US Patent 7324002 Outdoor computer

A method for implementing a weather alarm in an outdoor computer includes defining atmospheric-pressure data repeatedly, defining altitude data repeatedly and essentially simultaneously with the atmospheric-pressure data, with the aid of a satellite positioning system, and converting both measured variables into the same measurement unit, either pressure or altitude. The difference between the converted variables is determined and is stored as a reference value, the difference between the converted variables is repeatedly monitored, and when the difference changes by more than a preset limit-value relative to the reference value, a weather alarm is given. Also an apparatus for performing the method.