Navigation was based on continuously recording direction and distance through use of a directional gyro and odometer and feeding this data to a computer that would keep track of the overall direction and distance back to the LM . There was also a Sun-shadow device that could give a manual heading based on the direction of the Sun, using the fact that the Sun moved very slowly in the sky.
12.
Avidyne was first to certify big glass for light GA with the launch of Entegra in 2003 in Cirrus aircraft . This is considered a " first generation " big-glass system that integrates the six 3-inch instruments ( 6-pack ) into a more usable package, along with an exceptionally reliable Air Data and Heading Reference System ( ADAHRS ) that replaces the spinning mass attitude and directional gyros.
