perturb
Syntax
Description
applies the perturbations defined on the object, offsets
= perturb(obj
)obj
and returns the
offset values. You can define perturbations on the object by using the perturbations
function.
Examples
Perturb Waypoint Trajectory
Define a waypoint trajectory. By default, this trajectory contains two waypoints.
traj = waypointTrajectory
traj = waypointTrajectory with properties: SampleRate: 100 SamplesPerFrame: 1 Waypoints: [2x3 double] TimeOfArrival: [2x1 double] Velocities: [2x3 double] Course: [2x1 double] GroundSpeed: [2x1 double] ClimbRate: [2x1 double] Orientation: [2x1 quaternion] AutoPitch: 0 AutoBank: 0 ReferenceFrame: 'NED'
Define perturbations on the Waypoints
property and the TimeOfArrival
property.
rng(2020); perturbs1 = perturbations(traj,'Waypoints','Normal',1,1)
perturbs1=2×3 table
Property Type Value
_______________ ________ __________________
"Waypoints" "Normal" {[ 1]} {[ 1]}
"TimeOfArrival" "None" {[NaN]} {[NaN]}
perturbs2 = perturbations(traj,'TimeOfArrival','Selection',{[0;1],[0;2]})
perturbs2=2×3 table
Property Type Value
_______________ ___________ _______________________________
"Waypoints" "Normal" {[ 1]} {[ 1]}
"TimeOfArrival" "Selection" {1x2 cell} {[0.5000 0.5000]}
Perturb the trajectory.
offsets = perturb(traj)
offsets=2×1 struct array with fields:
Property
Offset
PerturbedValue
The Waypoints
property and the TimeOfArrival
property have changed.
traj.Waypoints
ans = 2×3
1.8674 1.0203 0.7032
2.3154 -0.3207 0.0999
traj.TimeOfArrival
ans = 2×1
0
2
Perturb Accuracy of insSensor
Create an insSensor
object.
sensor = insSensor
sensor = insSensor with properties: MountingLocation: [0 0 0] m RollAccuracy: 0.2 deg PitchAccuracy: 0.2 deg YawAccuracy: 1 deg PositionAccuracy: [1 1 1] m VelocityAccuracy: 0.05 m/s AccelerationAccuracy: 0 m/s² AngularVelocityAccuracy: 0 deg/s TimeInput: 0 RandomStream: 'Global stream'
Define the perturbation on the RollAccuracy
property as three values with an equal possibility each.
values = {0.1 0.2 0.3}
values=1×3 cell array
{[0.1000]} {[0.2000]} {[0.3000]}
probabilities = [1/3 1/3 1/3]
probabilities = 1×3
0.3333 0.3333 0.3333
perturbations(sensor,'RollAccuracy','Selection',values,probabilities)
ans=7×3 table
Property Type Value
_________________________ ___________ ______________________________________
"RollAccuracy" "Selection" {1x3 cell} {[0.3333 0.3333 0.3333]}
"PitchAccuracy" "None" {[ NaN]} {[ NaN]}
"YawAccuracy" "None" {[ NaN]} {[ NaN]}
"PositionAccuracy" "None" {[ NaN]} {[ NaN]}
"VelocityAccuracy" "None" {[ NaN]} {[ NaN]}
"AccelerationAccuracy" "None" {[ NaN]} {[ NaN]}
"AngularVelocityAccuracy" "None" {[ NaN]} {[ NaN]}
Perturb the sensor
object using the perturb function.
rng(2020) perturb(sensor); sensor
sensor = insSensor with properties: MountingLocation: [0 0 0] m RollAccuracy: 0.5 deg PitchAccuracy: 0.2 deg YawAccuracy: 1 deg PositionAccuracy: [1 1 1] m VelocityAccuracy: 0.05 m/s AccelerationAccuracy: 0 m/s² AngularVelocityAccuracy: 0 deg/s TimeInput: 0 RandomStream: 'Global stream'
The RollAccuracy
is perturbed to 0.5
deg.
Perturb imuSensor
Parameters
Create an imuSensor
object and show its perturbable properties.
imu = imuSensor; perturbations(imu)
ans=17×3 table
Property Type Value
______________________________________ ______ __________________
"Accelerometer.MeasurementRange" "None" {[NaN]} {[NaN]}
"Accelerometer.Resolution" "None" {[NaN]} {[NaN]}
"Accelerometer.ConstantBias" "None" {[NaN]} {[NaN]}
"Accelerometer.NoiseDensity" "None" {[NaN]} {[NaN]}
"Accelerometer.BiasInstability" "None" {[NaN]} {[NaN]}
"Accelerometer.RandomWalk" "None" {[NaN]} {[NaN]}
"Accelerometer.TemperatureBias" "None" {[NaN]} {[NaN]}
"Accelerometer.TemperatureScaleFactor" "None" {[NaN]} {[NaN]}
"Gyroscope.MeasurementRange" "None" {[NaN]} {[NaN]}
"Gyroscope.Resolution" "None" {[NaN]} {[NaN]}
"Gyroscope.ConstantBias" "None" {[NaN]} {[NaN]}
"Gyroscope.NoiseDensity" "None" {[NaN]} {[NaN]}
"Gyroscope.BiasInstability" "None" {[NaN]} {[NaN]}
"Gyroscope.RandomWalk" "None" {[NaN]} {[NaN]}
"Gyroscope.TemperatureBias" "None" {[NaN]} {[NaN]}
"Gyroscope.TemperatureScaleFactor" "None" {[NaN]} {[NaN]}
⋮
Specify the perturbation for the NoiseDensity
property of the accelerometer as a uniform distribution.
perturbations(imu,'Accelerometer.NoiseDensity', ... 'Uniform',1e-5,1e-3);
Specify the perturbation for the RandomWalk
property of the gyroscope as a truncated normal distribution.
perts = perturbations(imu,'Gyroscope.RandomWalk', ... 'TruncatedNormal',2,1e-5,0,Inf);
Load prerecorded IMU data.
load imuSensorData.mat
numSamples = size(orientations);
Simulate the imuSensor
three times with different perturbation realizations.
rng(2021); % For repeatable results numRuns = 3; colors = ['b' 'r' 'g']; for idx = 1:numRuns % Clone IMU to maintain original values imuCopy = clone(imu); % Perturb noise values offsets = perturb(imuCopy); % Obtain the measurements [accelReadings,gyroReadings] = imuCopy(accelerations,angularVelocities,orientations); % Plot the results plot(times,gyroReadings(:,3),colors(idx)); hold on; end xlabel('Time (s)') ylabel('Z-Component of Gyro Readings (rad/s)') legend("First Pass","Second Pass","Third Pass"); hold off
Input Arguments
obj
— Object for perturbation
object
Object for perturbation, specified as an object. The objects that you can perturb include:
Output Arguments
offsets
— Property offsets
array of structure
Property offsets, returned as an array of structures. Each structure contains these fields:
Field Name | Description |
---|---|
Property | Name of perturbed property |
Offset | Offset values applied in the perturbation |
PerturbedValue | Property values after the perturbation |
Version History
Introduced in R2020b
See Also
MATLAB Command
You clicked a link that corresponds to this MATLAB command:
Run the command by entering it in the MATLAB Command Window. Web browsers do not support MATLAB commands.
Select a Web Site
Choose a web site to get translated content where available and see local events and offers. Based on your location, we recommend that you select: .
You can also select a web site from the following list:
How to Get Best Site Performance
Select the China site (in Chinese or English) for best site performance. Other MathWorks country sites are not optimized for visits from your location.
Americas
- América Latina (Español)
- Canada (English)
- United States (English)
Europe
- Belgium (English)
- Denmark (English)
- Deutschland (Deutsch)
- España (Español)
- Finland (English)
- France (Français)
- Ireland (English)
- Italia (Italiano)
- Luxembourg (English)
- Netherlands (English)
- Norway (English)
- Österreich (Deutsch)
- Portugal (English)
- Sweden (English)
- Switzerland
- United Kingdom (English)