As part of the NAUTILUS research project, the thermal neutron spectrum of the Training Reactor AKR-2 of the Dresden University of Technology is being determined by means of the time-of-flight technique. However, due to the AKR-2 being a zero-power reactor and a facility with low neutron flux, to increase overall counting statistics only a single-disk chopper instead of multiple disk choppers in synchronicity is used in the time-of-flight setup. As no appropriate energy selection is possible with a single-disk chopper, a method was developed for the assessment of real flight times by unfolding measured flight-time data with a flight-time response matrix. This publication presents the current time-of-flight setup at the AKR-2 and the developed deconvolution method. Experimental and simulated flight-time data with the software McStas are shown and compared to theoretical approximations. Results of the deconvolution approach are discussed.