#
# ISC License
#
# Copyright (c) 2016, Autonomous Vehicle Systems Lab, University of Colorado at Boulder
#
# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
#
#
# Unit Test Script
# Module Name: celestialTwoBodyPoint
# Author: Mar Cols
# Creation Date: May 11, 2016
#
import inspect
import os
import numpy as np
import pytest
from Basilisk.architecture import messaging
from Basilisk.fswAlgorithms import celestialTwoBodyPoint # module that is to be tested
from Basilisk.utilities import RigidBodyKinematics as rbk
# Import all of the modules that we are going to be called in this simulation
from Basilisk.utilities import SimulationBaseClass
from Basilisk.utilities import astroFunctions as af
from Basilisk.utilities import macros
from Basilisk.utilities import unitTestSupport # general support file with common unit test functions
from Basilisk.utilities import simHelpers
from Basilisk.architecture import astroConstants
from numpy import linalg as la
filename = inspect.getframeinfo(inspect.currentframe()).filename
path = os.path.dirname(os.path.abspath(filename))
textSnippetPassed = r'\textcolor{ForestGreen}{' + "PASSED" + '}'
textSnippetFailed = r'\textcolor{Red}{' + "Failed" + '}'
# uncomment this line is this test is to be skipped in the global unit test run, adjust message as needed
# @pytest.mark.skipif(conditionstring)
# uncomment this line if this test has an expected failure, adjust message as needed
# @pytest.mark.xfail(conditionstring)
# provide a unique test method name, starting with test_
[docs]
def computeCelestialTwoBodyPoint(R_P1, v_P1, a_P1, R_P2, v_P2, a_P2):
"""Compute analytic truth from relative states expressed in N-frame components."""
# Beforehand computations
R_n = np.cross(R_P1, R_P2)
v_n = np.cross(v_P1, R_P2) + np.cross(R_P1, v_P2)
a_n = np.cross(a_P1, R_P2) + np.cross(R_P1, a_P2) + 2 * np.cross(v_P1, v_P2)
# Reference Frame generation
r1_hat = R_P1/la.norm(R_P1)
r3_hat = R_n/la.norm(R_n)
r2_hat = np.cross(r3_hat, r1_hat)
RN = np.array([r1_hat, r2_hat, r3_hat])
sigma_RN = rbk.C2MRP(RN)
# Reference base-vectors first time-derivative
I_33 = np.identity(3)
C1 = I_33 - np.outer(r1_hat, r1_hat)
dr1_hat = 1.0 / la.norm(R_P1) * np.dot(C1, v_P1)
C3 = I_33 - np.outer(r3_hat, r3_hat)
dr3_hat = 1.0 / la.norm(R_n) * np.dot(C3, v_n)
dr2_hat = np.cross(dr3_hat, r1_hat) + np.cross(r3_hat, dr1_hat)
# Angular Velocity computation
omega_RN_R = np.array([
np.dot(r3_hat, dr2_hat),
np.dot(r1_hat, dr3_hat),
np.dot(r2_hat, dr1_hat)
])
omega_RN_N = np.dot(RN.T, omega_RN_R)
# Reference base-vectors second time-derivative
temp33_1 = 2 * np.outer(dr1_hat, r1_hat) + np.outer(r1_hat, dr1_hat)
ddr1_hat = 1.0 / la.norm(R_P1) * (np.dot(C1, a_P1) - np.dot(temp33_1, v_P1))
temp33_3 = 2 * np.outer(dr3_hat, r3_hat) + np.outer(r3_hat, dr3_hat)
ddr3_hat = 1.0 / la.norm(R_n) * (np.dot(C3, a_n) - np.dot(temp33_3, v_n))
ddr2_hat = np.cross(ddr3_hat, r1_hat) + np.cross(r3_hat, ddr1_hat) + 2 * np.cross(dr3_hat, dr1_hat)
# Angular Acceleration computation
domega_RN_R = np.array([
np.dot(dr3_hat, dr2_hat) + np.dot(r3_hat, ddr2_hat),
np.dot(dr1_hat, dr3_hat) + np.dot(r1_hat, ddr3_hat),
np.dot(dr2_hat, dr1_hat) + np.dot(r2_hat, ddr1_hat)
])
domega_RN_N = np.dot(RN.T, domega_RN_R)
return sigma_RN, omega_RN_N, domega_RN_N
[docs]
@pytest.mark.parametrize("secondary_mode", ["moving", "absent", "parallel", "antiparallel"])
@pytest.mark.parametrize("sample_time", [0.0, 250.0]) # [s]
def test_reference_derivatives(secondary_mode, sample_time):
"""Check the published rate and acceleration with central finite differences.
Bodies follow straight-line trajectories, consistent with the module's
zero-relative-acceleration assumption. The moving-secondary case reproduces
issue 1618. The remaining cases exercise the fallback reference with an
absent, parallel, or antiparallel secondary direction. Each case is sampled
at two times with a reference frame that is not aligned with N.
Differentiate the output attitude basis to check ``omega_RN_N``, then
differentiate the output rate to check ``domega_RN_N``. Neither check uses
the analytic truth helper or the module's acceleration equations.
"""
primary_position_N = np.array([7e6, 1e6, -2e6]) # [m]
primary_velocity_N = np.array([-1e3, 7e3, 2e3]) # [m/s]
secondary_position_N = np.array([-3e6, 8e6, 4e6]) # [m]
secondary_velocity_N = np.array([5e3, 1e3, -3e3]) # [m/s]
step = 0.1 # [s]
rate_tolerance = 1e-11 # [rad/s]
acceleration_tolerance = 1e-13 # [rad/s^2]
module = celestialTwoBodyPoint.celestialTwoBodyPoint()
module.ModelTag = "referenceDerivativeCheck"
module.singularityThresh = np.deg2rad(1.0) # [rad]
nav_message = messaging.NavTransMsg().write(messaging.NavTransMsgPayload())
primary_message = messaging.EphemerisMsg()
secondary_message = messaging.EphemerisMsg()
module.transNavInMsg.subscribeTo(nav_message)
module.celBodyInMsg.subscribeTo(primary_message)
if secondary_mode != "absent":
module.secCelBodyInMsg.subscribeTo(secondary_message)
module.SelfInit()
module.Reset(0)
def evaluate(time):
"""Return reference outputs for the body states at ``time`` in seconds."""
primary_data = messaging.EphemerisMsgPayload()
primary_data.r_BdyZero_N = primary_position_N + time * primary_velocity_N
primary_data.v_BdyZero_N = primary_velocity_N
primary_message.write(primary_data)
if secondary_mode != "absent":
secondary_data = messaging.EphemerisMsgPayload()
if secondary_mode == "moving":
secondary_data.r_BdyZero_N = secondary_position_N + time * secondary_velocity_N
secondary_data.v_BdyZero_N = secondary_velocity_N
else:
scale = 2.0 if secondary_mode == "parallel" else -2.0 # [-]
secondary_data.r_BdyZero_N = scale * np.array(primary_data.r_BdyZero_N)
secondary_data.v_BdyZero_N = scale * primary_velocity_N
secondary_message.write(secondary_data)
# The algorithm is instantaneous; sample time is carried by the input states.
module.UpdateState(0)
output = module.attRefOutMsg.read()
return (rbk.MRP2C(output.sigma_RN), np.array(output.omega_RN_N),
np.array(output.domega_RN_N))
dcm_minus, omega_minus_N, _ = evaluate(sample_time - step)
dcm_RN, omega_RN_N, domega_RN_N = evaluate(sample_time)
dcm_plus, omega_plus_N, _ = evaluate(sample_time + step)
dcm_dot = (dcm_plus - dcm_minus) / (2 * step)
omega_difference_N = 0.5 * np.sum(np.cross(dcm_RN, dcm_dot), axis=0)
acceleration_difference_N = (omega_plus_N - omega_minus_N) / (2 * step)
np.testing.assert_allclose(omega_RN_N, omega_difference_N, rtol=0, atol=rate_tolerance)
np.testing.assert_allclose(
domega_RN_N, acceleration_difference_N, rtol=0, atol=acceleration_tolerance
)
[docs]
def test_celestialTwoBodyPointTestFunction(show_plots):
"""Module Unit Test"""
[testResults, testMessage] = celestialTwoBodyPointTestFunction(show_plots)
assert testResults < 1, testMessage
def celestialTwoBodyPointTestFunction(show_plots):
testFailCount = 0 # zero unit test result counter
testMessages = [] # create empty array to store test log messages
unitTaskName = "unitTask" # arbitrary name (don't change)
unitProcessName = "TestProcess" # arbitrary name (don't change)
# Create a sim module as an empty container
unitTestSim = SimulationBaseClass.SimBaseClass()
# Create test thread
testProcessRate = macros.sec2nano(0.5) # update process rate update time
testProc = unitTestSim.CreateNewProcess(unitProcessName)
testProc.addTask(unitTestSim.CreateNewTask(unitTaskName, testProcessRate))
# Construct algorithm and associated C++ container
module = celestialTwoBodyPoint.celestialTwoBodyPoint()
module.ModelTag = "celestialTwoBodyPoint"
# Add test module to runtime call list
unitTestSim.AddModelToTask(unitTaskName, module)
# Initialize the test module configuration data
module.singularityThresh = 1.0 * macros.D2R
# Previous Computation of Initial Conditions for the test
a = astroConstants.REQ_EARTH * 2.8 * 1000 # m
e = 0.0
i = 0.0
Omega = 0.0
omega = 0.0
f = 60 * macros.D2R
(r, v) = af.OE2RV(astroConstants.MU_EARTH*1e9, a, e, i, Omega, omega, f)
r_BN_N = np.array([0., 0., 0.])
v_BN_N = np.array([0., 0., 0.])
celPositionVec = r
celVelocityVec = v
# Create input message and size it because the regular creator of that message
# is not part of the test.
# Navigation Input Message
NavStateOutData = messaging.NavTransMsgPayload() # Create a structure for the input message
NavStateOutData.r_BN_N = r_BN_N
NavStateOutData.v_BN_N = v_BN_N
navMsg = messaging.NavTransMsg().write(NavStateOutData)
# Spice Input Message of Primary Body
CelBodyData = messaging.EphemerisMsgPayload()
CelBodyData.r_BdyZero_N = celPositionVec
CelBodyData.v_BdyZero_N = celVelocityVec
celBodyMsg = messaging.EphemerisMsg().write(CelBodyData)
# Setup logging on the test module output message so that we get all the writes to it
dataLog = module.attRefOutMsg.recorder()
unitTestSim.AddModelToTask(unitTaskName, dataLog)
# connect messages
module.transNavInMsg.subscribeTo(navMsg)
module.celBodyInMsg.subscribeTo(celBodyMsg)
# Need to call the self-init and cross-init methods
unitTestSim.InitializeSimulation()
# Set the simulation time.
# NOTE: the total simulation time may be longer than this value. The
# simulation is stopped at the next logging event on or after the
# simulation end time.
unitTestSim.ConfigureStopTime(macros.sec2nano(1.)) # seconds to stop simulation
# Begin the simulation time run set above
unitTestSim.ExecuteSimulation()
## Set truth values
a = astroConstants.REQ_EARTH * 2.8 * 1000 # m
e = 0.0
i = 0.0
Omega = 0.0
omega = 0.0
f = 60 * macros.D2R
mu = astroConstants.MU_EARTH*1e9 # m^3/s^2
(r, v) = af.OE2RV(mu, a, e, i, Omega, omega, f)
r_BN_N = np.array([0., 0., 0.])
v_BN_N = np.array([0., 0., 0.])
celPositionVec = r
celVelocityVec = v
# Begin Method
R_P1 = celPositionVec - r_BN_N
v_P1 = celVelocityVec - v_BN_N
a_P1 = np.array([0., 0., 0.])
R_P2 = np.cross(R_P1, v_P1)
v_P2 = np.cross(R_P1, a_P1)
a_P2 = np.cross(v_P1, a_P1)
sigma_RN, omega_RN_N, domega_RN_N = computeCelestialTwoBodyPoint(R_P1, v_P1, a_P1, R_P2, v_P2, a_P2)
# This pulls the actual data log from the simulation run.
# Note that range(3) will provide [0, 1, 2] Those are the elements you get from the vector (all of them)
# check sigma_RN
moduleOutput = dataLog.sigma_RN
# compare the module results to the truth values
accuracy = 1e-12
# check a vector values
for i in range(0, len(moduleOutput)):
if not unitTestSupport.isArrayEqual(moduleOutput[i], sigma_RN, 3, accuracy):
testFailCount += 1
testMessages.append("FAILED: " + module.ModelTag + " Module failed sigma_RN unit test at t=" +
str(moduleOutput[i, 0] * macros.NANO2SEC) +
"sec\n")
simHelpers.writeTeXSnippet('passFail11', textSnippetFailed, path)
else:
simHelpers.writeTeXSnippet('passFail11', textSnippetPassed, path)
# check omega_RN_N
moduleOutput = dataLog.omega_RN_N
# compare the module results to the truth values
# check a vector values
for i in range(0, len(moduleOutput)):
if not unitTestSupport.isArrayEqual(moduleOutput[i], omega_RN_N, 3, accuracy):
testFailCount += 1
testMessages.append("FAILED: " + module.ModelTag + " Module failed omega_RN_N unit test at t=" +
str(moduleOutput[i, 0] * macros.NANO2SEC) +
"sec\n")
simHelpers.writeTeXSnippet('passFail12', textSnippetFailed, path)
else:
simHelpers.writeTeXSnippet('passFail12', textSnippetPassed, path)
# check domega_RN_N
moduleOutput = dataLog.domega_RN_N
# compare the module results to the truth values
# check a vector values
for i in range(0, len(moduleOutput)):
if not unitTestSupport.isArrayEqual(moduleOutput[i], domega_RN_N, 3, accuracy):
testFailCount += 1
testMessages.append("FAILED: " + module.ModelTag + " Module failed domega_RN_N unit test at t=" +
str(moduleOutput[i, 0] * macros.NANO2SEC) +
"sec\n")
simHelpers.writeTeXSnippet('passFail13', textSnippetFailed, path)
else:
simHelpers.writeTeXSnippet('passFail13', textSnippetPassed, path)
if testFailCount == 0:
print("PASSED: " + "celestialTwoBodyPointTestFunction")
else:
print(testMessages)
return [testFailCount, ''.join(testMessages)]
[docs]
def test_secBodyCelestialTwoBodyPointTestFunction(show_plots):
"""Module Unit Test"""
# each test method requires a single assert method to be called
[testResults, testMessage] = secBodyCelestialTwoBodyPointTestFunction(show_plots)
assert testResults < 1, testMessage
def secBodyCelestialTwoBodyPointTestFunction(show_plots):
testFailCount = 0 # zero unit test result counter
testMessages = [] # create empty array to store test log messages
unitTaskName = "unitTask" # arbitrary name (don't change)
unitProcessName = "TestProcess" # arbitrary name (don't change)
# Create a sim module as an empty container
unitTestSim = SimulationBaseClass.SimBaseClass()
# Create test thread
testProcessRate = macros.sec2nano(0.5) # update process rate update time
testProc = unitTestSim.CreateNewProcess(unitProcessName)
testProc.addTask(unitTestSim.CreateNewTask(unitTaskName, testProcessRate))
# Construct algorithm and associated C++ container
module = celestialTwoBodyPoint.celestialTwoBodyPoint()
module.ModelTag = "secBodyCelestialTwoBodyPoint"
# Add test module to runtime call list
unitTestSim.AddModelToTask(unitTaskName, module)
# Initialize the test module configuration data
module.singularityThresh = 1.0 * macros.D2R
# Previous Computation of Initial Conditions for the test
a = astroConstants.REQ_EARTH * 2.8 * 1000 # m
e = 0.0
i = 0.0
Omega = 0.0
omega = 0.0
f = 60 * macros.D2R
mu = astroConstants.MU_EARTH*1e9 # m^3/s^2
(r, v) = af.OE2RV(mu, a, e, i, Omega, omega, f)
r_BN_N = np.array([0., 0., 0.])
v_BN_N = np.array([0., 0., 0.])
celPositionVec = r
celVelocityVec = v
# Create input message and size it because the regular creator of that message
# is not part of the test.
# Navigation Input Message
NavStateOutData = messaging.NavTransMsgPayload() # Create a structure for the input message
NavStateOutData.r_BN_N = r_BN_N
NavStateOutData.v_BN_N = v_BN_N
navMsg = messaging.NavTransMsg().write(NavStateOutData)
# Spice Input Message of Primary Body
CelBodyData = messaging.EphemerisMsgPayload()
CelBodyData.r_BdyZero_N = celPositionVec
CelBodyData.v_BdyZero_N = celVelocityVec
celBodyMsg = messaging.EphemerisMsg().write(CelBodyData)
# Spice Input Message of Secondary Body
SecBodyData = messaging.EphemerisMsgPayload()
secPositionVec = [500., 500., 500.]
SecBodyData.r_BdyZero_N = secPositionVec
secVelocityVec = [0., 0., 0.]
SecBodyData.v_BdyZero_N = secVelocityVec
cel2ndBodyMsg = messaging.EphemerisMsg().write(SecBodyData)
# Setup logging on the test module output message so that we get all the writes to it
dataLog = module.attRefOutMsg.recorder()
unitTestSim.AddModelToTask(unitTaskName, dataLog)
# connect messages
module.transNavInMsg.subscribeTo(navMsg)
module.celBodyInMsg.subscribeTo(celBodyMsg)
module.secCelBodyInMsg.subscribeTo(cel2ndBodyMsg)
# Need to call the self-init and cross-init methods
unitTestSim.InitializeSimulation()
# Set the simulation time.
# NOTE: the total simulation time may be longer than this value. The
# simulation is stopped at the next logging event on or after the
# simulation end time.
unitTestSim.ConfigureStopTime(macros.sec2nano(1.)) # seconds to stop simulation
# Begin the simulation time run set above
unitTestSim.ExecuteSimulation()
# This pulls the actual data log from the simulation run.
# Note that range(3) will provide [0, 1, 2] Those are the elements you get from the vector (all of them)
# check sigma_RN
moduleOutput = dataLog.sigma_RN
# set the filtered output truth states
trueVector = [0.474475084038, 0.273938317493, 0.191443718765]
# compare the module results to the truth values
accuracy = 1e-10
simHelpers.writeTeXSnippet("toleranceValue", str(accuracy), path)
for i in range(0, len(moduleOutput)):
# check a vector values
if not unitTestSupport.isArrayEqual(moduleOutput[i], trueVector, 3, accuracy):
testFailCount += 1
testMessages.append("FAILED: " + module.ModelTag + " Module failed sigma_RN unit test at t=" +
str(dataLog.times()[i] * macros.NANO2SEC) +
"sec\n")
simHelpers.writeTeXSnippet('passFail21', textSnippetFailed, path)
else:
simHelpers.writeTeXSnippet('passFail21', textSnippetPassed, path)
# check omega_RN_N
moduleOutput = dataLog.omega_RN_N
# set the filtered output truth states
trueVector = [1.59336987e-04, 2.75979758e-04, 2.64539877e-04]
# compare the module results to the truth values
for i in range(0, len(moduleOutput)):
# check a vector values
if not unitTestSupport.isArrayEqual(moduleOutput[i], trueVector, 3, accuracy):
testFailCount += 1
testMessages.append("FAILED: " + module.ModelTag + " Module failed omega_RN_N unit test at t=" +
str(dataLog.times()[i] * macros.NANO2SEC) +
"sec\n")
simHelpers.writeTeXSnippet('passFail22', textSnippetFailed, path)
else:
simHelpers.writeTeXSnippet('passFail22', textSnippetPassed, path)
# check domega_RN_N
moduleOutput = dataLog.domega_RN_N
# Analytic result, also checked by finite differences of the reference rate.
trueVector = [-1.2147297051129594e-07, -4.1793434670048644e-08, 0.0] # [rad/s^2]
# compare the module results to the truth values
for i in range(0, len(moduleOutput)):
# check a vector values
if not unitTestSupport.isArrayEqual(moduleOutput[i], trueVector, 3, accuracy):
testFailCount += 1
testMessages.append("FAILED: " + module.ModelTag + " Module failed domega_RN_N unit test at t=" +
str(dataLog.times()[i] * macros.NANO2SEC) +
"sec\n")
simHelpers.writeTeXSnippet('passFail23', textSnippetFailed, path)
else:
simHelpers.writeTeXSnippet('passFail23', textSnippetPassed, path)
# Note that we can continue to step the simulation however we feel like.
# Just because we stop and query data does not mean everything has to stop for good
unitTestSim.ConfigureStopTime(macros.sec2nano(0.6)) # run an additional 0.6 seconds
unitTestSim.ExecuteSimulation()
if testFailCount == 0:
print("PASSED: " + "secBodyCelestialTwoBodyPointTestFunction")
else:
print(testMessages)
# each test method requires a single assert method to be called
# this check below just makes sure no sub-test failures were found
return [testFailCount, ''.join(testMessages)]
#
# This statement below ensures that the unitTestScript can be run as a
# stand-along python script
#
if __name__ == "__main__":
# celestialTwoBodyPointTestFunction(False)
secBodyCelestialTwoBodyPointTestFunction(False)