Cotter leads the Quantum Navigation research stream at Imperial's Centre for Cold Matter. He develops compact, fieldable cold-atom inertial sensors for GPS-denied navigation. Milestones: first demonstration of a cold-atom accelerometer on the London Underground (measuring acceleration/vibration in a real transit environment); successful field trials of quantum inertial sensors aboard the Royal Navy research ship XV Patrick Blackett (2023); Arctic field trials with Royal Navy (2025). His sensors use magnetically launched cold-atom Rb clouds and simultaneous multi-axis interferometry. He also contributes to AION-related atom interferometry work and the Quantum Technology Hub in Sensors and Timing. Department of Materials cross-appointment.