The Watson Vertical Reference is a solid state gyro system used to measure angular displacement and rate, especially where dynamic motion may interfere. This is where the effects of lateral acceleration severely limit performance capability of an ordinary device or pendulous device. The Watson vertical reference provides exceptional performance for the price. The Watson Vertical Reference achieves improved performance by integrating a Watson angular rate gyro to get an estimate of attitude and then comparing it with the output from a pendulum to find the error.