隨著物聯網的興起，許多低功率廣域網路逐漸被發展起來。另一 方面，許多物聯網應用需要地理資訊。地理資訊雖可透過 GPS 取得， 但 GPS 不適用於有遮蔽物的環境下，因此需要發展其他的定位技術。 一般而言，定位問題的挑戰主要有二：訊號多路徑與閘道器數量不 足。當通訊裝置之間有障礙物通常會導致多路徑傳輸，造成嚴重的 時間延遲。第二是定位接收的閘道器數量不足，由於閘道器的高價格 以及高佈署成本，閘道器的數量通常佈署稀疏。以 TDOA 定位技術 來說至少需要三個接收閘道器。越多閘道器定位精準度愈高。我們在 LoRaWAN 上透過樹莓派和 LoRa 晶片實作低佈署成本的 LoRa 閘道器 以及定位方法。透過我們所提出的方法使得增加閘道器時不需要額外 的佈線，因此很適合放在訊號到達不了的室內、邊緣或是遮蔽的場景 之中。我們在校園內佈署了 3 個一般的閘道器以及 3 個我們製作的輕 量型閘道器，我們所提出的定位方法在不同 SF 的測量下平均定位誤差 最多 99 公尺，而在相同的情況下只使用 3 個一般閘道器來做定位所測 量的平均定位誤差達到 203 公尺。;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.
