zero rational function to $\alpha_{MAG}$ for $f>f_0$ with $f_0=2$ Hz. At 2 Hz, $\alpha_{MAG}$ is set to unity, the fit function is constrained to maintain a continuous value and first derivative, such that an extremum is obtained.[]{data-label="merging_fit"}](fig4)

![(a) Analytical approximations of MAG and SCM merging coefficients ($y$-axis shown). (b) Noise floors of MAG (blue) and SCM (red), the coefficient weighted noise floors are shown for MAG (purple) and orange (SCM). The optimal noise floor is plotted in green.[]{data-label="merging_alpha"}](fig5)

Calibration and Merger of In-Flight Survey Data {#sec:inflight}
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![Power spectra densities of observed magnetic field in the spacecraft coordinate $y$ direction from $\approx$ 1 hour interval (2018-11-05/00:00:-01:00) calculated with MAG (blue), SCM (red), and merged SCM and MAG (SCaM, orange), time series. Sensor noise floors are shown for the MAG (teal) and SCM (green).[]{data-label="merging_spect"}](fig6)

![Eight second bandpass filtered waveform near the merging crossover frequency (2-12 Hz) from PSP/FIELDS survey magnetic field data in S/C coordinates. Good phase and gain agreement is observed in between the MAG (blue) SCM (red) and merged SCaM (green) time series.[]{data-label="merging_waves"}](fig7)

During the PSP perihelion encounters, survey mode data are acquired at different cadences, typically varying with solar distance, in order to balance science objectives with telemetry 