I need to develop a solution for determining whether an object/tag exists within a defined perimeter. The perimeter would be located indoors so GPS isn't an option. It would be an approx 10 metres x 10 metres rectangle. The 'tag' needs to fit in a person's pocket (however it could be battery powered), and I would need to know:

1. when the tag leaves the perimeter (doesn't have to be exact and I don't care where it is located within the perimeter)
2. the identify of the tag that left the perimeter (as there will be 10-20 objects in the perimeter that need to be tracked)

Would an active RFID system be the way forward? I'm thinking that I'd need 3-4 receivers spaced around the perimeter so that I can combine the readings from them to estimate the position.

Really appreciate any advice or suggestions.

I need to develop a solution for determining whether an object/tag exists within a defined perimeter. The perimeter would be located indoors so GPS isn't an option. It would be an approx 10 metres x 10 metres rectangle. The 'tag' needs to fit in a person's pocket (however it could be battery powered), and I would need to know:

1. When the tag leaves the perimeter (doesn't have to be exact and I don't care where it is located within the perimeter)
2. Identify the tag left the perimeter (as there will be 10-20 objects in the perimeter that need to be tracked)

Would an active RFID system be the way forward? I'm thinking that I'd need 3-4 receivers spaced around the perimeter so that I can combine the readings from them to estimate the position.

Really appreciate any advice or suggestions.