insCFGPS

Model GPS readings for insCF sensor fusion

Since R2026a

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    Description

    The insCFGPS object models GPS readings for insCF sensor fusion. When creating an insCF filter object, you can specify an insCFGPS object to enable the filter to use GPS data to correct position.

    Creation

    Syntax

    sensor = insCFGPS
    sensor = insCFGPS(PropertyName=Value)

    Description

    sensor = insCFGPS creates an insCFGPS object. You can specify the insCFGPS object when creating an insCF object to enable the insCF object to fuse GPS data.

    example

    sensor = insCFGPS(PropertyName=Value) sets properties using one or more name-value arguments. For example, ReferenceLocation=[1 1 1] sets the reference location of the GPS sensor model to a latitude of 1 degree, longitude of 1 degree, and altitude of 1 meter.

    example

    Properties

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    Origin of the local navigation reference frame, specified as a three-element row vector of form [latitude longitude altitude], in geodetic coordinates. Altitude is the height above the reference ellipsoid model, WGS84, in meters. Latitude and longitude are in degrees.

    The reference frame is a north-east-down (NED) or east-north-up (ENU) frame, based on the ReferenceFrame property of the insCF object.

    Data Types: single | double

    Examples

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    Open Live Script

    Estimate pose (orientation and position) and velocity from IMU and GPS data by using a complementary filter, represented by an insCF filter object.

    Load the racetrackINSCFDataset.mat file, which contains a timetable with simulated accelerometer, gyroscope, magnetometer, and GPS sensor data for a racetrack-like trajectory, into the workspace. The file also contains the sample rate of the data.

    load("raceTrackINSCFDataset.mat")

    Create an insCF filter object that includes the accelerometer, gyroscope, magnetometer, and GPS sensor objects, as well as an insCFMotionPose motion model object for modeling pose.

    % Sensor object for predicting orientation
gyro = insCFGyroscope;
% Sensor objects for correcting orientation
accel = insCFAccelerometer;
mag = insCFMagnetometer;
% Sensor object for correcting position
gps = insCFGPS(ReferenceLocation=localOrigin);

% Pose motion model
motModel = insCFMotionPose;

% Filter object
filt = insCF(accel,mag,gyro,gps,motModel);

    Specify the initial position, velocity, and orientation from the measurement data.

    % Set initial position
stateparts(filt,"Position",initPos)
% Set initial orientation
stateparts(filt,"Orientation",initOrient)
% Set initial velocity
stateparts(filt,"Velocity",initVel)

    Specify the sensor gains.

    % Set Accelerometer gain
gainparts(filt,"Accelerometer",9.6335e-09)
% Set Magnetometer gain
gainparts(filt,"Magnetometer",0.01)
% Set GPS gain
gainparts(filt,"GPS",0.039246)

    Fuse the sensor data using the filter. The filter estimates pose (orientation and position) and velocity. Extract the estimated position.

    outTT = estimateStates(filt,sensorData);
estPos = outTT.Position;

    Calculate the position RMS error.

    posErr = truePos - estPos; 
pRMS = sqrt(mean(posErr.^2));
fprintf("Position RMS Error:\tX: %.3f, Y: %.3f, Z: %.3f (meters) \n", pRMS(1),pRMS(2),pRMS(3))
    Position RMS Error:	X: 0.372, Y: 0.493, Z: 0.303 (meters)

    Visualize the estimated pose against the ground truth and GPS data.

    figure
plot(truePos(:,1),truePos(:,2),".")
hold on
plot(estPos(:,1),estPos(:,2),"r.-")
gpsLocal = lla2ned(sensorData.GPS,localOrigin,"flat");
plot(gpsLocal(:,1),gpsLocal(:,2),".")

title("Pose Estimate")
legend("Ground Truth","Estimated","GPS")

grid on
xlabel("N (m)")
ylabel("E (m)")
axis equal

    Figure contains an axes object. The axes object with title Pose Estimate, xlabel N (m), ylabel E (m) contains 3 objects of type line. One or more of the lines displays its values using only markers These objects represent Ground Truth, Estimated, GPS.

    Extended Capabilities

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    C/C++ Code Generation
    Generate C and C++ code using MATLAB® Coder™.

    Version History

    Introduced in R2026a

    See Also

    Objects