Find coordinate system in LLA (latitude/longitude/altitude)

edit

Hello everyone,

I have an IMU that outputs the GPS location of my robot in LLA format (latitude/longitude/altitude).

Assue I have my robot in location x according to GPS. I know there is an object near the robot by using LiDAR. Now I want to obtain the location of the object in GPS. However, by just using one GPS location of the robot I can not find the location of the object in the GPS coordinate system because I do not have the direction of the robot in the GPS coordinate system.

By knowing several GPS measurements during robot movement, How can I find the robot's direction in the GPS coordinate system?