SOURCEFORGE » RALF » 2015 Simplified communications schemes of Voyager I probe

h1. History and some definitions that you need to know

*History about coding techniques in deep space communications*

Due to the hard conditions in such environment, the development of error-correction codes was essential. Especially, because of the limit power available in space probes and the losses of the signal power across very long distance.

*From 1968*, the first two error-correcting codes were implemented in space missions called *convolutional code* and *Reed-Muller code*. 

*In 1977*, Voyager 1 and voyager 2 were launched into space for a ambitious mission to across the solar system and then the interstellar. These missions were designed to send color image for Jupiter and Saturn. To do this, some improvements were done on the correcting code by concatenating *convolutional codes* with *Golay (24, 12, 8)* for the voyager 1, and *Reed-Solomon code* for voyager 2 which has high error correcting capacity and then able to deliver information about Uranus and Neptune.

*After 1989*, due to ECC system upgrades, both probes used *Reed Solomon Viterbi – Version 2*.

In these days, concatenated codes are less used in space missions and being replaced by more powerful codes such as *Turbo codes* and *LDPC codes*. However, due to different kinds of orbital missions and deep space missions, another problem will be ongoing is about finding “one size fits all” error correction system due to the different amount of noise from earth orbit to deep space.

h3. References

K. Andrews et al., The Development of Turbo and LDPC Codes for Deep-Space Applications, Proceedings of the IEEE, Vol. 95, No. 11, Nov. 2007

Jump up^ Huffman, William Cary; Pless, Vera S. (2003). Fundamentals of Error-Correcting Codes.Cambridge University Press. ISBN 978-0-521-78280-7