The Artemis sensors are set to look for 50/60 Hz or a harmonic from the live power transmission (residual in AC phase imbalance, or from AC-DC conversion).
Unlike alternative technologies on the market, Artemis uses a model-based technique looking at the 3D magnetic field properties to estimate the centre of the target/ magnetic field. This approach handles arbitrary slant angles much better, meaning the performance of the system is maintained even if the ROV moves off the cable.