-fit residual phasors.

  • MHO_ParameterStore for control-file parameters and fringe-fit results.

  • Plot data (for SBD box values read from /PLOT_INFO).

Algorithm

MHO_EstimatePCManual has a trivial InitializeImpl (always returns true); all work occurs in ExecuteImpl.

Execution (``ExecuteImpl``):

  1. Retrieve the est_pc_manual mode integer from the parameter store and delegate to est_pc_manual(mode).

  2. Mode setup: Retrieve station IDs, polarization products, and per-station pc_mode. The operator only proceeds if both reference and remote stations are in pc_mode = "manual". Decode the mode bitmask to determine which sub-tasks to run: phase estimation (dophs = mode & 0x001), delay estimation (dodly = mode & 0x13e), phase offset (dooff = mode & 0x040), and phase bias (domrp = mode & 0x080). The sign bit determines whether to estimate on the reference station.

Phase Estimation (``est_phases``):

  1. Compute the weighted average phasor per channel: phi_avg = (1 / sum(w)) * sum(w_j * Phi_j), where Phi_j is the phasor for AP j.

  2. Extract the residual phase: theta_resid = arg(phi_avg).

  3. For each channel (sorted by increasing frequency):

    1. Retrieve the net sideband label to determine the sideband multiplier (sbmult = -1 for LSB, +1 for USB).

    2. Retrieve existing manual phase calibrations for both reference and remote stations: est_phase = ref_pc - rem_pc.

    3. Compute the delay correction from fringe residuals: delta_delay = resid_mbd when mbd_anchor = "model"; resid_mbd - resid_sbd when mbd_anchor = "sbd"; 0 otherwise.

    4. Combine: est_phase = est_phase + sbmult * theta_resid * (180/pi) + 360 * delta_delay * (f_chan - f_ref).

    5. Optionally apply phase bias from HOPS_EST_PC_BIAS environment variable.

    6. Canonicalize to principal branch [-180, 180] degrees and adjust relative to the input phase for the target station.

  4. Log the resulting control-file lines with station ID, polarization, channel labels, and estimated phases.

Delay Estimation (``est_delays``):

  1. Read SBD box values from the plot data (/PLOT_INFO/SbdBox).

  2. Convert SBD values from lag units to nanoseconds: sbd[ch] = (sbd[ch] - N_lags - 1) * sbd_sep * 1000.

  3. Negate for the remote station.

  4. Call adj_delays which applies one of five methods based on the how bitmask:

    • 0x02: Use the median channel SBD value.

    • 0x04: Use the average channel SBD value.

    • 0x08: Use the total SBD value.

    • 0x10: Use the measured per-channel SBD values.

    • 0x20: Replace outliers (deviation > 3 sigma from median) with the median before computing the average.

  5. Subtract the delta delay and negate for the remote station. Add the existing manual delay offsets and log the control-file lines.

Phase Offset Estimation (``est_offset``):

  1. Retrieve the fringe-fit residual phase from the parameter store.

  2. Retrieve the existing pcphase_offset for the target station (or use 0 if absent).

  3. Compute the offset: ofs = resphase - pcphase_offset for the reference station, or ofs = -resphase + pcphase_offset for the remote station.

  4. Log the control-file line.

Effect on Data

This operator does not modify the visibility or weight containers. It inspects the phasors, weights, and fringe-fit residuals to compute estimated phase calibration and delay offset values, which are logged as informational control-file lines. The caller can use these values to update the pc_phases, delay_offs, and pc_phase_offset parameters for a subsequent fringe-fit pass.