||With the rise of the Internet of Things, many low power wide area networks have gradually developed.On the other hand, many IoT applications require geolocation information.Geolocation information can be obtained from GPS, but GPS is not suitable for use in sheltered environments, so other positioning techniques need to be developed.In general, there are two main challenges in positioning problems: the first is signal multipath and insufficient number of gateways.multipath transmission usually occurs when there is an obstacle between the devices, causing a serious time delay;the second is that the number of gateways received is insufficient. due to the high price of gateway and the high cost of deployment, the number of gateways is usually sparse in deployment.TDOA requires at least three gateways for positioning.The more the gateway, the more higher the accuracy of positioning. We used the Raspberry Pi and LoRa chips to implement low-cost LoRa gateways and positioning methods on LoRaWAN.Through the method we proposed, no additional wiring is required when adding the gateway, so it is suitable for indoor, edge or sheltered scenes where the signal can not reach.We have set up 3 general gateways and 3 lightweight gateways that we made in the campus.Our proposed method has an average positioning errors of up to 99 meters under different SF measurements. In the same situation, the average positioning errors measured by using only three general gateways for positioning is 203 meters.|
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