guidance, flight mechanics and trajectory optimization
guidance, flight mechanics and trajectory optimization
guidance, flight mechanics and trajectory optimization
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
When these expressions are substituted into the,control law, the result may<br />
be interpreted as a sampled data feedback law where the last measurement<br />
occurred at to. Thus,<br />
Another result may be obtained by imagining that the position <strong>and</strong> velocity<br />
are continuously sensed <strong>and</strong> immediately used to correct the thrust. In this<br />
event, a A09 go, <strong>and</strong> to become ,& , g , <strong>and</strong> t <strong>and</strong> a continuous<br />
feedback <strong>guidance</strong> law is obtained, which is<br />
y =-<br />
b u/r<br />
--<br />
(7-tP (7-t)<br />
To express this la-~r in terms of uR (toyCard the target) <strong>and</strong> u1 (normal to the<br />
line of sight), note that 4 = - R&, L/ = -RI, - R E. Next adopting the<br />
notation of expressing a small displacement from the nominal path as a small<br />
angle,<br />
Yields<br />
TARGET f<br />
VEHICI.JZ<br />
Figure 4.5 - Geometry of Rendezvous<br />
73<br />
NOMINAL PATH