"SmartPush" is the online advertising platform for an area marketing.
It can detect user devices in real-time then send push notification with the incentive items like a coupon and variable information.
This platform supports several approach to get location information not only GPS but also Wi-Fi and Bluetooth Low Energy(BLE).

Just put a Sensor on your shop.
Logs of visitor's movements are saved and can be analyzed.
Adjusted visitors who are far from and close to the shop.

(as of May, 2014)

Sensor Price Range Smartphone App. Sensing Accuracy
BLE Beacon Competitive Required 4 inch to 30 feet
Wi-Fi sensor Good No need 30 feet to 100 feet
Wi-Fi router Good No need 30 feet to 100 feet
GPS Competitive Required 100 feet to 300 feet

BLE Beacon Wi-Fi sensor