Finding position of an object

Hi All,
Suppose I would like to know how far I am from a reference point and in what direction I lay with respect to the reference point, what would I use? I thought about using something that would transmit its location, as a reference point, something like a beacon. The only problem with that is it does not give you information on how far it is from you. It may tell me in what direction it lies with respect to me, but I have no way of knowing how far away it is. I thought about using GPS but as everyone knows, GPS can be off by several meters. Please leave your comments or suggestions, and thanks in advance for your time.

The questions is just too vague to even attempt to answer.

The problem will be very different if you are looking at two people that are driving around a city, or two players on a football field, or two marbles on a table.

What are the objects? How big are they? How far apart can they be? How accurately do you need to measure the relative distance? How accurately do you need to measure the direction? Do you need a relative direction or an absolute direction?

---55p