how can i program the internal accelorometer to get the distance

[EKang.1]

Am using STM32F407VG -TX/DISC1

[TDK]

To get what distance?

You can't convert acceleration to distance in general. The noise and offset ruin the calculation.

[EKang.1]

so how do you approach this issue. Am developing a sytem that uses the 3-axis acceleration then convert them to distance since the system is suppose to be mounted on my leg then simulate the distance i have travel in real time

[TDK]

This is a common desire. There is a lot on information online for "how to measure distance with an accelerometer". Here are a few results:

https://stackoverflow.com/questions/17572769/calculating-distances-using-accelerometer

https://www.researchgate.net/post/Calculating_Speed_and_Distance_from_a_3-axis_accelerometer

The longer answer is that it's complicated and companies use a lot of tricks to estimate distance traveled based on acceleration. However, they are just that--estimates--and not measurements. For example, your iPhone can reasonably accurately measure how many steps you take from measuring oscillations in the acceleration over time, but it needs to estimate your stride length to get total distance.

There are incredibly precise IMU units which can do this, but the cost and weight of those is prohibitive for most applications.

[S.Ma]

Sensor fusion is to combine multipkr sensors to estimate relative movements. Estimating delta coordinates is as I recall dead reckoning.