#### Topic: Ecodriving g force threshold calculations

I understand that Wialon  uses dv/dt(+0.7)/3.6/9.8 to define g force threshold for acceleration and deceleration, in Eco Driving Settings to analyse driving behaviour.

Accordingly violations when are generated corresponding acceleration g value is shown in the table .

Based on above , as per Wialon speed differential of 11 kmphs will imply about 0.18 g

Whereas speed increment of 11 kmphs actually means 0.31 g

I am not sure why this +0.7 time correction is being applied , as standard mathematical practice to calculate g is dv/dt/3.6/9.8.

I have tried to get an answer from Wialon experts , but no success.

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Cheers

#### Re: Ecodriving g force threshold calculations

Hello Rajeev Gabbar,

You are absolutely correct in describing the formula that Wialon uses to calculate acceleration.
At the moment, the discreteness in Wialon is one second. There are situations when messages come with a difference per second (although in fact, we are talking about milliseconds), therefore, in order to neutralize such situations and calculate the acceleration values, it was decided to make an adjustment. Empirically, a value of 0.7 was chosen. That this correction exists in order to make the algorithm more consistent with real data (it is important to note that in this way we do not increase the acceleration).

The algorithm has been working for more than 7 years and during this time did not raise a question. Our algorithm primarily aimed at fixing the fact of violation and setting penalty points.

The question will be solved automatically when we add the ability to work with milliseconds in Wialon (then we will have the exact time and we will not need any correction values).
If it is essential for you to obtain accurate numerical values of acceleration, then you should choose terminals with internal algorithms for calculating this value, not GPS.

Nastassia Maslovskaya

#### Re: Ecodriving g force threshold calculations

Nastassia,

I am in absolute agreement and also agree that applied algorithm with .7 time correction is working perfectly fine.

All I am saying is that since it is an algorithm adjusted value , hence it cannot and should not be stated as g value !

In the user interface it can be shown as wg , instead of g .

Currently g , as shown is being confused with general mathematical formula of calculating acceleration as g.

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Cheers