摘要 |
A locator (100) receives signals from at least one beacon (110, 112 and 114). At least one beacon has a barometer (122, 124 and 126) for measuring local air pressure. The air pressure information is transmitted by the beacons with the position finding signals. The locator (100) uses the local air pressure information to calibrate its barometer (120). The barometer (120) may be used to measure the altitude of the locator (100). |