# Best/simplest way to implement TF for localization application.

Hello everyone! I'm still a beginner user of ROS, so I apologize in advance if this is too much of a simple question.

I'm working with a simple mobile robot powered by ROS for a localization application. Basically, I have two sensors: one that gives the 2D position **L'** of a known landmark on the **robot's reference frame**, and another one that gives the **robot's heading on the world frame**.

The goal is to calculate the robot's real position **X** on the **world frame** using: **L**, the known landmark's position on the world frame, **L'**, the landmark's position on the robot's frame as given by the first sensor, and **phi**, the robot's heading given by the second sensor.

I already do this by making use of rotation matrices, but since this code might be used by other students after me, I want to know if there's a simple way to implement this coordinate change calculations with TF, since I have never used TF before.

Thanks a lot in advance!

PS.: I'm using ROS Melodic Morenia and programming on Python.

Probably, and it shouldn't even be very hard, so I encourage you to try it using the tutorials, but I am not sure what exactly you mean by "this".

Hey! Sorry, I edited my post. I want to know how to implement this coordinate change calculations. I mean, I have the robot's heading and the landmarks positions according to the robot's frame and the world frame. So I need to use this to find the coordinates of the robot on the world frame.