Open AccessReliability analysis of onboard laser ranging systems for control systems by movement of spacecraft
Author(s) -
Eugeniy Starovoitov
Publication year - 2014
Publication title -
nauka i obrazovanie
Language(s) - English
Resource type - Journals
ISSN - 1994-0408
DOI - 10.7463/0214.0699720
Subject(s) - ranging , spacecraft , laser ranging , reliability (semiconductor) , movement (music) , movement control , computer science , aerospace engineering , satellite laser ranging , control system , remote sensing , environmental science , laser , engineering , geology , physics , telecommunications , optics , acoustics , electrical engineering , physical medicine and rehabilitation , medicine , power (physics) , quantum mechanics
The purpose of this paper is to study and find the ways to improve the reliability of onboard laser ranging system (LRS) used to control the spacecraft rendezvous and descent. The onboard LRS can be implemented with optical-mechanical scanner and without it. The paper analyses the key factors, which influence on the reliability of both LRS. Reliability of LRS is pretty much defined by the reliability of the laser source and its radiation mode. Solid-state diode-pumped lasers are primarily used as a radiation source. The radiation mode, which is defined by requirements for measurement errors of range and speed affect their reliability. The basic assumption is that the resource of solid state lasers is determined by the number pulses of pumping diodes. The paper investigates the influence of radiation mode of solid-state laser on the reliability function when measuring a passive spacecraft rendezvous dosing velocity using a differential method. With the measurement error, respectively, 10 m for range and 0.6 m/s for velocity a reliability function of 0.99 has been achieved. Reducing the measurement error of velocity to 0.5 m/s either results in reduced reliability function <0.99 or it is necessary to reduce the initial error of measurement range up to 3.5...5 m to correspond to the reliability function ≥ 0.995. For the optomechanical scanner-based LRS the maximum pulse repetition frequency versus the range has been obtained. This dependence has been used as a basis to define the reliability function. The paper investigates the influence of moving parts on the reliability of scanning LRS with sealed or unsealed optomechanical unit. As a result, it has been found that the exception of moving parts is justified provided that manufacturing the sealed optomechanical LRS unit is impossible. In this case, the reliability function increases from 0.99 to 0.9999. When sealing the opto-mechanical unit, the same increase in reliability is achieved through duplication of electric motors. Apart from the other publications in the field concerned, this paper discloses the reliability problems of onboard LRS of different types. The results obtained can be used in development of onboard LRS for the long range spacecrafts including those of aimed at missions beyond the Earth orbital operation