Locating nearest device position

I have the following use case:

Given a set of points in a space, I would like to use a smartphone to detect and locate the closest point (Possibly accurate to the at least a meter range)

I am not familiar with this field myself, so I would like to know if you have some input on how to get started with the research.

• What would be the best technology to use? Bluetooth, GPS, NFC
• What's the cheapest option to use for the devices? And what would be the overall best option regardless of price?

if you read this : https://en.wikipedia.org/wiki/Near-field_communication

you can see check this :

Technology       NFC                 Bluetooth       Bluetooth Low Energy
Range           < 20 cm           ≈100 m (class 1)          ≈50 m


first you will find out that the NFC ins,t your choice because it,s short Range and, the range of Bluetooth ins,t enough the only choice from the given options is GPS but you have two main issue using GPS to locate other devices.

• the environment terrain highly affects on position locating when you are using GPS. environment terrain like when you are in mountainous area or when you are in the location of a city that surrounded by skyscrapers or tall buildings and .....

• in GPS modules you have no access to the other GPS modules and instruments who aren't belong to you but, if the other devices that you are going to access their location are yours, it's easy, you can send the devices locations together and find their relative location & directions