def test_azel_to_cart(self):
dec = 7
y = n.array([10.0, 0.0, 0.0])
y_ref = coord.azel_to_cart(90.0, 0.0, 10.0)
nt.assert_array_almost_equal(y, y_ref, decimal=dec)
y = n.array([0.0, 10.0, 0.0])
y_ref = coord.azel_to_cart(0.0, 0.0, 10.0)
nt.assert_array_almost_equal(y, y_ref, decimal=dec)
y = n.array([0.0, 0.0, 10.0])
y_ref = coord.azel_to_cart(0.0, 90.0, 10.0)
nt.assert_array_almost_equal(y, y_ref, decimal=dec)
y = n.array([10.0, 0.0, 10.0])
y_ref = coord.azel_to_cart(90.0, 45.0, n.sqrt(200.0))
nt.assert_array_almost_equal(y, y_ref, decimal=dec)
def point(self, az0, el0):
'''Point beam towards azimuth and elevation coordinate.
:param float az0: Azimuth of pointing direction in dgreees east of north.
:param float el0: Elevation of pointing direction in degrees from horizon.
'''
self.az0 = az0
self.el0 = el0
self.on_axis = coord.azel_to_cart(az0, el0, 1.0)
def __init__(self, gain_func, az0, el0, I_0, f, beam_name=''):
self.I_0 = I_0
self.f = f
self.az0 = az0
self.el0 = el0
self.on_axis = coord.azel_to_cart(az0, el0, 1.0)
self.gain_func = gain_func
self.beam_name = beam_name
def planar_beam(az0, el0, I_0, f, a0, az1, el1):
'''# TODO: Description.
'''
beam = antenna.BeamPattern(planar, az0, el0, I_0, f, beam_name='Planar')
beam.a0 = a0
beam.plane_normal = coord.azel_to_cart(az1, el1, 1.0)
beam.lam = c.c / f
beam.point(az0, el0)
return beam
def angle(self, az, el):
'''Get angle between azimuth and elevation and pointing direction.
:param float az: Azimuth in dgreees east of north to measure from.
:param float el: Elevation in degrees from horizon to measure from.
:return: Angle in degrees.
:rtype: float
'''
direction = coord.azel_to_cart(az, el, 1.0)
return coord.angle_deg(self.on_axis, direction)
def local_pointing(self, t):
'''Returns the instantaneous pointing in local coordinates (ENU).
:param float t: Seconds past a reference epoch to retrieve the pointing at.
'''
point = self._pointing(t)
if self._pointing_coord == 'ned':
k0 = n.array([point[1], point[0], -point[2]], dtype=n.float)
elif self._pointing_coord == 'enu':
k0 = n.array([point[0], point[1], point[2]], dtype=n.float)
elif self._pointing_coord == 'azel':
k0 = coord.azel_to_cart(point[0], point[1], 1.0)
return k0
def plot_gains(beams, res=1000, min_el=0.0, alpha=0.5):
'''Plot the gain of a list of beam patterns as a function of elevation at :math:`0^\circ` degrees azimuth.
:param list beams: List of instances of :class:`antenna.BeamPattern`.
:param int res: Number of points to devide the set elevation range into.
:param float min_el: Minimum elevation in degrees, elevation range is from this number to :math:`90^\circ`.
'''
#turn on TeX interperter
plt.rc('text', usetex=True)
fig = plt.figure(figsize=(15, 7))
ax = fig.add_subplot(111)
theta = n.linspace(min_el, 90.0, num=res)
S = n.zeros((res, len(beams)))
for b, beam in enumerate(beams):
for i, th in enumerate(theta):
k = coord.azel_to_cart(0.0, th, 1.0)
S[i, b] = beam.gain(k)
for b in range(len(beams)):
ax.plot(90 - theta,
n.log10(S[:, b]) * 10.0,
label="Gain " + beams[b].beam_name,
alpha=alpha)
ax.legend()
bottom, top = plt.ylim()
plt.ylim((0, top))
ax.set_xlabel('Zenith angle [deg]', fontsize=24)
plt.xticks(fontsize=17)
plt.yticks(fontsize=17)
ax.set_ylabel('Gain $G$ [dB]', fontsize=24)
ax.set_title('Gain patterns', fontsize=28)
return fig, ax