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LoRaWAN ™ and LoRa Alliance ™ are marks used under license from the LoRa Alliance ™ www.lora-alliance.org GEOLOCATION WHITEPAPER GEOLOCATION TECHNOLOGY COMPARISON The graphic above provides a visual comparison of cost vs. accuracy vs. battery life of several geolocation technologies. As represented in Figure 3-1, the LoRaWAN™ protocol provides two methods for geolocation determination: Received Signal Strength Indication (RSSI) based, for coarse positioning, or Time Difference Of Arrival (TDOA), for finer accuracy. This paper will discuss TDOA, which is particularly well suited for applications requiring low-cost, battery- powered end-devices with positioning accuracies in the 20m to 200m range. Rural deployments with clear line of sight and recommended gateway-deployment geometry will achieve accuracies near the lower end of the scale. Multipath issues inherent in urban and dense urban environments will provide accuracies toward the higher end of the scale. In general, accuracy improves as operators densify their gateway networks. Best power efficiency is achieved for end-devices requiring infrequent location determination (days or weeks). These end-devices are typically stationary or infrequently moving assets implemented as Class A. The geolocation capability for these end-devices comes at no additional bill of materials (BOM) cost. Mobile assets requiring more frequent position determination will transmit more frames, consume more power, increase end-device costs (e.g., batteries) and will often need to be implemented as Class B or Class C end-devices. Usage of a higher data rate (say SF7) will help bound the increased power needs. The focus of this paper is outdoor, wide-area geolocation. It should be noted, however, that the LoRaWAN community is investigating various techniques to provide indoor accuracies of 10m or better (100m gateway density, improved clock sources, etc.). This would compete favorably with indoor WiFi Angle of Arrival (AOA) techniques providing 1m to 3m accuracies. Figure 3-1: Comparison of Geolocation Technologies LoRaWAN TDOA/RSSI • Lowest cost solution. Works natively with any LoRaWAN sensor • LoRaWAN enables long battery life use cases • TDOA: 20-200m accuracy range depending on conditions • RSSI: 1000-2000m accuracy WiFi Location • Cost efficient solution for outdoor and indoor solution • Accuracy increases with hotspot density BLE Requires a BLE beaconing system Indoor solution GPS/AGPS • 1 GPS adds $5-$10 to the BOM • Most accurate but power consuming solution • AGPS brings battery consumption improvement 3 LoRaWAN TM RSSI 1000-2000m LoRaWAN TM TDoA 20-200m