Robot localization:using 3 sensors(wheel encoder,imu,gps) in curves we are getting drifts in output

edit

Hi Everyone,

I am using robot localization package to fuse 1 wheel encoder,1 imu and 1 gps.

1. For doing localization , I am using 1 state estimation node(ukf) inputs: encoder(/odom/data),imu(imu/data), gps(odometry/gps). output: odometry/filtered
2. navsat_transform_node inputs:gps(/fix1) output: odometry/gps

I am able to get output for this configuration but the problem is whenever i am running these nodes in curverd path it is showing drift.

In straight path ,the output is as expected.

1. I want to know how to solve this issue in curved path and at the end.
2. I want to know why static transform is required , i m giving yaw(starting heading of robot) manually here but it ll change
   everytime what can i do to do that automatic.
   1. Please view the launch and yaml file and suggest us what can we do to correct the issue.

edited-

The input messages for sensors used are,

odometry data(topic:/odom/data)

header: 
  seq: 18
  stamp: 
    secs: 1543233105
    nsecs: 933596449
  frame_id: "odom"
child_frame_id: "base_link"
pose: 
  pose: 
    position: 
      x: 0.0
      y: 0.0
      z: 0.0
    orientation: 
      x: 0.0
      y: 0.0
      z: 0.0
      w: 0.0
  covariance: [0.001, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.001, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.001, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.001, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.001, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.03]
twist: 
  twist: 
    linear: 
      x: 0.0147113889434
      y: 0.0
      z: 0.0
    angular: 
      x: 0.0
      y: 0.0
      z: -0.00374101494052
  covariance: [0.001, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.001, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.001, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.001, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.001, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.03]

IMU data(topic:/imu/data)

header: 
  seq: 313
  stamp: 
    secs: 21
    nsecs: 484000000
  frame_id: "imu_link"
orientation: 
  x: 5.24012097576e-05
  y: 0.000117985712522
  z: -0.988258955695
  w: 0.152788153412
orientation_covariance: [0.001225, 0.0, 0.0, 0.0, 0.001225, 0.0, 0.0, 0.0, 0.001225]
angular_velocity: 
  x: 0.0
  y: 0.0
  z: 0.0
angular_velocity_covariance: [0.0004, 0.0, 0.0, 0.0, 0.0004, 0.0, 0.0, 0.0, 0.0004]
linear_acceleration: 
  x: 0.0310470898156
  y: -0.00114743773105
  z: 9.7057897167
linear_acceleration_covariance: [0.009604, 0.0, 0.0, 0.0, 0.009604, 0.0, 0.0, 0.0, 0.009604]

GPS data(topic:/fix1)

header: 
  seq: 4
  stamp: 
    secs: 23
    nsecs:   4000000
  frame_id: "gps"
status: 
  status: 1
  service: 1
latitude: 49.8548095709
longitude: 8.59120397786
altitude: 0.92988040448 ...