A new class of jamming detectors is derived using the hypothesis that jamming causes correlated changes in all the measured Carrier-to-Noise density power ratio (C/No) values. The decision statistics associated to the new detectors have the form of a sum of squared C/No variations and thus, the algorithms developed are named Sum-of-Squares (SoS) detectors. Real-time platforms implementing SoS detection have been developed using a GPS mass-market receiver and an Android device. The tests performed show that jamming detection can be performed using low-cost components and the SoS paradigm.