Source code for RCAIDE.Library.Mission.Common.Initialize.differentials_altitude
# RCAIDE/Library/Missions/Segments/Common/Update/dimensionless.py
#
#
# Created: Jul 2023, M. Clarke
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# IMPORT
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# package imports
import numpy as np
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# Update Differentials Altitude
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[docs]
def differentials_altitude(segment):
"""
Initializes the differential altitude for mission segment time calculations
Parameters
----------
segment : Segment
The mission segment being analyzed
Notes
-----
This function calculates the time differentials based on altitude changes
in the mission segment. It uses the vertical component of velocity and
position to determine appropriate time steps for integration.
The function performs the following steps:
1. Extracts control points and integration operators
2. Calculates total altitude change
3. Determines time step based on vertical velocity
4. Rescales time operators
5. Updates segment time vector
**Required Segment State Variables**
state.numerics.dimensionless:
- integrate : array
Integration operator matrix
- control_points : array
Normalized time points
state.conditions.frames.inertial:
- position_vector : array
Vehicle position in inertial frame [m]
- velocity_vector : array
Vehicle velocity in inertial frame [m/s]
- time : array
Segment time vector [s]
**Major Assumptions**
* Continuous vertical velocity
* Well-defined altitude change
* No singularities in vertical velocity
Returns
-------
None
Updates segment state directly
See Also
--------
RCAIDE.Framework.Mission.Segments
"""
# unpack
t = segment.state.numerics.dimensionless.control_points
I = segment.state.numerics.dimensionless.integrate
r = segment.state.conditions.frames.inertial.position_vector
v = segment.state.conditions.frames.inertial.velocity_vector
dz = r[-1,2] - r[0,2]
vz = v[:,2,None] # maintain column array
# get overall time step
dt = np.dot( I[-1,:] * dz , 1/ vz[:,0] )
# rescale operators
t = t * dt
# pack
t_initial = segment.state.conditions.frames.inertial.time[0,0]
segment.state.conditions.frames.inertial.time[:,0] = t_initial + t[:,0]
return
