MODELING AND SIMULATION PLAN FOR PRECISION NAVIGATION BASED ON PSEUDOLITES MOUNTED ON AIRSHIPS
burrichandu,
M.Tech,
07,
52 pp.
Department of
Aerospace Engineering
Indian Institute of Technology Bombay,
Powai, Mumbai 400 076.
Supervisor(s):
Rajkumar S.
Pant, Kannan Moudgalya
The three potential risks involved in using GPS based
navigation system for guidance are
integrity risks, availability risks and accuracy risks. The basic
motivation of this study is
to carry out modeling and simulation of a system based on pseudolites
(PLs) mounted on
stratospheric airship platforms (SPFs), to provide precision navigation
to a moving object
within a specific coverage area. The specific aim of the study is to
determine the effect of
movements of the SPFs and the PL monitoring time on the accuracy of
positioning of the
moving object. The proposed pseudolite based simulation model consists
of a few ground
stations as well as pseudolite which are mounted in stratospheric
platforms. The ground
stations are required to continuously monitor the position of the PLs
on the SPFs. By knowing the exact position of the PL antenna, the user
receiver calculates its own position, which is frequently updated to
provide navigation. As the movement of the SPF
increases, the error in the coordinates is high for a given monitoring
time. If we want to
maintain an accuracy of 30m in the user position, the motion of
pseudolite permitted is
0.4m/sec, for a monitoring time of 40ms. If this monitoring time is
reduced to 30ms, then
the permitted motion of the pseudolite is 0.5m/sec. The precision
navigation system has
been modeled in a MATLAB environment.
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