@@ -10,13 +10,12 @@ _On this picture we can see that the quartz clocks drift much faster than the GN
...
@@ -10,13 +10,12 @@ _On this picture we can see that the quartz clocks drift much faster than the GN
**There are three main regions that can be identified in an Allan deviation plot:**
**There are three main regions that can be identified in an Allan deviation plot:**
**- Short-term stability:** This region corresponds to averaging times of less than 1 second. In this region, the Allan deviation is dominated by random noise and is inversely proportional to the square root of the averaging time.
***Short-term stability:** This region corresponds to averaging times of less than 1 second. In this region, the Allan deviation is dominated by random noise and is inversely proportional to the square root of the averaging time.
***Medium-term stability:** This region corresponds to averaging times between 1 second and 1 day. In this region, the Allan deviation is dominated by the stability of the oscillator or clock.
**- Medium-term stability:** This region corresponds to averaging times between 1 second and 1 day. In this region, the Allan deviation is dominated by the stability of the oscillator or clock.
***Long-term stability:** This region corresponds to averaging times greater than 1 day. In this region, the Allan deviation is dominated by other factors such as aging, temperature effects, and environmental disturbances.
**- Long-term stability:** This region corresponds to averaging times greater than 1 day. In this region, the Allan deviation is dominated by other factors such as aging, temperature effects, and environmental disturbances.
Allan variance is useful for measuring the stability and accuracy of a time and frequency signal over different time scales. It allows for the identification of different sources of error and instability, such as short-term noise, medium-term oscillator stability, and long-term environmental effects. Additionally, Allan variance can be used to compare the performance of different oscillators or clocks, and to determine the optimal averaging time for a specific application.
Allan variance is useful for measuring the stability and accuracy of a time and frequency signal over different time scales. It allows for the identification of different sources of error and instability, such as short-term noise, medium-term oscillator stability, and long-term environmental effects. Additionally, Allan variance can be used to compare the performance of different oscillators or clocks, and to determine the optimal averaging time for a specific application.
#### Sources :
#### Sources :
- Calero, D., & Fernandez, E., & Parés, E. (2016) Positioning performance of Chip-Scale Atomic Clock GNSS augmentation systems. [https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=7849326](https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=7849326)
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- Calero, D., & Fernandez, E., & Parés, E. (2016) Positioning performance of Chip-Scale Atomic Clock GNSS augmentation systems. https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=7849326
