Barometric Pressure Unit is a barometer unit, which integrates the Bosch BMP280 pressure sensor to measure atmospheric pressure and estimate the altitude. The relative accuracy can reach ± 0.12hpa, equivalent to ± 1m height difference. At the same time, the temperature drift coefficient is very low, which can reach 1.5 PA / K, that is, the temperature drift is 12.6 cm / K. in addition, there is an integrated temperature sensor in the chip.