A tutorial on navigation, radar, and identification systems is presented. The topics discussed are the consequences of acceleration sensitivity in crystal oscillators on the Allan variance, including the effects of sinusoidal and random vibration, phase noise and integrated phase jitter; the vector nature of quartz resonator sensitivity; the theoretical description of the cause of the acceleration sensitivity of quartz resonators; techniques for the measurement of acceleration sensitivity; and the effect of frequency multiplication on acceleration effect. Various techniques currently being used or developed for reducing the effective acceleration sensitivity are considered. The techniques fall into three general categories: reduction of the acceleration sensitivity of the resonator; passive techniques that use compensating elements in the oscillator feedback loop, e.g. a second resonator or an acceleration sensitivity capacitor; and active acceleration compensation schemes that sense the acceleration and feedback a compensating signal to a tuning network.