Ematrend is an indicator designed by Enrico Malverti that's inspired by the display method of the indicators by Jan Arps and Abraham but with a proprietary formula.
The indicator calculates a level of reverse self-adapting according to the volatility of the financial instrument.

When prices rise above the indicator they generate a signal of strength while when they fall below the indicator they generate a signal of weakness.

The indicator also acts as a dynamic trailing stop level. Ematrend (whose name stands for Enrico Malverti Adaptive Trend) has nothing to do with moving averages and has two parameters:

the first is a multiplier of volatility
the second is the observation period of the indicator.
On time frames lower than the weekly one it is better to progressively extend this parameter in order to make the indicator "smoothed" reducing the false signals.