LaunchDetector Class Reference

Sliding-window launch detector based on acceleration magnitude. More...

#include <LaunchDetector.h>

Collaboration diagram for LaunchDetector:

Public Member Functions
	LaunchDetector (float accelerationThreshold_ms2, uint16_t windowSize_ms, uint16_t windowInterval_ms)
int	update (AccelerationTriplet accel)
bool	isLaunched ()
uint32_t	getLaunchedTime ()
float	getMedianAccelerationSquared ()
void	reset ()
CircularArray< DataPoint, kCircularArrayAllocatedSlots > *	getWindowPtr ()
float	getThreshold ()
uint16_t	getWindowInterval ()
uint16_t	getAcceptableTimeDifference ()

Detailed Description

Sliding-window launch detector based on acceleration magnitude.

Predicts launch by looking for a sustained acceleration above a threshold It takes the median acceleration magnitude over a window of time and compares it to the threshold. Because of the size of the window, short spikes are ignored.

The window is a circular array / rolling window of acceleration magnitudes squared

The delay in launch detection will equal half the window size because the median will only be high once half the window is high

Note

When to use: detect liftoff robustly against spikes by requiring a sustained acceleration median over a configurable window.

Definition at line 51 of file LaunchDetector.h.

Constructor & Destructor Documentation

LaunchDetector()

LaunchDetector::LaunchDetector	(	float	accelerationThreshold_ms2,
		uint16_t	windowSize_ms,
		uint16_t	windowInterval_ms )

Constructor

Parameters

accelerationThreshold_ms2	The threshold for acceleration to be considered a launch
windowSize_ms	The size of the window to calculate the median acceleration. The delay in launch detection will equal half the window size A window too small will cause false positives.
windowInterval_ms	The interval between acceleration value in the window You must be able to update the detector faster than this interval The detector will reject data that comes in faster than this interval to maintain this interval or slower

Definition at line 24 of file LaunchDetector.cpp.

Member Function Documentation

getAcceptableTimeDifference()

uint16_t LaunchDetector::getAcceptableTimeDifference ( )

inline

Definition at line 88 of file LaunchDetector.h.

getLaunchedTime()

uint32_t LaunchDetector::getLaunchedTime ( )

inline

Definition at line 75 of file LaunchDetector.h.

getMedianAccelerationSquared()

float LaunchDetector::getMedianAccelerationSquared ( )

inline

Definition at line 76 of file LaunchDetector.h.

getThreshold()

float LaunchDetector::getThreshold ( )

inline

Definition at line 85 of file LaunchDetector.h.

getWindowInterval()

uint16_t LaunchDetector::getWindowInterval ( )

inline

Definition at line 87 of file LaunchDetector.h.

getWindowPtr()

CircularArray< DataPoint, kCircularArrayAllocatedSlots > * LaunchDetector::getWindowPtr ( )

inline

Definition at line 83 of file LaunchDetector.h.

isLaunched()

bool LaunchDetector::isLaunched ( )

inline

Definition at line 74 of file LaunchDetector.h.

reset()

void LaunchDetector::reset

(

)

Definition at line 192 of file LaunchDetector.cpp.

update()

int LaunchDetector::update

(

AccelerationTriplet

accel

)

Updates the detector with new acceleration data

Parameters

accel

The newest acceleration data (triplet of x, y, and z acceleration data points)

Returns

: False if the data is ignored, true if the data is accepted

Definition at line 44 of file LaunchDetector.cpp.

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The documentation for this class was generated from the following files:

• LaunchDetector.h
• LaunchDetector.cpp