def testSCHDOT(self):
elp = Planet("Earth").get_elp()
elp.setSCH(0., 0., 90.)
sch = [0., 0., 0.]
schdot = [0., 0., 10.]
xyz, xyzdot = elp.schdot_to_xyzdot(sch, schdot)
ans = [10.0, 0.0, 0.0]
for (x, x1) in zip(xyzdot, ans):
self.assertAlmostEqual(x, x1, places=3)
xyz = [elp.a, 0., 0.]
sch1, schdot1 = elp.xyzdot_to_schdot(xyz, xyzdot)
for (s, s1) in zip(schdot, schdot1):
self.assertAlmostEqual(s, s1, places=3)
elp.setSCH(30., 60., 30.)
sch = [0., 0., 0.]
schdot = [10., 0., 0.]
xyz, xyzdot = elp.schdot_to_xyzdot(sch, schdot)
ans = [-6.495190528383289, -1.2499999999999996, 7.500000000000001]
for (x, x1) in zip(xyzdot, ans):
self.assertAlmostEqual(x, x1, places=3)
xyz = elp.sch_to_xyz(sch)
sch1, schdot1 = elp.xyzdot_to_schdot(xyz, xyzdot)
for (s, s1) in zip(schdot, schdot1):
self.assertAlmostEqual(s, s1, places=3)
def testConvertSCHdot(self):
elp = Planet("Earth").get_elp()
elp.setSCH(66.0, -105.0, 36.0)
#From for_ellipsoid_test.F
#convert_schdot_to_xyzdot, sch_to_xyz
r_sch = [1468.0, -234.0, 7000.0]
r_schdot = [800.0, -400.0, 100.0]
r_xyz = [-672788.46258740244, -2514950.4839521507, 5810769.7976823179]
r_xyzdot = [853.73728655948685, 118.98447071885982, 258.79594191185748]
posXYZ, velXYZ = elp.schdot_to_xyzdot(r_sch, r_schdot)
for (a, b) in zip(r_xyz, posXYZ):
self.assertAlmostEqual(a, b, places=3)
for (a, b) in zip(r_xyzdot, velXYZ):
self.assertAlmostEqual(a, b, places=3)
#convert_schdot_to_xyzdot, xyz_to_sch
r_xyz = [-672100.0, -2514000.0, 5811000.0]
r_xyzdot = [800.0, -400.0, 100.0]
r_sch = [2599.1237664792707, 70.396218844576666, 6764.7576835183427]
r_schdot = [
415.39842327248573, -781.28909619852459, 164.41258499283407
]
posSCH, velSCH = elp.xyzdot_to_schdot(r_xyz, r_xyzdot)
for (a, b) in zip(r_sch, posSCH):
self.assertAlmostEqual(a, b, places=3)
for (a, b) in zip(r_schdot, velSCH):
self.assertAlmostEqual(a, b, delta=0.1)
def numberOfLooks(self, frame, posting, azlooks, rglooks):
'''
Compute relevant number of looks.
'''
from isceobj.Planet.Planet import Planet
from isceobj.Constants import SPEED_OF_LIGHT
import numpy as np
azFinal = None
rgFinal = None
if azlooks is not None:
azFinal = azlooks
if rglooks is not None:
rgFinal = rglooks
if (azFinal is not None) and (rgFinal is not None):
return (azFinal, rgFinal)
if posting is None:
raise Exception('Input posting is none. Either specify (azlooks, rglooks) or posting in input file')
elp = Planet(pname='Earth').ellipsoid
####First determine azimuth looks
tmid = frame.sensingMid
sv = frame.orbit.interpolateOrbit( tmid, method='hermite') #.getPosition()
llh = elp.xyz_to_llh(sv.getPosition())
if azFinal is None:
hdg = frame.orbit.getENUHeading(tmid)
elp.setSCH(llh[0], llh[1], hdg)
sch, vsch = elp.xyzdot_to_schdot(sv.getPosition(), sv.getVelocity())
azFinal = max(int(np.round(posting * frame.PRF / vsch[0])), 1)
if rgFinal is None:
pulseLength = frame.instrument.pulseLength
chirpSlope = frame.instrument.chirpSlope
#Range Bandwidth
rBW = np.abs(chirpSlope)*pulseLength
# Slant Range resolution
rgres = abs(SPEED_OF_LIGHT / (2.0 * rBW))
r0 = frame.startingRange
rmax = frame.getFarRange()
rng =(r0+rmax)/2
Re = elp.pegRadCur
H = sch[2]
cos_beta_e = (Re**2 + (Re + H)**2 -rng**2)/(2*Re*(Re+H))
sin_bet_e = np.sqrt(1 - cos_beta_e**2)
sin_theta_i = sin_bet_e*(Re + H)/rng
print("incidence angle at the middle of the swath: ", np.arcsin(sin_theta_i)*180.0/np.pi)
groundRangeRes = rgres/sin_theta_i
print("Ground range resolution at the middle of the swath: ", groundRangeRes)
rgFinal = max(int(np.round(posting/groundRangeRes)),1)
return azFinal, rgFinal
