method for estimation of the parameters of the primary particle of an extensive air shower (EAS) by a high-altitude detector complex is described. This method was developed as part of the Pamir-XXI project. The results may be useful for other high-altitude projects and the EAS method in general. The specific configurations of optical detectors for Cherenkov EAS radiation and charged-particle detectors, the methods for data processing, and the attainable accuracy of reconstruction of parameters of primary particles (energy, direction, mass/type) are presented. The results primarily cover optical detectors that are suitable for studying EASs from primary nuclei in the range of energies $E_{0}$ = 100 TeV–100 PeV and showers from primary $\gamma$-quanta with energies of $E_{\gamma}$ ≥ 30 TeV. Grids of charged-particle detectors designed to determine the EAS direction and energy in the $E_{0}$ = 1 PeV–1 EeV range are also considered. The obtained accuracy estimates are the upper limits of the actual experimental accuracies.
96.50.sd Extensive air showers
$^1$Department of General Nuclear Physics, Faculty of physics, Lomonosov Moscow State University, space Research Department.\
$^2$Skobeltsyn Institute of Nuclear Physics, M.V.Lomonosov Moscow State University.\
$^3$Lebedev Physical Institute, Russian Academy of Sciences\
$^4$Umarov Physical-Technical Institute of Academy of Sciences of Tajikistan\
$^5$Tajik National University, Faculty of Physics, Tajikistan