Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa, 2026. Т. 23. № 3. С. 378-382
Potential accuracy of vertical velocity measurements by the lunar landing module radar
D.B. Balter 1 , A.I. Baskakov 2 , V.V. Egorov 1 , A.A. Komarov 2 , M.V. Stalnaya 1 1 Space Research Institute RAS, Moscow, Russia
2 National Research University "Moscow Power Engineering Institute", Moscow, Russia
Accepted: 27.04.2026
DOI: 10.21046/2070-7401-2026-23-3-378-382
Potential accuracy of vertical velocity V measurements by the onboard radar of the lunar landing module (LM) is calculated. It is noted that the vertical velocity of LM is measured by a Doppler device. The measured vertical velocity values are used in the LM’s closed-loop control. The requirements for the accuracy of vertical velocity measurement are quite stringent: three times its standard deviation must be less than 1% of V, m/s. It is noted that during the final descent, starting from an altitude of 1900 m and below, the error in vertical velocity estimation, when using a smoothing circuit in the meter in the form of an integrator, exceeds the above value. In this regard, it is proposed to use an optimal smoothing circuit in the Doppler vertical velocity meter and to calculate its potential accuracy at one of the stages of the descent.
Keywords: landing module, optimal filter, descent trajectory, Doppler frequency, discriminator, filtering, smoothing circuits, gravitational field, braking, potential accuracy
Full textReferences:
- Bakut P. A., Bol’shakov I. A., Gerasimov B. M., Kuriksha A. A., Repin V. G., Tartakovskii V. G., Shirokov V. V., Voprosy statisticheskoi teorii radiolokatsii (Questions of statistical theory of radar), G. P. Tartakovskii (ed.), V. 2, Moscow: Sovetskoe radio, 1964, 1079 p. (in Russian).
- Balter D. B., Baskakov A. I., Egorov V. V. et al., Principles of construction of the radar station of the lunar landing module and analysis of the accuracy of measuring the altitude and vertical velocity, Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa, 2025, V. 22, No. 4, pp. 375–383 (in Russian), DOI: 10.21046/2070-7401-2025-22-4-375-383.
- Teplyakov I. M., Radiolokatsionnaya stantsiya dlya upravleniya posadkoi kosmicheskogo apparata na poverkhnost’ Luny (Radar station for controlling the landing of a spacecraft on the surface of the Moon), Moscow: IP RadioSoft, 2016, 200 p. (in Russian).