Indoor Positioning Technologies and Techniques

Current technologies include GPS, IR, ultra-sound, RFID, Bluetooth, UWB, magnetic technology, and WiFi. GPS is the most widely-used technology for location and positioning, but is very inaccurate in indoor environments due to signal loss Zhai 2015.
Information provided by one or more wireless sensing technologies is used to locate and provide location information. Techniques include triangulation, fingerprinting, proximity, and vision analysis Deepesh 2016.
  1. Triangulation requires three known reference elements with pre-determined coordinates. Based on received signal strength (RSS), angle of arrival (AOA), and time of arrival (TOA), an accurate location can be determined. Most current solutions are based on RSS Yan 2015.
  2. Fingerprinting involves pre-measured location related data and includes two phases: an offline training phase, where data is collected, analyzed and stored, and an online position determination phase, where location is determined by comparing real-time data with the data collected during the training phase. WiFi fingerprinting is the most common technique currently used for indoor positioning.
  3. Proximity location is less accurate, but useful in many applications, such as determining if a device is in a particular room. If a device is sensed to be within a certain distance of a detector, then proximity can be determined.
  4. Vision analysis uses real-time captured images to determine the location of a pre-defined object. Images from multiple networked cameras are usually analyzed and compared to calculate the current location of the tracked object.