zero, gaussian processes. The spectral composition of the instrumental noise was determined during ground testing. The SCM sensitivity was characterized at the magnetic test facility in Chambon-la-Forêt. In addition to the internal sensor noise, the DFB analog electronics as well as analog to digital conversion (quantization) of the SCM signal contribute to the end-to-end instrumental noise. The end-to-end noise floor of the MAGs, incorporating quantization and analog electronic noise, were determined in laboratory using measurements taken over several hours inside of a $\mu$-metal container.

The FIELDS SCaM merging procedure is designed to maintain an optimized signal to noise ratio. Each sensor observes the environmental field, which is a coherent signal between two sensors, in superposition with incoherent, zero mean noise.

$$\begin{aligned}
{B_1}=B(t) +n_1(t)\\
{B_2}=B(t) +n_2(t)\end{aligned}$$

The merged signal $B_m$ is given as a linear combination of the individual sensors, weighted by coefficients $\alpha_1$ and $\alpha_2$ which maintain an optimal signal to noise ratio.

As instrumental noise from each sensor has different spectral characteristics, we develop frequency dependent merging coefficients through consideration of the spectral representation of the linear combination of signal and noise terms $$\begin{aligned}
\tilde{B}_m(\omega)=\alpha_1\tilde{B}(\omega) +\alpha_2\tilde{B}(\omega) \\
\tilde{N}_m(\omega)=\sqrt{\alpha_1^2 \tilde{n_1}^2 +\alpha_2^2 \tilde{n_2}^2}\end{aligned}$$

where the merged noise $\tilde{N}_m(\omega)$ corresponds to the 