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ISCE_INSAR/components/isceobj/Orbit/Orbit.py

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2019-01-16 19:40:08 +00:00
#
# Author: Walter Szeliga
# Copyright 2010, by the California Institute of Technology. ALL RIGHTS
# RESERVED. United States Government Sponsorship acknowledged. Any commercial
# use must be negotiated with the Office of Technology Transfer at the
# California Institute of Technology.
#
# This software may be subject to U.S. export control laws. By accepting this
# software, the user agrees to comply with all applicable U.S. export laws and
# regulations. User has the responsibility to obtain export licenses, or other
# export authority as may be required before exporting such information to
# foreign countries or providing access to foreign persons.
#
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
import datetime
import numpy as np
import logging
import operator
from functools import reduce
#from iscesys.DateTimeUtil.DateTimeUtil import DateTimeUtil as DTU
from iscesys import DateTimeUtil as DTU
from iscesys.Traits.Datetime import datetimeType
from iscesys.Component.Component import Component
from isceobj.Util.decorators import type_check, pickled, logged
# This class stores platform position and velocity information.
POSITION = Component.Parameter(
'_position',
public_name='POSITION',
default=[],
container=list,
type=float,
mandatory=True,
doc=''
)
TIME = Component.Parameter(
'_time',
public_name='TIME',
default=[],
type=datetimeType,
mandatory=True,
doc=''
)
VELOCITY = Component.Parameter(
'_velocity',
public_name='VELOCITY',
default=[],
container=list,
type=float,
mandatory=True,
doc=''
)
class StateVector(Component):
parameter_list = (POSITION,
TIME,
VELOCITY
)
family = 'statevector'
def __init__(self,family = None, name = None, time=None, position=None, velocity=None):
super().__init__(
family=family if family else self.__class__.family, name=name)
super(StateVector, self).__init__()
self._time = time
self._position = position or []
self._velocity = velocity or []
return None
def __iter__(self):
return self
@type_check(datetime.datetime)
def setTime(self, time):
self._time = time
pass
def getTime(self):
return self._time
def setPosition(self, position):
self._position = position
def getPosition(self):
return self._position
def setVelocity(self, velocity):
self._velocity = velocity
def getVelocity(self):
return self._velocity
def getScalarVelocity(self):
"""Calculate the scalar velocity M{sqrt(vx^2 + vy^2 + vz^2)}.
@rtype: float
@return: the scalar velocity
"""
return reduce(operator.add, [item**2 for item in self.velocity])**0.5
def calculateHeight(self, ellipsoid):
"""Calculate the height above the provided ellipsoid.
@type ellipsoid: Ellipsoid
@param ellipsoid: an ellipsoid
@rtype: float
@return: the height above the ellipsoid
"""
print("Orbit.calculateHeight: self.position = ", self.position)
print("Orbit.calculateHeight: ellipsoid.a, ellipsoid.e2 = ",
ellipsoid.a, ellipsoid.e2)
lat, lon, height = ellipsoid.xyz_to_llh(self.position)
return height
def __lt__(self, other):
return self.time < other.time
def __gt__(self, other):
return self.time > other.time
def __cmp__(self, other):
return (self.time>other.time) - (self.time<other.time)
# def __eq__(self, other):
# return self._time == other._time
def __eq__(self, other):
return ((self._time == other._time) and
(self._position == other._position) and
(self._velocity == other._velocity))
def __str__(self):
retstr = "Time: %s\n"
retlst = (self._time,)
retstr += "Position: %s\n"
retlst += (self._position,)
retstr += "Velocity: %s\n"
retlst += (self._velocity,)
return retstr % retlst
time = property(getTime,setTime)
position = property(getPosition,setPosition)
velocity = property(getVelocity,setVelocity)
pass
STATE_VECTOR = Component.Facility('stateVector',
public_name='STATE_VECTOR',
module='isceobj.Orbit.Orbit',
factory='StateVector',
doc='State Vector properties used by STATE_VECTORS'
)
STATE_VECTORS = Component.Facility('_stateVectors',
public_name='STATE_VECTORS',
module='iscesys.Component',
factory='createTraitSeq',
args=('statevector',),
mandatory=False,
doc='Testing Trait Sequence'
)
ORBIT_QUALITY = Component.Parameter('_orbitQuality',
public_name='ORBIT_QUALITY',
default = '',
type=str,
mandatory=False,
doc="Orbit quality"
)
ORBIT_SOURCE = Component.Parameter('_orbitSource',
public_name='ORBIT_SOURCE',
default = '',
type=str,
mandatory=False,
doc="Orbit source"
)
ORBIT_REFERENCE_FRAME = Component.Parameter('_referenceFrame',
public_name='ORBIT_REFERENCE_FRAME',
default = '',
type=str,
mandatory=False,
doc="Orbit reference frame"
)
MIN_TIME = Component.Parameter('_minTime',
public_name = 'MIN_TIME',
default=datetime.datetime(year=datetime.MAXYEAR,month=12,day=31),
type=datetimeType,
mandatory=True,
doc=''
)
MAX_TIME = Component.Parameter('_maxTime',
public_name = 'MAX_TIME',
default=datetime.datetime(year=datetime.MINYEAR,month=1,day=1),
type=datetimeType,
mandatory=True,
doc=''
)
##
# This class encapsulates orbital information\n
# The Orbit class consists of a list of \c StateVector objects
# and provides an iterator over this list.
@pickled
class Orbit(Component):
'''
REMOVE completely once conversion to Configurable is done
dictionaryOfVariables = {'STATE_VECTORS':
['_stateVectors',float, 'mandatory'],
'ORBIT_QUALITY': ['_orbitQuality',str,'optional'],
'ORBIT_SOURCE': ['_orbitSource',str, 'optional'],
'ORBIT_REFERENCE_FRAME':
['_referenceFrame',str,'optional']
}
'''
logging_name = "isce.Orbit"
# _minTime = datetime.datetime(year=datetime.MAXYEAR,month=12,day=31)
# _maxTime = datetime.datetime(year=datetime.MINYEAR,month=1,day=1)
family = "orbit"
parameter_list = (
ORBIT_QUALITY,
ORBIT_SOURCE,
ORBIT_REFERENCE_FRAME,
MIN_TIME,
MAX_TIME,
)
facility_list = (STATE_VECTORS,)
@logged
def __init__(self,family = None, name = None, source=None, quality=None, stateVectors=None):
super().__init__(family=family if family else self.__class__.family,
name=name)
self.configure()
self._last = 0
self._orbitQuality = quality or None
self._orbitSource = source or None
self._referenceFrame = None
self._stateVectors.configure()
#self._stateVectors = stateVectors or []
self._cpStateVectors = []
type(self._stateVectors)
return None
#since the dump works only with primitives, convert the self._stateVectors to a list of lists
#instead of a list of state vectors
#def dump(self,filename):
# self.adaptToRender()
# super(Orbit,self).dump(filename)
# #restore in original format
# self.restoreAfterRendering()
#def load(self,filename):
# import copy
# import datetime
# # when loaded up the stateVectors are just list of lists and the starting time is
# # ins str format
# super(Orbit,self).load(filename)
# #make a copy
# cpStateVectors = copy.deepcopy(self._stateVectors)
# #convert the str into datetime
# cpStateVectors[3] = datetime.datetime.strptime(cpStateVectors[3],'%Y-%m-%dT%H:%M:%S.%f')
# #pack the orbit into stateVectors
# self._packOrbit(cpStateVectors[0], cpStateVectors[1], cpStateVectors[2], cpStateVectors[3])
def adaptToRender(self):
import copy
# make a copy of the stateVectors to restore it after dumping
self._cpStateVectors = copy.deepcopy(self._stateVectors)
#self._stateVectors = list(self._unpackOrbit())
#self._stateVectors[3] = self._stateVectors[3].strftime('%Y-%m-%dT%H:%M:%S.%f')
def restoreAfterRendering(self):
self._stateVectors = self._cpStateVectors
def __iter__(self):
return self
def __len__(self):
return len(self.stateVectors)
def __getitem__(self, index):
return self.stateVectors[index]
def __contains__(self, time):
return self._inRange(time)
@property
def stateVectors(self):
return self._stateVectors
@property
def maxTime(self):
return self._maxTime
@maxTime.setter
def maxTime(self, time):
self._maxTime = time
@property
def minTime(self):
return self._minTime
@minTime.setter
def minTime(self, time):
self._minTime = time
def setOrbitQuality(self,qual):
self._orbitQuality = qual
def getOrbitQuality(self):
return self._orbitQuality
def setOrbitSource(self,source):
self._orbitSource = source
def getOrbitSource(self):
return self._orbitSource
def setReferenceFrame(self,ref):
self._referenceFrame = ref
def getReferenceFrame(self):
return self._referenceFrame
@type_check(StateVector)
def addStateVector(self, vec):
"""
Add a state vector to the orbit.
@type vec: Orbit.StateVector
@param vec: a state vector
@raise TypeError: if vec is not of type StateVector
"""
pos = vec.getPosition()
import math
posmag = math.sqrt(sum([x*x for x in pos]))
if posmag > 1.e10:
print("Orbit.addStateVector: vec = ", vec)
import sys
sys.exit(0)
vtime = vec.getTime()
if vtime > self.maxTime:
self._stateVectors.append(vec)
else:
for ind, sv in enumerate(self._stateVectors):
if sv.time > vtime:
break
self._stateVectors.insert(ind, vec)
# Reset the minimum and maximum time bounds if necessary
if vec.time < self.minTime: self.minTime = vec._time
if vec.time > self.maxTime: self.maxTime = vec._time
def __next__(self):
if self._last < len(self):
next = self._stateVectors[self._last]
self._last += 1
return next
else:
self._last = 0 # This is so that we can restart iteration
raise StopIteration()
def interpolateOrbit(self, time, method='linear'):
"""Interpolate the state vector of the orbit at a given time.
@type time: datetime.datetime
@param time: the time at which interpolation is desired
@type method: string
@param method: the interpolation method, valid values are 'linear',
'legendre' and 'hermite'
@rtype: Orbit.StateVector
@return: a state vector at the desired time otherwise None
@raises ValueError: if the time lies outside of the time spanned by
the orbit
@raises NotImplementedError: if the desired interpolation method
cannot be decoded
"""
if time not in self:
raise ValueError(
"Time stamp (%s) falls outside of the interpolation interval [%s:%s]" %
(time,self.minTime,self.maxTime)
)
if method == 'linear':
newSV = self._linearOrbitInterpolation(time)
elif method == 'legendre':
newSV = self._legendreOrbitInterpolation(time)
elif method == 'hermite':
newSV = self._hermiteOrbitInterpolation(time)
else:
raise NotImplementedError(
"Orbit interpolation type %s, is not implemented" % method
)
return newSV
## Isn't orbit redundant? -compute the method based on name
def interpolate(self, time, method='linear'):
if time not in self:
raise ValueError("Time stamp (%s) falls outside of the interpolation interval [%s:%s]"
% (time,self.minTime,self.maxTime))
try:
return getattr(self, '_'+method+'OrbitInterpolation')(time)
except AttributeError:
pass
raise NotImplementedError(
"Orbit interpolation type %s, is not implemented" % method
)
interpolateOrbit = interpolate
def _linearOrbitInterpolation(self,time):
"""
Linearly interpolate a state vector. This method returns None if
there are fewer than 2 state vectors in the orbit.
@type time: datetime.datetime
@param time: the time at which to interpolate a state vector
@rtype: Orbit.StateVector
@return: the state vector at the desired time
"""
if len(self) < 2:
self.logger.error("Fewer than 2 state vectors present in orbit, cannot interpolate")
return None
position = [0.0 for i in range(3)]
velocity = [0.0 for i in range(3)]
newOrbit = self.selectStateVectors(time, 1, 1)
obsTime, obsPos, obsVel, offset = newOrbit.to_tuple(
relativeTo=self.minTime
)
dtime = float(DTU.timeDeltaToSeconds(time-offset))
for i in range(3):
position[i] = (obsPos[0][i] +
(obsPos[1][i]-obsPos[0][i])*
(dtime-obsTime[0])/(obsTime[1]-obsTime[0]))
velocity[i] = (obsVel[0][i] +
(obsVel[1][i]-obsVel[0][i])*
(dtime-obsTime[0])/(obsTime[1]-obsTime[0]))
"""
for sv1 in self.stateVectors:
tmp=1.0
for sv2 in self.stateVectors:
if sv1.time == sv2.time:
continue
numerator = float(DTU.timeDeltaToSeconds(sv2.time-time))
denominator = float(
DTU.timeDeltaToSeconds(sv2.time - sv1.time)
)
tmp = tmp*(numerator)/(denominator)
for i in range(3):
position[i] = position[i] + sv1.getPosition()[i]*tmp
velocity[i] = velocity[i] + sv1.getVelocity()[i]*tmp
"""
return StateVector(time=time, position=position, velocity=velocity)
def _legendreOrbitInterpolation(self,time):
"""Interpolate a state vector using an 8th order Legendre polynomial.
This method returns None if there are fewer than 9 state vectors in
the orbit.
@type time: datetime.datetime
@param time: the time at which to interpolate a state vector
@rtype: Orbit.StateVector
@return: the state vector at the desired time
"""
if len(self) < 9:
self.logger.error(
"Fewer than 9 state vectors present in orbit, cannot interpolate"
)
return None
seq = [4,5,3,6,2,7,1,8]
found = False
for ind in seq:
rind = 9 - ind
try:
newOrbit = self.selectStateVectors(time, 4, 5)
found = True
except LookupError as e:
pass
if found:
break
if not found:
raise Exception('Could not find state vectors before/after for interpolation')
obsTime, obsPos, obsVel, offset = newOrbit.to_tuple(
relativeTo=self.minTime
)
t = DTU.timeDeltaToSeconds(time-self.minTime)
t0 = DTU.timeDeltaToSeconds(newOrbit.minTime-self.minTime)
tn = DTU.timeDeltaToSeconds(newOrbit.maxTime-self.minTime)
ansPos = self._legendre8(t0, tn, t, obsPos)
ansVel = self._legendre8(t0, tn, t, obsVel)
return StateVector(time=time, position=ansPos, velocity=ansVel)
def _legendre8(self,t0,tn,t,v):
"""Interpolate an orbit using an 8th order Legendre polynomial
@type t0: float
@param t0: starting time
@type tn: float
@param tn: ending time
@type t: float
@param t: time at which vt must be interpolated
@type v: list
@param v: 9 consecutive points
@rtype: float
@return: interpolated point at time t
"""
trel = (t-t0)/(tn-t0)*(len(v)-1)+1
itrel=max(1,min(int(trel)-4,len(v)-9))+1
t = trel-itrel
vt = [0 for i in range(3)]
kx = 0
x=t+1
noemer = [40320,-5040,1440,-720,576,-720,1440,-5040,40320]
teller=(x)*(x-1)*(x-2)*(x-3)*(x-4)*(x-5)*(x-6)*(x-7)*(x-8)
if (teller == 0):
kx = int(x)
for i in range(3):
vt[i] = v[kx][i]
else:
for kx in range(9):
coeff=teller/noemer[kx]/(x-kx)
for i in range(3):
vt[i] = vt[i] + coeff*v[kx][i]
return vt
def _hermiteOrbitInterpolation(self,time):
"""
Interpolate a state vector using Hermite interpolation.
This method returns None if there are fewer than 4 state
vectors in the orbit.
@type time: datetime.datetime
@param time: the time at which to interpolate a state vector
@rtype: Orbit.StateVector
@return: the state vector at the desired time
"""
import os
from ctypes import c_double, cdll,byref
orbitHermite = (
cdll.LoadLibrary(os.path.dirname(__file__)+'/orbitHermite.so')
)
if len(self) < 4:
self.logger.error(
"Fewer than 4 state vectors present in orbit, cannot interpolate"
)
return None
# The Fortran routine assumes that it is getting an array of four
# state vectors
try:
newOrbit = self.selectStateVectors(time, 2, 2)
except LookupError:
try:
newOrbit = self.selectStateVectors(time,1,3)
except LookupError:
try:
newOrbit = self.selectStateVectors(time,3,1)
except LookupError:
self.logger.error("Unable to select 2 state vectors before and after "+
"chosen time %s" % (time))
return None
# For now, assume that time is an array containing the times at which
# we want to interpolate
obsTime, obsPos, obsVel,offset = newOrbit.to_tuple(
relativeTo=self.minTime
)
td = time - self.minTime
ansTime = DTU.timeDeltaToSeconds(td)
flatObsPos = [item for sublist in obsPos for item in sublist]
flatObsVel = [item for sublist in obsVel for item in sublist]
flatAnsPos= [0.,0.,0.]# list([0.0 for i in range(3)])
flatAnsVel= [0.,0.,0.]#list([0.0 for i in range(3)])
obsTime_C = (c_double*len(obsTime))(*obsTime)
obsPos_C = (c_double*len(flatObsPos))(*flatObsPos)
obsVel_C = (c_double*len(flatObsVel))(*flatObsVel)
ansTime_C = c_double(ansTime)
ansPos_C = (c_double*3)(*flatAnsPos)
ansVel_C = (c_double*3)(*flatAnsVel)
# Use the C wrapper to the fortran Hermite interpolator
orbitHermite.orbitHermite_C(obsPos_C,
obsVel_C,
obsTime_C,
byref(ansTime_C),
ansPos_C,
ansVel_C)
return StateVector(time=time, position=ansPos_C[:], velocity=ansVel_C[:])
## This need to be public -very confusing since there is an __iter__
def to_tuple(self, relativeTo=None):
return self._unpackOrbit(relativeTo=relativeTo)
def _unpackOrbit(self, relativeTo=None):
"""Convert and orbit object into tuple of lists containing time,
position and velocity.
@type relativeTo: datetime.datetime
@param relativeTo: the time with which to reference the unpacked orbit
@return: a tuple containing a list of time, position, velocity and
relative time offset
"""
time = []
position = []
velocity = []
if relativeTo is None:
relativeTo = self.minTime
for sv in self.stateVectors:
td = sv.time - relativeTo
currentTime = ((
td.microseconds +
(td.seconds + td.days * 24 * 3600.0) * 10**6) / 10**6
)
currentPosition = sv.getPosition()
currentVelocity = sv.getVelocity()
time.append(currentTime)
position.append(currentPosition)
velocity.append(currentVelocity)
return time, position, velocity, relativeTo
#def _packOrbit(self,time,position,velocity,relativeTo):
# self._minTime = relativeTo
# self._stateVectors = [];
# for t,p,v in zip(time,position,velocity):
# sv = StateVector(time=relativeTo + datetime.timedelta(seconds=t),position=p,velocity=v)
# self.addStateVector(sv)
## Why does this version fail ERS and not ALOS?
def selectStateVectorsBroken(self, time, before, after):
"""Given a time and a number of before and after state vectors,
return an Orbit with (before+after) state vectors with reference to
time.
@type time: datetime.datetime
@param time: the reference time for subselection
@type before: integer
@param before: the number of state vectors before the chosen time to
select
@type after: integer
@param after: the number of state vectors after the chosen time to
select
@rtype: Orbit.Orbit
@return: an orbit containing (before+after) state vectors relative to
time
@raises LookupError: if there are insufficient state vectors in the
orbit
"""
# First, find the index closest to the requested time
i=0
while self.stateVectors[i].time <= time:
i += 1
beforeIndex = i
# Check that we can grab enough data
if (beforeIndex-before) < 0:
raise LookupError("Requested index %s is out of bounds" %
(beforeIndex-before))
elif (beforeIndex+after) > len(self):
raise LookupError("Requested index %s is out of bounds" %
(beforeIndex+after))
# Create a new orbit object - filled with goodies.
return Orbit(source=self.orbitSource,
quality=self.orbitQuality,
stateVectors=[
self[i] for i in range(
(beforeIndex-before),(beforeIndex+after)
)])
def selectStateVectors(self,time,before,after):
"""
Given a time and a number of before and after state vectors,
return an Orbit with (before+after) state vectors with reference to
time.
"""
# First, find the index closest to the requested time
i=0
while(self._stateVectors[i].getTime() <= time):
i += 1
beforeIndex = i
# Check that we can grab enough data
if ((beforeIndex-before) < 0):
raise LookupError(
"Requested index %s is out of bounds" % (beforeIndex-before)
)
elif ((beforeIndex+after) > len(self._stateVectors)):
raise LookupError(
"Requested index %s is out of bounds" % (beforeIndex+after)
)
# Create a new orbit object
newOrbit = Orbit(name='neworbit')
newOrbit.configure()
# inject dependencies
newOrbit.setOrbitSource(self.orbitSource)
newOrbit.setOrbitQuality(self.orbitQuality)
for i in range((beforeIndex-before),(beforeIndex+after)):
newOrbit.addStateVector(self[i])
return newOrbit
def trimOrbit(self, startTime, stopTime):
"""Trim the list of state vectors to encompass the time span
[startTime:stopTime]
@type startTime: datetime.datetime
@param startTime: the desired starting time for the output orbit
@type stopTime: datetime.datetime
@param stopTime: the desired stopping time for the output orbit
@rtype: Orbit.Orbit
@return: an orbit containing all of the state vectors within the time
span [startTime:stopTime]
"""
newOrbit = Orbit()
newOrbit.configure()
newOrbit.setOrbitSource(self._orbitSource)
newOrbit.setReferenceFrame(self._referenceFrame)
for sv in self._stateVectors:
if startTime < sv.time < stopTime:
newOrbit.addStateVector(sv)
return newOrbit
def _inRange(self,time):
"""Check whether a given time is within the range of values for an
orbit.
@type time: datetime.datetime
@param time: a time
@rtype: boolean
@return: True if the time falls within the time span of the orbit,
otherwise False
"""
return self.minTime <= time <= self.maxTime
def __str__(self):
retstr = "Orbit Source: %s\n"
retlst = (self._orbitSource,)
retstr += "Orbit Quality: %s\n"
retlst += (self._orbitQuality,)
retstr += "Orbit Reference Frame: %s\n"
retlst += (self._referenceFrame,)
return retstr % retlst
stateVector = property()
orbitQuality = property(getOrbitQuality, setOrbitQuality)
orbitSource = property(getOrbitSource, setOrbitSource)
pass
def getHeading(self, time=None, spacing=0.5, planet=None):
'''
Compute heading around given azimuth time.
If time is not provided, mid point of orbit is used.
'''
from isceobj.Planet.Planet import Planet
if planet is None:
planet = Planet(pname='Earth')
refElp = planet.ellipsoid
if time is None:
delta = self.maxTime - self.minTime
aztime = self.minTime + datetime.timedelta(seconds = 0.5 * delta.total_seconds())
else:
aztime = time
t1 = aztime - datetime.timedelta(seconds=spacing)
t2 = aztime + datetime.timedelta(seconds=spacing)
vec1 = self.interpolateOrbit(t1, method='hermite')
vec2 = self.interpolateOrbit(t2, method='hermite')
llh1 = refElp.xyz_to_llh(vec1.getPosition())
llh2 = refElp.xyz_to_llh(vec2.getPosition())
#Heading
hdg = refElp.geo_hdg(llh1, llh2)
return np.degrees(hdg)
def getENUHeading(self, time=None, planet=None):
'''
Compute heading at given azimuth time using single state vector.
If time is not provided, mid point of orbit is used.
'''
from isceobj.Planet.Planet import Planet
if planet is None:
planet = Planet(pname='Earth')
refElp = planet.ellipsoid
if time is None:
delta = self.maxTime - self.minTime
aztime = self.minTime + datetime.timedelta(seconds = 0.5 * delta.total_seconds())
else:
aztime = time
vec1 = self.interpolateOrbit(aztime, method='hermite')
llh1 = refElp.xyz_to_llh(vec1.getPosition())
enumat = refElp.enubasis(llh1)
venu = np.dot(enumat.xyz_to_enu, vec1.getVelocity())
#Heading
hdg = np.arctan2(venu[0,0], venu[0,1])
return np.degrees(hdg)
def rdr2geo(self, aztime, rng, height=0.,
doppler = None, wvl = None,
planet=None, side=-1):
'''
Returns point on ground at given height and doppler frequency.
Never to be used for heavy duty computing.
'''
from isceobj.Planet.Planet import Planet
####Setup doppler for the equations
dopfact = 0.0
hdg = self.getENUHeading(time=aztime)
sv = self.interpolateOrbit(aztime, method='hermite')
pos = sv.getPosition()
vel = sv.getVelocity()
vmag = np.linalg.norm(vel)
if doppler is not None:
dopfact = doppler(DTU.seconds_since_midnight(aztime), rng) * 0.5 * wvl * rng/vmag
if planet is None:
refElp = Planet(pname='Earth').ellipsoid
else:
refElp = planet.ellipsoid
###Convert position and velocity to local tangent plane
satLLH = refElp.xyz_to_llh(pos)
refElp.setSCH(satLLH[0], satLLH[1], hdg)
radius = refElp.pegRadCur
#####Setup ortho normal system right below satellite
satVec = np.array(pos)
velVec = np.array(vel)
###Setup TCN basis
clat = np.cos(np.radians(satLLH[0]))
slat = np.sin(np.radians(satLLH[0]))
clon = np.cos(np.radians(satLLH[1]))
slon = np.sin(np.radians(satLLH[1]))
nhat = np.array([-clat*clon, -clat*slon, -slat])
temp = np.cross(nhat, velVec)
chat = temp / np.linalg.norm(temp)
temp = np.cross(chat, nhat)
that = temp / np.linalg.norm(temp)
vhat = velVec / np.linalg.norm(velVec)
####Solve the range doppler eqns iteratively
####Initial guess
zsch = height
for ii in range(10):
###Near nadir tests
if (satLLH[2]-zsch) >= rng:
return None
a = (satLLH[2] + radius)
b = (radius + zsch)
costheta = 0.5*(a/rng + rng/a - (b/a)*(b/rng))
sintheta = np.sqrt(1-costheta*costheta)
gamma = rng*costheta
alpha = dopfact - gamma*np.dot(nhat,vhat)/np.dot(vhat,that)
beta = -side*np.sqrt(rng*rng*sintheta*sintheta - alpha*alpha)
delta = alpha * that + beta * chat + gamma * nhat
targVec = satVec + delta
targLLH = refElp.xyz_to_llh(list(targVec))
targXYZ = refElp.llh_to_xyz([targLLH[0], targLLH[1], height])
targSCH = refElp.xyz_to_sch(targXYZ)
zsch = targSCH[2]
rdiff = rng - np.linalg.norm(np.array(satVec) - np.array(targXYZ))
return targLLH
def rdr2geoNew(self, aztime, rng, height=0.,
doppler = None, wvl = None,
planet=None, side=-1):
'''
Returns point on ground at given height and doppler frequency.
Never to be used for heavy duty computing.
'''
from isceobj.Planet.Planet import Planet
####Setup doppler for the equations
dopfact = 0.
sv = self.interpolateOrbit(aztime, method='hermite')
pos = np.array(sv.getPosition())
vel =np.array( sv.getVelocity())
vmag = np.linalg.norm(vel)
if doppler is not None:
dopfact = doppler(DTU.seconds_since_midnight(aztime), rng) * 0.5 * wvl * rng/vmag
if planet is None:
refElp = Planet(pname='Earth').ellipsoid
else:
refElp = planet.ellipsoid
###Convert position and velocity to local tangent plane
major = refElp.a
minor = major * np.sqrt(1 - refElp.e2)
#####Setup ortho normal system right below satellite
satDist = np.linalg.norm(pos)
alpha = 1 / np.linalg.norm(pos/ np.array([major, major, minor]))
radius = alpha * satDist
hgt = (1.0 - alpha) * satDist
###Setup TCN basis - Geocentric
nhat = -pos/satDist
temp = np.cross(nhat, vel)
chat = temp / np.linalg.norm(temp)
temp = np.cross(chat, nhat)
that = temp / np.linalg.norm(temp)
vhat = vel / vmag
####Solve the range doppler eqns iteratively
####Initial guess
zsch = height
for ii in range(10):
###Near nadir tests
if (hgt-zsch) >= rng:
return None
a = satDist
b = (radius + zsch)
costheta = 0.5*(a/rng + rng/a - (b/a)*(b/rng))
sintheta = np.sqrt(1-costheta*costheta)
gamma = rng*costheta
alpha = dopfact - gamma*np.dot(nhat,vhat)/np.dot(vhat,that)
beta = -side*np.sqrt(rng*rng*sintheta*sintheta - alpha*alpha)
delta = alpha * that + beta * chat + gamma * nhat
targVec = pos + delta
targLLH = refElp.xyz_to_llh(list(targVec))
targXYZ = np.array(refElp.llh_to_xyz([targLLH[0], targLLH[1], height]))
zsch = np.linalg.norm(targXYZ) - radius
rdiff = rng - np.linalg.norm(pos - targXYZ)
return targLLH
####Make rdr2geo same as pointOnGround
pointOnGround = rdr2geo
def geo2rdr(self, llh, side=-1, planet=None,
doppler=None, wvl=None):
'''
Takes a lat, lon, height triplet and returns azimuth time and range.
Assumes zero doppler for now.
'''
from isceobj.Planet.Planet import Planet
from isceobj.Util.Poly2D import Poly2D
if doppler is None:
doppler = Poly2D()
doppler.initPoly(azimuthOrder=0, rangeOrder=0, coeffs=[[0.]])
wvl = 0.0
if planet is None:
refElp = Planet(pname='Earth'). ellipsoid
else:
refElp = planet.ellipsoid
xyz = refElp.llh_to_xyz(llh)
delta = (self.maxTime - self.minTime).total_seconds() * 0.5
tguess = self.minTime + datetime.timedelta(seconds = delta)
outOfBounds = False
for ii in range(51):
try:
sv = self.interpolateOrbit(tguess, method='hermite')
except:
outOfBounds = True
break
pos = np.array(sv.getPosition())
vel = np.array(sv.getVelocity())
dr = xyz-pos
rng = np.linalg.norm(dr)
dopfact = np.dot(dr,vel)
fdop = doppler(DTU.seconds_since_midnight(tguess),rng) * wvl * 0.5
fdopder = (0.5*wvl*doppler(DTU.seconds_since_midnight(tguess),rng+10.0) - fdop) / 10.0
fn = dopfact - fdop * rng
c1 = -np.dot(vel, vel)
c2 = (fdop/rng + fdopder)
fnprime = c1 + c2 * dopfact
tguess = tguess - datetime.timedelta(seconds = fn/fnprime)
if outOfBounds:
raise Exception('Interpolation time out of bounds')
return tguess, rng
Initial midnight fix
2019-05-06 02:27:36 +00:00
def exportToC(self, reference=None):
Adding all files
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from isceobj.Util import combinedlibmodule
orb = []
Initial midnight fix
2019-05-06 02:27:36 +00:00
###Continue usage as usual if no reference is provided
###This wont break the old interface but could cause
###issues at midnight crossing
if reference is None:
Property is not callable
2019-10-28 22:51:58 +00:00
reference = self.minTime
Initial midnight fix
2019-05-06 02:27:36 +00:00
refEpoch = reference.replace(hour=0, minute=0, second=0, microsecond=0)
Adding all files
2019-01-16 19:40:08 +00:00
for sv in self._stateVectors:
Initial midnight fix
2019-05-06 02:27:36 +00:00
tim = (sv.getTime() - refEpoch).total_seconds()
Adding all files
2019-01-16 19:40:08 +00:00
pos = sv.getPosition()
vel = sv.getVelocity()
row = [tim] + pos + vel
orb.append(row)
cOrbit = combinedlibmodule.exportOrbitToC(1,orb)
return cOrbit
def importFromC(self, ptr, dateobj):
from isceobj.Util import combinedlibmodule
from datetime import timedelta
print('Importing from C')
basis, data = combinedlibmodule.importOrbitFromC(ptr)
for row in data:
sv = StateVector()
sv.setTime( dateobj + timedelta(seconds = row[0]))
sv.setPosition(row[1:4])
sv.setVelocity(row[4:7])
self.addStateVector(sv)
return
def createOrbit():
return Orbit()