In the context of aviation and aerospace, the "Accumulated Delta range" refers to the total variation or change in the range of an aircraft or spacecraft's navigation system over a specified period. This can be due to various factors, including navigation system errors, GPS signal degradation, or atmospheric interference.

Delta range, also known as "delta-r" or "Δr", represents the difference between the actual range and the predicted or nominal range of an aircraft or spacecraft from a reference point, such as a ground station or a navigation aid. The accumulated delta range is the cumulative sum of these delta-r values over time.

In other words, the accumulated delta range represents the total error or uncertainty in the range measurement, which can affect the accuracy of navigation, guidance, and control systems. This value is often used to assess the performance of navigation systems, such as GPS, and to estimate the uncertainty in an aircraft's or spacecraft's position and velocity.

For example, if an aircraft's navigation system has an accumulated delta range of 100 meters over a period of 10 minutes, it means that the aircraft's actual range from a reference point has varied by a total of 100 meters over that time period due to various errors and uncertainties in the navigation system.

The accumulated delta range is an important parameter in aviation and aerospace, as it affects the overall accuracy and reliability of navigation systems, which are critical for safe and efficient flight operations.