rocket apogee with kalman filter

Projects General Guidance
1

i'm working on a rocket project. i almost finished it's body, nosecone, avionics etc.

but i'm not sure how to detect apogee with accelerometer and bmp180 pressure sensor?

while i was researching about this problem, i came cross this pdf link:

http://home.earthlink.net/~david.schultz/rnd/2004/KalmanApogeeII.pdf

but link was broke. does anyone have this pdf?

or any idea for make an algorithm to detect apogee with bmp180 pressure sensor?

2

http://home.earthlink.net/~david.schultz/rnd/2004/KalmanApogeeII.pdf attached.

KalmanApogeeII.pdf (629 KB)

3

thank you @jremington :slight_smile:

4

gryhkn:
but i'm not sure how to detect apogee with accelerometer and bmp180 pressure sensor?

Isn't it as simple as the altitude when the acceleration magnitude is at its minimum (freefall)? The magnitude is the sqrt() of the sum of the squares of the three accelerometer axes. You don't even need to do the sqrt() since all you want is a relative magnitude. Keep taking accelerometer readings and if the current sum of the squares is lower than previous low, record the altitude.

5

Isn't it as simple as the altitude

No. Take a look at the document I posted. A lot of careful thought and work went into it. For the curious I've attached David Schultz' precursor report, which delves more into the problems encountered.

KalmanApogee.pdf (235 KB)