I have been looking to analysis some flight data from two different on board sensors. I have two different altitude data. One is from a pressure sensor and another is from GPS. Both the data reference are same, above mean sea level. I was looking for method to test how much they agree each other. Noted that, as they are flight data, repetitive measurement is not possible, they are time series data and in some phase, altitude may increase (while ascending), decrease (while descending) and constant (level flight/taxiing). I would like to know, how much interchangeable they two sensors are. I am not clear if your method can be applied to this type of data. It would be great if you shed some light. Thanks