Introducing LoRa Cloud Geolocation 

LoRa Cloud Geolocation is a simple cloud API that can easily be integrated with a LoRaWAN® network server (or application server) to enable the estimated location of any LoRaWAN device. When gateways receive the data packet transmitted by LoRa®-based devices, they also generate metadata such as received signal-strength, signal-to-noise ratio and time of arrival. When this metadata from the gateways is assembled into a suitable query, and transmitted via an HTTP post request, then the service is able to calculate a location.

The service does not require any special hardware or software on the device itself, and there is no requirement for a GPS (or similar) chipset. Thus the service enables geolocation with no additional power consumption in the device. 

Requirements

  • LoRaWAN gateways that receive data packets from LoRaWAN devices
  • A network server that retains the received signal-strength and signal-to-noise ratio of all antennae on all gateways that receive the packets
  • The location (latitude, longitude and altitude) of every antenna on every gateway that receives a packet from the device to be located
  • An API key (token) to authenticate the user with each query
  • Optional: Accurate time of arrival time-stamps from each antenna on each gateway (requires specific gateway hardware e.g. Semtech gateway reference design V2.x)

Operation

When a LoRaWAN device transmits a packet, it can be received by any LoRaWAN gateway that is in range of that device. Sometimes the packet travels directly from the device to the gateway (the direct path or line of sight) whereas other times it reflects off buildings and other objects en route from the device to a gateway. Some gateways will receive the packet via more than one path which may be a combination of the direct path plus one or more reflected signals, or even just a combination of reflected signals.

In a LoRaWAN network, gateways forward the received packet to a network server. In the case where a single LoRaWAN packet is received by multiple gateways then the network server will retain one copy and delete all others. While this functions perfectly for recovering the payload of the packet, it does not serve the needs of LoRaWAN-based geolocation. In order to calculate a location, the metadata from each and every copy of the packet should be retained for use in the geolocation service. Where gateways have more than one antenna, then the received metadata for all the copies of the packet should be retained too.

 lost dog illustration-01
 Geolocation-picture1

Calculation of Location 

There are several algorithms available in the LoRa Cloud Geolocation service. The simplest of which requires the signal-strength and signal-to-noise ratio for each copy of the packet. If a single LoRaWAN packet from a device is received on multiple LoRaWAN gateways, then, for each receiving antenna, the signal-strength, signal-to-noise ratio, plus the antenna location (latitude, longitude and altitude) is compiled into a query and sent to the LoRa Cloud Geolocation service. The service will respond with the most likely location of the device based on the information contained in the query.

If multiple packets are received from the device in the same location, then there is the potential to process all the receptions together to get an improved location result.

Features

  • Simple API accepting signal-strength, signal-to-noise ratio and time of arrival data from LoRaWAN-based gateways and returning an estimated location
  • Supports all LoRaWAN-based gateways, with or without accurate time of arrival data
  • Compatible with all LoRaWAN-based devices on all LoRaWAN-based networks
  • Options for including multiple packets in a single query for improved accuracy
  • 100% stateless with all required data included in the query
  • No device identity required - total device anonymity 

Learn More

Contact loracloudservices@semtech.com to request more information.