Can you attach a gps chip to your cell phone?

[AlexandraN]

Are there any physicall chips that you can attach to a cell phone and then live of their battery and antenna and send tha location of the cell phone to an account or something that you can access. (like those gps anti theft devices for cars and bikes but just a chip for your cell phone that isn't gps enabled). If there is where can you buy them from?