422 lines
16 KiB
Python
Executable File
422 lines
16 KiB
Python
Executable File
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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# Copyright 2010 California Institute of Technology. ALL RIGHTS RESERVED.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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# United States Government Sponsorship acknowledged. This software is subject to
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# U.S. export control laws and regulations and has been classified as 'EAR99 NLR'
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# (No [Export] License Required except when exporting to an embargoed country,
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# end user, or in support of a prohibited end use). By downloading this software,
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# the user agrees to comply with all applicable U.S. export laws and regulations.
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# The user has the responsibility to obtain export licenses, or other export
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# authority as may be required before exporting this software to any 'EAR99'
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# embargoed foreign country or citizen of those countries.
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#
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# Author: Giangi Sacco
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#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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import math
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import datetime
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import logging
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from iscesys.Component.Component import Component, Port
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from isceobj.Util.mathModule import MathModule as MM
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from isceobj.Orbit.Orbit import StateVector
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# A class to hold three-dimensional basis vectors
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class Basis(object):
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def __init__(self):
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self.x1 = []
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self.x2 = []
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self.x3 = []
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# A class to hold three-dimensional basis vectors for spacecraft baselines
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class BaselineBasis(Basis):
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def __init__(self):
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Basis.__init__(self)
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def setPositionVector(self,x):
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self.x1 = x
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def getPositionVector(self):
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return self.x1
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def setVelocityVector(self,v):
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self.x2 = v
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def getVelocityVector(self):
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return self.x2
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def setCrossTrackVector(self,c):
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self.x3 = c
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def getCrossTrackVector(self):
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return self.x3
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BASELINE_LOCATION = Component.Parameter('baselineLocation',
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public_name = 'BASELINE_LOCATION',
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default = 'all',
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type=str,
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mandatory=False,
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doc = ('Location at which to compute baselines - "all" implies '+
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'top, middle, bottom of master image, '+
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'"top" implies near start of master image, '+
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'"bottom" implies at bottom of master image, '+
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'"middle" implies near middle of master image. '+
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'To be used in case there is a large shift between images.')
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)
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class Baseline(Component):
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family = 'baseline'
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logging_name = 'isce.mroipac.baseline'
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parameter_list = (BASELINE_LOCATION,)
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# Calculate the Look Angle of the master frame
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def calculateLookAngle(self):
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lookVector = self.calculateLookVector()
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return math.degrees(math.atan2(lookVector[1],lookVector[0]))
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# Calculate the look vector of the master frame
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def calculateLookVector(self):
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try:
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z = self.masterFrame.terrainHeight
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except:
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z = 0.0
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cosl = ((self.height-z)*(2*self.radius + self.height + z) +
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self.startingRange1*self.startingRange1)/(
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2*self.startingRange1*(self.radius + self.height)
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)
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# print('Height: ', self.height)
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# print('Radius: ', self.radius)
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# print('Range: ', self.startingRange1)
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# print('COSL: ', cosl)
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sinl = math.sqrt(1 - cosl*cosl)
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return [cosl,sinl]
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# Calculate the scalar spacecraft velocity
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def calculateScalarVelocity(self,orbit,time):
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sv = orbit.interpolateOrbit(time, method='hermite')
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v = sv.getVelocity()
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normV = MM.norm(v)
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return normV
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# Given an orbit and a time, calculate an orthogonal basis for cross-track and velocity directions
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# based on the spacecraft position
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def calculateBasis(self,orbit,time):
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sv = orbit.interpolateOrbit(time, method='hermite')
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x1 = sv.getPosition()
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v = sv.getVelocity()
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r = MM.normalizeVector(x1) # Turn the position vector into a unit vector
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v = MM.normalizeVector(v) # Turn the velocity vector into a unit vector
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c = MM.crossProduct(r,v) # Calculate the vector perpendicular to the platform position and velocity, this is the c, or cross-track vector
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c = MM.normalizeVector(c)
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v = MM.crossProduct(c,r) # Calculate a the "velocity" component that is perpendicular to the cross-track direction and position
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basis = BaselineBasis()
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basis.setPositionVector(r)
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basis.setVelocityVector(v)
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basis.setCrossTrackVector(c)
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return basis
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# Given two position vectors and a basis, calculate the offset between the two positions in this basis
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def calculateBasisOffset(self,x1,x2,basis):
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dx = [(x2[j] - x1[j]) for j in range(len(x1))] # Calculate the difference between the master and slave position vectors
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z_offset = MM.dotProduct(dx,basis.getVelocityVector()) # Calculate the length of the projection of the difference in position and the "velocity" component
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v_offset = MM.dotProduct(dx,basis.getPositionVector())
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c_offset = MM.dotProduct(dx,basis.getCrossTrackVector())
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return z_offset,v_offset,c_offset
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# Calculate the baseline components between two frames
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def baseline(self):
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#TODO This could be further refactored into a method that calculates the baseline between
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#TODO frames when given a master time and a slave time and a method that calls this method
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#TODO multiple times to calculate the rate of baseline change over time.
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for port in self.inputPorts:
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port()
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lookVector = self.calculateLookVector()
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az_offset = []
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vb = []
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hb = []
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csb = []
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asb = []
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s = [0.,0.,0.]
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if self.baselineLocation.lower() == 'all':
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print('Using entire span of image for estimating baselines')
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masterTime = [self.masterFrame.getSensingStart(),self.masterFrame.getSensingMid(),self.masterFrame.getSensingStop()]
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elif self.baselineLocation.lower() == 'middle':
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print('Estimating baselines around center of master image')
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masterTime = [self.masterFrame.getSensingMid() - datetime.timedelta(seconds=1.0), self.masterFrame.getSensingMid(), self.masterFrame.getSensingMid() + datetime.timedelta(seconds=1.0)]
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elif self.baselineLocation.lower() == 'top':
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print('Estimating baselines at top of master image')
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masterTime = [self.masterFrame.getSensingStart(), self.masterFrame.getSensingStart() + datetime.timedelta(seconds=1.0), self.masterFrame.getSensingStart() + datetime.timedelta(seconds=2.0)]
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elif self.baselineLocation.lower() == 'bottom':
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print('Estimating baselines at bottom of master image')
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masterTime = [self.masterFrame.getSensingStop() - datetime.timedelta(seconds=2.0), self.masterFrame.getSensingStop() - datetime.timedelta(seconds=1.0), self.masterFrame.getSensingStop()]
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else:
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raise Exception('Unknown baseline location: {0}'.format(self.baselineLocation))
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slaveTime = [self.slaveFrame.getSensingMid() - datetime.timedelta(seconds=1.0), self.slaveFrame.getSensingMid(), self.slaveFrame.getSensingMid() + datetime.timedelta(seconds=1.0)]
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# slaveTime = [self.slaveFrame.getSensingStart(),self.slaveFrame.getSensingMid(),self.slaveFrame.getSensingStop()]
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for i in range(3):
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# Calculate the Baseline at the start of the scene, mid-scene, and the end of the scene
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# First, get the position and velocity at the start of the scene
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self.logger.info("Sampling time %s" % i)
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masterBasis = self.calculateBasis(self.masterOrbit,masterTime[i])
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normV = self.calculateScalarVelocity(self.masterOrbit,masterTime[i])
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# Calculate the distance moved since the last baseline point
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if (i > 0):
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deltaT = self._timeDeltaToSeconds(masterTime[i] - masterTime[0])
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s[i] = s[i-1] + deltaT*normV
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masterSV = self.masterOrbit.interpolateOrbit(masterTime[i], method='hermite')
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slaveSV = self.slaveOrbit.interpolateOrbit(slaveTime[i], method='hermite')
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x1 = masterSV.getPosition()
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x2 = slaveSV.getPosition()
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(z_offset,v_offset,c_offset) = self.calculateBasisOffset(x1,x2,masterBasis)
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az_offset.append(z_offset) # Save the position offset
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# Calculate a new start time
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relativeSlaveTime = slaveTime[i] - datetime.timedelta(seconds=(z_offset/normV))
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slaveSV = self.slaveOrbit.interpolateOrbit(relativeSlaveTime, method='hermite')
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# Recalculate the offsets
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x2 = slaveSV.getPosition()
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(z_offset,v_offset,c_offset) = self.calculateBasisOffset(x1,x2,masterBasis)
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vb.append(v_offset)
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hb.append(c_offset)
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csb.append(-hb[i]*lookVector[0] + vb[i]*lookVector[1]) # Multiply the horizontal and vertical baseline components by the look angle vector
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asb.append(-hb[i]*lookVector[1] - vb[i]*lookVector[0])
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#Calculating baseline
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crossTrackBaselinePolynomialCoefficients = self.polynomialFit(s,hb)
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verticalBaselinePolynomialCoefficients = self.polynomialFit(s,vb)
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h_rate = crossTrackBaselinePolynomialCoefficients[1]
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# Calculate the gross azimuth and range offsets
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azb_avg = (az_offset[0] + az_offset[-1])/2.0
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asb_avg = (asb[0] + asb[-1])/2.0
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az_offset = (-azb_avg - h_rate*self.startingRange1*lookVector[1])/(self.azimuthPixelSize)
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r_offset = (self.startingRange1 - self.startingRange2 - asb_avg)/(self.rangePixelSize)
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# Populate class attributes
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self.hBaselineTop = crossTrackBaselinePolynomialCoefficients[0]
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self.hBaselineRate = crossTrackBaselinePolynomialCoefficients[1]
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self.hBaselineAcc = crossTrackBaselinePolynomialCoefficients[2]
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self.vBaselineTop = verticalBaselinePolynomialCoefficients[0]
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self.vBaselineRate = verticalBaselinePolynomialCoefficients[1]
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self.vBaselineAcc = verticalBaselinePolynomialCoefficients[2]
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self.pBaselineTop = csb[0]
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self.pBaselineBottom = csb[-1]
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self.orbSlcAzimuthOffset = az_offset
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self.orbSlcRangeOffset = r_offset
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self.rangeOffset = self.startingRange1 - self.startingRange2
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# Calculate a quadratic fit to the baseline polynomial
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def polynomialFit(self,xRef,yRef):
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size = len(xRef)
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if not (len(xRef) == len(yRef)):
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print("Error. Expecting input vectors of same length.")
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raise Exception
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if not (size == 3):
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print("Error. Expecting input vectors of length 3.")
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raise Exception
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Y = [0]*size
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A = [0]*size
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M = [[0 for i in range(size) ] for j in range(size)]
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for j in range(size):
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for i in range(size):
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M[j][i] = math.pow(xRef[j],i)
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Y[j] = yRef[j]
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MInv = MM.invertMatrix(M)
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for i in range(size):
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for j in range(size):
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A[i] += MInv[i][j]*Y[j]
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return A
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def setRangePixelSize(self,pixelSize):
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self.rangePixelSize = pixelSize
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return
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def setAzimuthPixelSize(self,pixelSize):
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self.azimuthPixelSize = pixelSize
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return
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def setHeight(self,var):
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self.height = float(var)
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return
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def setRadius(self,radius):
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self.radius = radius
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return
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def setMasterStartingRange(self,range):
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self.startingRange1 = range
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return
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def setSlaveStartingRange(self,range):
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self.startingRange2 = range
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return
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def getHBaselineTop(self):
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return self.hBaselineTop
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def getHBaselineRate(self):
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return self.hBaselineRate
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def getHBaselineAcc(self):
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return self.hBaselineAcc
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def getVBaselineTop(self):
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return self.vBaselineTop
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def getVBaselineRate(self):
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return self.vBaselineRate
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def getVBaselineAcc(self):
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return self.vBaselineAcc
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def getPBaselineTop(self):
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return self.pBaselineTop
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def getPBaselineBottom(self):
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return self.pBaselineBottom
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def getOrbSlcAzimuthOffset(self):
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return self.orbSlcAzimuthOffset
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def getOrbSlcRangeOffset(self):
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return self.orbSlcRangeOffset
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def getRangeOffset(self):
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return self.rangeOffset
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def getPhaseConst(self):
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return self.phaseConst
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def getLookAngle(self):
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return self.lookAngle
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def _timeDeltaToSeconds(self,td):
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return (td.microseconds + (td.seconds + td.days * 24.0 * 3600) * 10**6) / 10**6
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def addMasterFrame(self):
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frame = self._inputPorts.getPort(name='masterFrame').getObject()
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self.masterFrame = frame
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self.startingRange1 = frame.getStartingRange()
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prf = frame.getInstrument().getPulseRepetitionFrequency()
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self.rangePixelSize = frame.getInstrument().getRangePixelSize()
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self.masterOrbit = frame.getOrbit()
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midSV = self.masterOrbit.interpolateOrbit(frame.getSensingMid(), method='hermite')
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self.azimuthPixelSize = midSV.getScalarVelocity()/prf
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try:
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ellipsoid = frame._ellipsoid #UAVSAR frame creates ellipsoid with peg
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self.radius = ellipsoid.pegRadCur
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self.height = frame.platformHeight
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except:
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ellipsoid = frame.getInstrument().getPlatform().getPlanet().get_elp()
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self.radius = ellipsoid.get_a()
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self.height = midSV.calculateHeight(ellipsoid)
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def addSlaveFrame(self):
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frame = self._inputPorts.getPort(name='slaveFrame').getObject()
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self.slaveFrame = frame
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self.startingRange2 = frame.getStartingRange()
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self.slaveOrbit = frame.getOrbit()
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def __init__(self, name=''):
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self.masterOrbit = None
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self.slaveOrbit = None
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self.masterFrame = None
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self.slaveFrame = None
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self.lookAngle = None
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self.rangePixelSize = None
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self.azimuthPixelSize = None
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self.height = None
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self.radius = None
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self.startingRange1 = None
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self.startingRange2 = None
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self.hBaselineTop = None
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self.hBaselineRate = None
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self.hBaselineAcc = None
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self.vBaselineTop = None
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self.vBaselineRate = None
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self.vBaselineAcc = None
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self.pBaselineTop = None
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self.pBaselineBottom = None
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self.orbSlcAzimuthOffset = None
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self.orbSlcRangeOffset = None
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self.rangeOffset = None
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self.phaseConst = -99999
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super(Baseline, self).__init__(family=self.__class__.family, name=name)
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self.logger = logging.getLogger('isce.mroipac.baseline')
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self.createPorts()
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# Satisfy the old Component
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self.dictionaryOfOutputVariables = {}
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self.dictionaryOfVariables = {}
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self.descriptionOfVariables = {}
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self.mandatoryVariables = []
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self.optionalVariables = []
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return None
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def createPorts(self):
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# Set input ports
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# It looks like we really need two orbits, a time, range and azimuth pixel sizes
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# the two starting ranges, a planet, and the two prfs
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# These provide the orbits
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# These provide the range and azimuth pixel sizes, starting ranges,
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# satellite heights and times for the first lines
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masterFramePort = Port(name='masterFrame',method=self.addMasterFrame)
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slaveFramePort = Port(name='slaveFrame',method=self.addSlaveFrame)
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self._inputPorts.add(masterFramePort)
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self._inputPorts.add(slaveFramePort)
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return None
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def __str__(self):
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retstr = "Initial Baseline estimates \n"
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retstr += "Cross-track Baseline: %s\n"
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retlst = (self.hBaselineTop,)
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retstr += "Vertical Baseline: %s\n"
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retlst += (self.vBaselineTop,)
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retstr += "Perpendicular Baseline: %s\n"
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retlst += (self.pBaselineTop,)
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retstr += "Bulk Azimuth Offset: %s\n"
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retlst += (self.orbSlcAzimuthOffset,)
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retstr += "Bulk Range Offset: %s\n"
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retlst += (self.orbSlcRangeOffset,)
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return retstr % retlst
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