Skip to content

Commit

Permalink
Refactor tests to simplify sampling LEO and GEO orbits
Browse files Browse the repository at this point in the history
  • Loading branch information
Jason Bernstein committed Sep 24, 2024
1 parent 607aa83 commit 3e2c39f
Show file tree
Hide file tree
Showing 3 changed files with 85 additions and 424 deletions.
43 changes: 43 additions & 0 deletions tests/ssapy_test_helpers.py
View file
Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
import numpy as np
import ssapy


def timer(f):
Expand Down Expand Up @@ -34,3 +35,45 @@ def checkSphere(lon1, lat1, lon2, lat2, atol=1e-14, verbose=False):
if verbose:
print(f"max angle difference {np.rad2deg(np.max(da))*3600} arcsec")
np.testing.assert_allclose(da, 0, rtol=0, atol=atol)


def sample_orbit(t, r_low, r_high, v_low, v_high):
"""
Sample a random orbit by drawing a position vector with magnitude in
(r_low, r_high), a velocity vector with magnitude in (v_low, v_high), and
a direction, at time t.
"""
def sample_vector(lower, upper):
"""
Helper function for sampling a position and velocity vector.
"""
# Sample magnitude of vector
mag = np.random.uniform(lower, upper)
# Sample a random direction (not uniform on sphere)
theta = np.random.uniform(0, 2*np.pi)
phi = np.random.uniform(0, np.pi)
vec_x = mag * np.cos(theta) * np.sin(phi)
vec_y = mag * np.sin(theta) * np.sin(phi)
vec_z = mag * np.cos(phi)
vec = np.array([vec_x, vec_y, vec_z])
return vec

# Sample position and velocity
r = sample_vector(r_low, r_high)
v = sample_vector(v_low, v_high)

return ssapy.Orbit(r, v, t)


def sample_GEO_orbit(t, r_low=4e7, r_high=5e7, v_low=2.7e3, v_high=3.3e3):
"""
Returns a ssapy.Orbit object with a distance near RGEO and a velocity near VGEO.
"""
return sample_orbit(t, r_low, r_high, v_low, v_high)


def sample_LEO_orbit(t, r_low=7e6, r_high=1e7, v_low=7.7e3, v_high=7.9e3):
"""
Returns a ssapy.Orbit object with a position near LEO and a velocity near VLEO.
"""
return sample_orbit(t, r_low, r_high, v_low, v_high)
162 changes: 9 additions & 153 deletions tests/test_accel.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@

import ssapy
from ssapy.utils import norm, iers_interp
from ssapy_test_helpers import timer
from ssapy_test_helpers import timer, sample_LEO_orbit, sample_GEO_orbit

iers_interp(0.0) # Prime the IERS interpolant cache
earth = ssapy.get_body("earth")
Expand Down Expand Up @@ -715,25 +715,7 @@ def test_RK4_vs_analytic():

for _ in range(10):
while True:
# Pick a distance near GEO
r = np.random.uniform(4e7, 5e7)
# Pick a random direction (not uniform on sphere)
theta = np.random.uniform(0, 2*np.pi)
phi = np.random.uniform(0, np.pi)
x = r * np.cos(theta) * np.sin(phi)
y = r * np.sin(theta) * np.sin(phi)
z = r * np.cos(phi)
r = np.array([x, y, z])
# Pick a velocity near VGEO
v = np.random.uniform(2.7e3, 3.3e3)
# and a randomish direction
theta = np.random.uniform(0, 2*np.pi)
phi = np.random.uniform(0, np.pi)
vx = v * np.cos(theta) * np.sin(phi)
vy = v * np.sin(theta) * np.sin(phi)
vz = v * np.cos(phi)
v = np.array([vx, vy, vz])
orbit = ssapy.Orbit(r, v, t0)
orbit = sample_GEO_orbit(t0)
if norm(orbit.periapsis) > 1e7:
break

Expand All @@ -747,25 +729,7 @@ def test_RK4_vs_analytic():
times = t0 + np.linspace(0, 5, 1000)*u.h
for _ in range(10):
while True:
# Repeat near LEO
r = np.random.uniform(7e6, 1e7)
# Pick a random direction (not uniform on sphere)
theta = np.random.uniform(0, 2*np.pi)
phi = np.random.uniform(0, np.pi)
x = r * np.cos(theta) * np.sin(phi)
y = r * np.sin(theta) * np.sin(phi)
z = r * np.cos(phi)
r = np.array([x, y, z])
# Pick a velocity near VLEO
v = np.random.uniform(7.7e3, 7.9e3)
# and a randomish direction
theta = np.random.uniform(0, 2*np.pi)
phi = np.random.uniform(0, np.pi)
vx = v * np.cos(theta) * np.sin(phi)
vy = v * np.sin(theta) * np.sin(phi)
vz = v * np.cos(phi)
v = np.array([vx, vy, vz])
orbit = ssapy.Orbit(r, v, t0.gps)
orbit = sample_LEO_orbit(t0)
if norm(orbit.periapsis) > 6475e3:
break

Expand All @@ -787,25 +751,7 @@ def test_scipy_propagator():

for _ in range(10):
while True:
# Pick a distance near GEO
r = np.random.uniform(4e7, 5e7)
# Pick a random direction (not uniform on sphere)
theta = np.random.uniform(0, 2*np.pi)
phi = np.random.uniform(0, np.pi)
x = r * np.cos(theta) * np.sin(phi)
y = r * np.sin(theta) * np.sin(phi)
z = r * np.cos(phi)
r = np.array([x, y, z])
# Pick a velocity near VGEO
v = np.random.uniform(2.7e3, 3.3e3)
# and a randomish direction
theta = np.random.uniform(0, 2*np.pi)
phi = np.random.uniform(0, np.pi)
vx = v * np.cos(theta) * np.sin(phi)
vy = v * np.sin(theta) * np.sin(phi)
vz = v * np.cos(phi)
v = np.array([vx, vy, vz])
orbit = ssapy.Orbit(r, v, t0)
orbit = sample_GEO_orbit(t0)
if norm(orbit.periapsis) > 1e7:
break

Expand All @@ -819,25 +765,7 @@ def test_scipy_propagator():
times = t0 + np.linspace(0, 5, 1000)*u.h
for _ in range(10):
while True:
# Repeat near LEO
r = np.random.uniform(7e6, 1e7)
# Pick a random direction (not uniform on sphere)
theta = np.random.uniform(0, 2*np.pi)
phi = np.random.uniform(0, np.pi)
x = r * np.cos(theta) * np.sin(phi)
y = r * np.sin(theta) * np.sin(phi)
z = r * np.cos(phi)
r = np.array([x, y, z])
# Pick a velocity near VLEO
v = np.random.uniform(7.7e3, 7.9e3)
# and a randomish direction
theta = np.random.uniform(0, 2*np.pi)
phi = np.random.uniform(0, np.pi)
vx = v * np.cos(theta) * np.sin(phi)
vy = v * np.sin(theta) * np.sin(phi)
vz = v * np.cos(phi)
v = np.array([vx, vy, vz])
orbit = ssapy.Orbit(r, v, t0.gps)
orbit = sample_LEO_orbit(t0)
if norm(orbit.periapsis) > 6475e3:
break

Expand All @@ -860,25 +788,7 @@ def test_RK8():

for _ in range(10):
while True:
# Pick a distance near GEO
r = np.random.uniform(4e7, 5e7)
# Pick a random direction (not uniform on sphere)
theta = np.random.uniform(0, 2*np.pi)
phi = np.random.uniform(0, np.pi)
x = r * np.cos(theta) * np.sin(phi)
y = r * np.sin(theta) * np.sin(phi)
z = r * np.cos(phi)
r = np.array([x, y, z])
# Pick a velocity near VGEO
v = np.random.uniform(2.7e3, 3.3e3)
# and a randomish direction
theta = np.random.uniform(0, 2*np.pi)
phi = np.random.uniform(0, np.pi)
vx = v * np.cos(theta) * np.sin(phi)
vy = v * np.sin(theta) * np.sin(phi)
vz = v * np.cos(phi)
v = np.array([vx, vy, vz])
orbit = ssapy.Orbit(r, v, t0)
orbit = sample_GEO_orbit(t0)
if norm(orbit.periapsis) > 1e7:
break

Expand All @@ -895,25 +805,7 @@ def test_RK8():
times = t0 + np.arange(0, 500)*30*u.s
for _ in range(10):
while True:
# Repeat near LEO
r = np.random.uniform(7e6, 1e7)
# Pick a random direction (not uniform on sphere)
theta = np.random.uniform(0, 2*np.pi)
phi = np.random.uniform(0, np.pi)
x = r * np.cos(theta) * np.sin(phi)
y = r * np.sin(theta) * np.sin(phi)
z = r * np.cos(phi)
r = np.array([x, y, z])
# Pick a velocity near VLEO
v = np.random.uniform(7.7e3, 7.9e3)
# and a randomish direction
theta = np.random.uniform(0, 2*np.pi)
phi = np.random.uniform(0, np.pi)
vx = v * np.cos(theta) * np.sin(phi)
vy = v * np.sin(theta) * np.sin(phi)
vz = v * np.cos(phi)
v = np.array([vx, vy, vz])
orbit = ssapy.Orbit(r, v, t0.gps)
orbit = sample_LEO_orbit(t0)
if norm(orbit.periapsis) > 6475e3:
break

Expand All @@ -939,25 +831,7 @@ def test_RK78():

for _ in range(10):
while True:
# Pick a distance near GEO
r = np.random.uniform(4e7, 5e7)
# Pick a random direction (not uniform on sphere)
theta = np.random.uniform(0, 2*np.pi)
phi = np.random.uniform(0, np.pi)
x = r * np.cos(theta) * np.sin(phi)
y = r * np.sin(theta) * np.sin(phi)
z = r * np.cos(phi)
r = np.array([x, y, z])
# Pick a velocity near VGEO
v = np.random.uniform(2.7e3, 3.3e3)
# and a randomish direction
theta = np.random.uniform(0, 2*np.pi)
phi = np.random.uniform(0, np.pi)
vx = v * np.cos(theta) * np.sin(phi)
vy = v * np.sin(theta) * np.sin(phi)
vz = v * np.cos(phi)
v = np.array([vx, vy, vz])
orbit = ssapy.Orbit(r, v, t0)
orbit = sample_GEO_orbit(t0)
if norm(orbit.periapsis) > 1e7:
break

Expand All @@ -975,25 +849,7 @@ def test_RK78():
times = t0 + np.arange(0, 500)*30*u.s
for _ in range(10):
while True:
# Repeat near LEO
r = np.random.uniform(7e6, 1e7)
# Pick a random direction (not uniform on sphere)
theta = np.random.uniform(0, 2*np.pi)
phi = np.random.uniform(0, np.pi)
x = r * np.cos(theta) * np.sin(phi)
y = r * np.sin(theta) * np.sin(phi)
z = r * np.cos(phi)
r = np.array([x, y, z])
# Pick a velocity near VLEO
v = np.random.uniform(7.7e3, 7.9e3)
# and a randomish direction
theta = np.random.uniform(0, 2*np.pi)
phi = np.random.uniform(0, np.pi)
vx = v * np.cos(theta) * np.sin(phi)
vy = v * np.sin(theta) * np.sin(phi)
vz = v * np.cos(phi)
v = np.array([vx, vy, vz])
orbit = ssapy.Orbit(r, v, t0.gps)
orbit = sample_LEO_orbit(t0)
if norm(orbit.periapsis) > 6475e3:
break

Expand Down
Loading

0 comments on commit 3e2c39f

Please sign in to comment.