Someone asked us today why LoRaWAN can’t do GPS. As I’ve written previously, when it comes to battery powered LoRa endpoints you don’t encounter many LoRaWAN-based solutions that also offer GPS. If they do, battery life is measured in days. This comes down to a few simple reasons:
1. LoRaWAN gateways can’t broadcast to battery powered LoRaWAN endpoints.
2. LoRaWAN has limitations on the amount of upstream and downstream data sent per day, per endpoint.
3. Given 1 and 2, it’s not feasible to keep endpoints updated with assisted GPS data on a LoRaWAN network, just with throughput constraints and given that assisted GPS data must be frequently refreshed.
4. As written previously, LoRaWAN doesn’t work in a straightforward way for mobile endpoints. Mobile endpoints using LoRaWAN, for example, should increase spreading factor if not acknowledged. (They can’t since there is no acknowledgement.) Most of the network area thus becomes inaccessible to bulk data transfer.
Haystack hardware uses a LoRa radio but not LoRaWAN. Haystack has broadcast and multicast networking abilities, plus timeslotting abilities for efficient channel multiaccess. LoRaWAN has none of these. Haystack also developed an encoding technology that improves the reliability of data transfers by 25–100x over LoRaWAN (14–20dB). And Haystack supports conventional GPS-related features like real-time, low power geofencing.