Accurate height detection can achieve positioning function in the room where GPS signal cannot cover. By adding a vertical specific position to the existing horizontal information, the first responder can determine the floor of the smartphone user triggering the emergency call. The typical relative accuracy of bmp390 is + / - 0.03 , which is superior to any other similar products on the market today, and the typical absolute accuracy can reach + / - 0.5 .Its excellent accuracy is due to the significant improvement in temperature stability, drift behavior and noise reduction. The of pressure sensor bmp390 can provide unparalleled accuracy for height tracking in smart phones and wearable and ear wearable devices. Thanks to the improved resolution, the new bmp390 can measure height changes below 10 cm, and the accuracy is 50% higher than that of the previous generation of sensors. Cjmcu-390 bmp390l digital atmospheric pressure sensor replaces for bmp388 bme280 The sensor operates at full operating temperature (0 ℃ to 65 ℃) The average temperature coefficient shift (TCO) is only + / - 0.6 PA / K. In addition, the noise is also very low, only 0.9 PA, which is 25% lower than the previous generation bmp380. The device also has high long-term stability and low short-term and long-term drift, Manufacturer: Akfldms