RFI Solver Software for LoRa® Localisation

The RFI Solver Software is the centralized function to enable localisation of LoRa® sensors. With hardware limitations and the inherent energy constraints of LoRa® sensor network devices, GPS can not be used to pinpoint the location of the sensors. As an alternative, Time Difference of Arrival (TDoA) techniques for ranging (estimating the distance between two communicating nodes) have been widely proposed as a necessary ingredient in solutions for LoRa® sensor networks. In the RFI Solver Software the TDoA method of locating sensors has been implemented so that it calculates GPS coordinates from the timestamped message received from the gateways.

TDoA ranging requires that the message from a sensor is received simultaneously by multiple gateways in the LoRa® network. The time difference between the arrival of the message at each gateway is then used to calculate the location of the sensor. Timekeeping in the gateways, as well as very accurately timestamping of the received messages are essential to support the TDoA function.

 

LoRa_solver_diagram 

Solver Server Functions

One of the main functions of the RFI solver Server is to turn the received timestamps, received from the gateways, into GPS coordinates (latitude, longitude and altitude) for each sensor. Additionally the server stores all the timestamps for replay, or re-calculation at a later instance. Thereby making it possible to track a sensor traveling through the network. The server supports an API for storing and retrieving timestamps of the LoRa® messages as well as displaying the location of the sensors with the aid of Google maps, or on a local (leaflet) map.

 

To see a live demo of the Localisation function click here. On the map you see the geolocation of a LoRa sensor. The geolocation of the LoRa sensor is calculated from the time difference that the transmitted message from the sensor arrives at each LoRa base station. This method of geolocation is also known as Time Difference of Arrival (TDoA) localisation.

Solver_UI

 

Software Features

  • Calculate location (latitude, longitude, altitude) from timestamps (API) from received LoRa® messages
  • Store timestamps (250/s) and retrieve them (API)
  • OAuth 2.0 and user accounts
  • A client token can be used to only access certain sensors, applications or both
  • Fully redundant, clusterable
  • Google map support and leaflet support for local maps
  • Multi vendor and multi timestamp version (accuracy) support

Order code: RE.70.RSSx