Quantum sensors have attained unrivaled sensitivities that enable fundamental discoveries and quantum technologies, but they are prone to instability and decoherence via external influences. Exploiting feedback between quantum sensors, the authors present a combinatorial device in which a second quantum system more sensitive to external perturbations is used to stabilize a primary sensor. This approach would use
e.g. both nuclear and electronic spins in diamond to build a stable quantum gyroscope, allowing navigation without GPS. More broadly, this work demonstrates the advantage of colocating a quantum sensor to steady other quantum devices, rather than using bulky classical gear.