Fiber optic gyro digital control with rate extension

In a digitally operated fiber optics gyro system including a light source, a light conducting coil, a splitter to direct the light from the light source to both ends of the coil so that the beams travel in opposite direction through the coil and when subjected to rotation produce a Sagnac phase difference, an optic device to produce a phase change difference in the counter rotating beams, the optic device being driven by a ramp signal which has a periodic 2.pi. reset which produces a 2.pi./SF rate limit, a light sensor for receiving the light from the coil and producing an output indicative of the magnitude of light received which magnitude changes with the rate of rotation, the gyro also including a digital controller for producing a signal indicative of the angle of rotation of the gyro and a signal to produce the ramp input to the optic device, apparatus for eliminating the 2.pi./SF rate limit comprising:

• means supplying the output of the light sensor to the digital controller;
• means for storing the number of 2.pi. resets;
• and
• means combining the light sensor output with the number of 2.pi. resets to produce a signal indicative of the true rate of rotation.