We report on the operation of an echelle spectrometer under structured light illumination. Each diffraction order of the spectrometer is encoded with a certain periodic structure allowing for order sorting by numerical analysis after detection. In contrast to cross-dispersed echelle spectrometers, in this approach the orders overlap at the detection plane so that the spectral calibration can be performed easily with a single reference wavelength. This operational simplification makes it possible to measure simultaneously the light source under study and the calibration wavelength giving rise to a self-calibrated echelle spectrometer. In this way the device compensates for the spectral drift due to temporal changes of environmental conditions in real time. Our proposal can be useful in a large number of applications requiring moderate, high or very high resolving power for a wide bandwidth in a non-isolated environment.