A three axis attitude readout system for geosynchronous spacecraft operating at geosynchronous and other orbit altitudes has a two axis sun sensor, a two axis Polaris star tracker, and an infrared single axis earth sensor for use when the sun is behind the earth. The three sensors cooperate with each other such that each sensor has characteristics overcoming inherent weaknesses in the other sensors. The overall system results in a highly accurate three axis readout which could not be achieved by using any of the three sensors alone. The sensor system is designed to be of low weight, low volume and low power consumption.