Optical microbursts (OMBs) of auroral emission were recently detected in the Pulsating Aurora Imaging Photometer System (PAIPS) project. It is the most transient glow in the region of polar auroras discovered to date. PAIPS is a system of two imaging photometers operating on the Kola Peninsula since 2021 aimed to measure a fine spatio-temporal structure of aurora emission. The key question to understand the nature of OMBs is the altitude of the emission which depends on the energy precipitating particles. In this work a spectral method for altitude estimation of auroral emission is developed. A complete simulation of the detector response to the spectrum of molecular nitrogen emission generated during the precipitation of energetic electrons into the atmosphere is carried out. It is shown that the ratio of the signals in two wide wavelength band channels KS11 (600–800 nm) and UFS1 (300–400 nm) depends on the altitude of emission. For the single case with the best meteorological conditions of observation we have estimated the altitude of emission, using our model. It lies in the region of 73–88 km. This altitude corresponds to the precipitating electrons energy 60–200 keV. This measurement is supported by the statistical study of POES charged particles detectors. In most cases, microbursts are measured in the flux tubes of the outer radiation belt with 30–300 keV electrons or at its outer edge. The location in a specific magnetospheric domain and MLT indicate that these OMBs caused by electron precipitation can be a result of wave-particle interaction between magnetospheric waves and electrons.