GM(1,1) grey prediction of Lorenz chaotic system

The grey prediction of Lorenz chaotic system will be discussed carefully in this paper. We are mainly using GM(1,1) model to predict data sequences, and the usual prediction precision has exceeded 90%. In the symbolic prediction of Lorenz chaotic dynamical system, the precision of grey prediction certainly will decrease as the length of symbolic sequence is increasing. But in this place we have found a generating rule that may realize chaotic synchronization at least in a short and medium term, and we can analysis and predict in this way.