vorxmpl.hlp

MATLAB在飞行动力学和控制中应用的工具

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FDC 1.2 - VOR example.
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The subsystem 'VOR example' from the library NAVLIB contains a
demonstration of the practical use of the VOR blocks. First, the
nominal signals are computed in the block VOR (see VOR.HLP).
Then, the steady-state error in the VOR signal is taken into
account (block VORERR, see corresponding help text).

Double-click the subsystem block 'VOR example' to see its inter-
nal structure. Double-click the block VOR and the error block
to specify the parameters for those blocks.

Inputs:
=======
  uvor1 = [xe ye H]'
  uvor2 = psi

where:

  xe : X-coordinate of aircraft in Earth-axes, [m]
  ye : Y-coordinate of aircraft in Earth-axes, [m]
  H  : altitude of aircraft above sea level, [m]
  psi: heading of the aircraft (yaw angle), [rad]

When applied in an autopilot simulation model, these input-
variables usually are OUTPUTS from a NON-LINEAR aircraft model.
The block VOR which computes the nominal values of the VOR sig-
nals does not give correct results if a small-deviations model
is used for the aircraft dynamics! Open the system BEAVER for
an example of such a non-linear aircraft model.

Output:
=======
 yvor  = Gamma_VOR: Angle between chosen VOR-bearing and line
                    from aircraft's c.g. to VOR antenna [rad]

During simulations, the time-trajectories of the VOR signals
and some interim results from the block VOR are sent to the
matrix yvor in the Matlab workspace. Each row from this matrix
corresponds with the vector yvor_workspace at a certain time t,
according to the following definition:

 yvor_workspace = [yvor1; yvor2; yvor3; yvor4]'

 yvor1 = Gamma_VOR
 yvor2 = R_VOR
 yvor3 = [Cone-of-silence-flag, Range-flag]'.
 yvor4 = ToFrom

where:

 Gamma_VOR : Angle between chosen VOR-bearing and line from
             aircraft's c.g. to VOR antenna [rad]
 R_VOR     : 2D-distance from origin of Earth-fixed reference
             frame to VOR (as seen from above) [m]

 The Cone-of-silence-flag is set to 1 if the aircraft enters the
 'cone of silence'. The Range-flag is set to 1 if the aircraft
 flies outside the area where the VOR signals can be received
 with appropriate reliability.

 The variable ToFrom is set to 1 if aircraft is flying towards
 the VOR antenna or 0 if the aircraft flies away from the antenna.

For more info about the definitions of the variables, consult
ref.[1] or the FDC 1.2 user-manual.

References:
===========
[1]. Rauw, M.O. A Simulink environment for Flight Dynamics and
     Control analysis - Application to the DHC-2 'Beaver'
     (2 parts). Graduate's thesis, Delft University of Technology
     (Aerospace Engineering), Delft, September 1993.

More info.
==========
See the helptext VOR.HLP for more info on nominal VOR signals.
See VORERR.HLP for more info on steady-state errors in the VOR
signal.

An example of the practical use of the ILS and VOR blocks can be
found in the 'Beaver' autopilot simulation models APILOT2 and
APILOT3 (in those systems, slightly modified versions of these
models are applied). See also APILOT.HLP.

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The FDC toolbox, Copyright Marc Rauw 1994-1998.