1. Field of the Invention
The invention generally relates to electronics. In particular, the invention relates to a receiver for a satellite navigation system, such as the NAVSTAR Global Positioning System (GPS).
2. Description of the Related Art
A Global Positioning System (GPS) satellite radiates a spread spectrum, pseudorandom noise (PN) signal indicating the satellite's position and time. A GPS receiver that receives signals from a plurality of satellites can compute the distance to each satellite and then calculate the receiver's spatial position, spatial velocity, and time.
GPS receivers can be used in a broad variety of environments. One application is to provide spatial position and spatial velocity for a projectile, such as an artillery shell. This information can then be used by a guidance system of the projectile to guide the projectile to its intended destination.
Flight corrections can be made by manipulating fins on the projectile. However, the projectile can be configured to spin along an axis in its line of flight to stabilize flight. This spin affects the flight controls for guidance, as the fins will spin with the projectile. In order to make proper flight corrections, the rotational orientation of the projectile should be known.