robot_localization : no output from navsat_transform on odometry/gps

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Hi, I have a bag file which has IMU, GPS and wheel odometry and I'm trying to fuse it through robot_localization. I have followed everything as per the document. the ekf node is working fine but there is no output on the topic odometry/gps. I am manually tuning the covariance values for all the three sensors. For this I have a small code which runs above the bag file and just adds up the values in covariance matrix.

Please find the attached launch file and config file . Also, I am pasting few messages for IMU, GOS and odometry

IMU:

 header: 
   seq: 122
   stamp: 
     secs: 1531127130
     nsecs: 412077068
   frame_id: "imu_link"
  orientation: 
    x: 0.01904296875
    y: -0.0274047851562
    z: -0.852172851562
    w: 0.522216796875
  orientation_covariance: [24.0, 0.0, 0.0, 0.0, 24.0, 0.0, 0.0, 0.0, 24.0]
  angular_velocity: 
    x: 2.375
    y: -0.875
    z: 2.75
  angular_velocity_covariance: [24.0, 0.0, 0.0, 0.0, 24.0, 0.0, 0.0, 0.0, 24.0]
  linear_acceleration: 
    x: -0.270000010729
    y: 1.48000001907
    z: -1.27999997139
  linear_acceleration_covariance: [24.0, 0.0, 0.0, 0.0, 24.0, 0.0, 0.0, 0.0, 24.0]

GPS:

header: 
  seq: 8
  stamp: 
    secs: 1531127123
    nsecs:  87058067
  frame_id: "gps_link"
status: 
  status: 0
  service: 1
latitude: 50.72745
longitude: 7.087071
altitude: 110.3
position_covariance: [0.01, 0.0, 0.0, 0.0, 0.01, 0.0, 0.0, 0.0, 0.01]
position_covariance_type: 1

Odometry:

header: 
  seq: 633
  stamp:
    secs: 1531127147
    nsecs: 190536275
  frame_id: "odom"
child_frame_id: "base_link"
pose: 
  pose: 
    position: 
      x: 8.16897660416
      y: -7.75282666754
      z: 0.0
    orientation: 
      x: 0.0
      y: 0.0
      z: -0.6552952454
      w: 0.755372849231
  covariance: [0.375, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.375, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.375, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.375, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.375, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.375]
twist: 
  twist: 
    linear: 
      x: 0.866949711312
      y: 0.0
      z: 0.0
    angular: 
      x: 0.0
      y: 0.0
      z: 0.0533507514654
  covariance: [0.01, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.01, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.01, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.01, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.01, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.01]

Config file:

# https://github.com/cra-ros-pkg/robot_localization/blob/kinetic-devel/params/dual_ekf_navsat_example.yaml

ekf_se_odom:
    frequency: 30
    sensor_timeout: 0.1
    two_d_mode: true

    map_frame: map
    odom_frame: odom
    base_link_frame: base_link
    world_frame: odom

    odom0: odometry/cov
    odom0_config: [false, false, false,    #X,Y,Z
                 false, false, true,       #roll,pitch,yaw
                 true,  true,  false ...