摘要 |
A navigation system providing at least (n + 2) transmitters such as artificial satellites of which the positions and velocities are known as a function of time, each of the transmitters emitting at least one known frequency and being positioned so that a receiver can obtain range rate information from (n+2) linearly independent directions and converts said range rate information into knowledge of the position co-ordinates of the receiver in n directions as well as of time and frequency. |