82 lines
3.2 KiB
Python
82 lines
3.2 KiB
Python
import numpy as np
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from iscesys.Component.Component import Component, Port
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from isceobj.Orbit.Orbit import Orbit
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import isceobj.Util.geo as geo
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class Make_los(Component):
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def make_los(self):
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"""calculate incidence and squint angles to radar data points"""
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orbit = self._insar.getReferenceOrbit()
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r0 = sensor.getFrame().getStartingRange() # slant range of first pixel
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rsamp = self._insar.getReferenceFrame().getInstrument().rangePixelSize
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asamp = self._insar.getAzimuthPixelSize()
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t0 = self._insar.getReferenceFrame().getSensingStart()
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prf = self._insar.getReferenceFrame().getInstrument().getPulseRepetitionFrequency()
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sc_az_nom = self._insar.getReferenceSquint()
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fd_coef = self._insar.getDopplerCentroid().getDopplerCoefficients()
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wvl = self._insar.getReferenceFrame().getInstrument().getRadarWavelength()
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# get first pos and vel
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sv = orbit.InterpolateOrbit(t0,method='hermite')
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x,y,z = sv.getPosition()
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pos = geo.WGS84.ECEF(x,y,z)
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vx,vy,vz = sv.getVelocity()
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vel = geo.WGS84.ECEF(vx,vy,vz)
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rng = r0 + np.arange(nrmax)*rsamp
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hdg = pos.bearing(pos + vel.hat()*100)
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peg = geo.PegPoint(pos.llh().lat,pos.llh().lon,hdg + sc_az_nom)
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p = pos.sch(peg)
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img_pln_rad = p.ellipsoid.localRad(peg.lat,peg.hdg + hdg)
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trk_rad = p.ellipsoid.localRad(peg.lat,peg.hdg)
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fd_coef_hertz = fd_coef*prf
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spd = float(abs(vel))
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sc_r = float(abs(pos))
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if type_fc == 1:
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rr = rng[nrmax/2]
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pix = (rr - rd_ref)/rsamp_dopp
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dop = np.polyval(fd_coef_hertz,pix)
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th = np.arccos(((p.h + img_pln_rad)**2 + rr**2 - img_pln_rad**2)/(2*rr*(img_pln_rad + p.h)))
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sc_az_nom = lr*(np.pi/2 - np.arcsin(dop*wvl/(2*spd*np.sin(th))))
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else:
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sc_az = np.ones(nrmax)*sc_az_nom
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for i in range(namax):
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nilbuf = np.fromfile(htfile,dtype=float,count=nrmax)
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hgtmap = np.fromfile(htfile,dtype=float,count=nrmax)
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print 'hgtmap',hgtmap
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# load new pos,vel orbit state here
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time = t0 + asamp*i*sc_r/(trk_rad*spd)
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sv = orbit.InterpolateOrbit(time,method='hermite')
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x,y,z = sv.getPosition()
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pos = geo.WGS84.ECEF(x,y,z)
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p = pos.llh()
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if (type_fc == 1):
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pix = (rng - rd_ref)/rsamp_dopp
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dop = np.polyval(fd_coef_hertz,pix)
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th = np.arccos(((p.h + img_pln_rad)**2 + rr**2 - img_pln_rad**2)/(2*rr*(img_pln_rad + p.h)))
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sc_az = lr*(np.pi/2 - np.arcsin(dop*wvl/(2*spd*np.sin(th))))
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target = img_pln_rad + hgtmap
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sc = img_pln_rad + p.h
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look = np.arccos((sc**2 + rng**2 - target**2)/(2*sc*rng))
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beta = np.arccos((sc**2 + target**2 - rng**2)/(2*sc*target))
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inc_angle_rad = look + beta
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inc_angle = np.rad2deg(inc_angle_rad)
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az_angle = np.rad2deg(sc_az) + hdg
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# write out outbuf
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def __init__(self):
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Component.__init__(self)
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self.type_fc = 0
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