Detecting when a device moves towards another device.

Hi all,
im struggling to make this idea work.

I want to turn on some LED's when i move close to the device. But i dont want the LED's to come on when just anyone moves around the deivice so a motion sensor isnt going to work.
I need the range to be about 10 meters when it comes on. I want to make the deivce small and battery powered. Something like a RFID tag but much longer range.

The idea is to make the door handles on my project car light up as I approach similar to the soft entry system on BMW's newer cars.

The project is Arduino powered so the LED fading is done via that.

Would this be possible? Any ideas?
Thanks for any help.
Rob

I would suggest a search for long range RFID.

Im not sure how to go about using it. Are there any guides on it at all?
Ive seen the user of shorter range ones, but never long range ones.

How do BMW and other car manufactures do it? a repeated ping on a certain freq maybe is that possible?