I want to set my imu noise 0 in gazebo

I am studying VIO slam. I’m using vins fusion. and I am having a problem with imu.

I made an imu in gazebo and i want to set the noise to 0.

The pic below is the imu setting of the gazebo urdf.

<gazebo reference="/imu1_link">
  <sensor name="/imu1" type="imu">
    <pose>0 0 0 0 0 0</pose>
    <plugin filename="libgazebo_ros_imu_sensor.so" name="/imu_plugin">
      <!-- A good description of the IMU parameters can be found in the kalibr documentation:
      https://github.com/ethz-asl/kalibr/wiki/IMU-Noise-Model-and-Intrinsics -->
      <frameName>/imu1_link</frameName> <!-- (string, required): name of the body which holds the IMU sensor -->
      <topicName>/vins_imu</topicName> <!-- (string): name of the sensor output topic and prefix of service names (defaults to imu) -->
      <xyzOffset>0.0 0.0 0.0</xyzOffset>
      <rpyOffset>0.0 0.0 0.0</rpyOffset>


but imu data still have noise.

and if i set the vins fusion imu parameter as 0, its not good work…

so now i set the vins fusion imu parameter :

#Multiple thread support
multiple_thread: 1

#feature traker paprameters
max_cnt: 250 # max feature number in feature tracking
min_dist: 30 # min distance between two features
freq: 10 # frequence (Hz) of publish tracking result. At least 10Hz for good estimation. If set 0, the frequence will be same as raw image
F_threshold: 1.0 # ransac threshold (pixel)
show_track: 1 # publish tracking image as topic
flow_back: 1 # perform forward and backward optical flow to improve feature tracking accuracy

#optimization parameters
max_solver_time: 0.04 # max solver itration time (ms), to guarantee real time
max_num_iterations: 8 # max solver itrations, to guarantee real time
keyframe_parallax: 10.0 # keyframe selection threshold (pixel)

imu parameters The more accurate parameters you provide, the better performance

acc_n: 0.08 # accelerometer measurement noise standard deviation.
gyr_n: 0.004 # gyroscope measurement noise standard deviation.
acc_w: 2.0e-6 # accelerometer bias random work noise standard deviation.
gyr_w: 2.0e-6 # gyroscope bias random work noise standard deviation.
g_norm: 9.81007 # gravity magnitude

but its unstable when doing yaw motions…