Hello,
First of all, I am ultra newbie.
I am trying to build a robot which can go a spesific coordinate in 2 dimention. I bought an Arduino Uno, 2 Dc motor, a motor shield , an ultra sonic sensor.
Here is my question. Can i track my position ? Can i use step motors and count steps ? İf yes I can buy step motors. Can i do that witch Dc motors ? ( because i would need reductors i think to use step motors and price will be higher and it would be harder to build )
I think my question is not very clear. Because i am at very begining. I am waiting for your help. 
thank you and have a nice day.
Outdoors, with a clear view of the sky, GPS can simply and cheaply locate your robot, but not very accurately (within about 3 meters at the very best). But finding the position of a robot indoors is very difficult.
You can count wheel rotations using wheel or shaft encoders, but wheels slip.
Alternatives are expensive. They include external sensors like ceiling cameras or Pozyx.
it should be indoor. gps is not an option. sorry not to say that in post. encoders for servos i think and uno has 2 servo capacity which limits me. thank you for your help i am open to all kind of information if you want to add anything .
btw, can you say me the key words for this kind of projects. path finder, path planner is not what i want i think
During my school time, heading for my MS degree, I faced a a coarce called "Microcomputer technic". A terribly demanding exercise was to make a robot navigate using some, 3, IR transmitting light houses placed in the room. A rotating head on the robot checked the angles to the light houses and calculated its position. Only a few students managed to make it work. That was some 1976..
Look at garden grass cutting robots. They need to find the charging station. How? Spinn around and look for the IR beam from the power station....
thank you Mr.
It should go any position. I asked to my teacher to give me a homework to develop my coding skills and he gave me this. I thought it would be easy when i hear at first but now i cant manage to pick right hardware 
Your idea is pretty cool and useful but my project should be about calculating robot's position and going a given coordinate. that coordinate can be any coordinate.
Your teacher oviously has no knowledge about things like this. Present the answers given here to him and ask for information, help.....
Railroader:
Your teacher oviously has no knowledge about things like this. Present the answers given here to him and ask for information, help.....
do you mean that it is not possible to do it other ways or his way is not smart ?
Your teacher may not not know that indoor localization or positioning is a difficult problem.
Do some research on the topic and explain the difficulties to him.
On the other hand, maybe he does know and is hoping that you will figure that out.
Hi,
Welcome to the Forum.
Can you post exactly what your teacher set for you to do as a programming task.
Were you give the task written on a piece of paper or email?
Thanks.. Tom...