ekf2 wind: use noise spectral density for process noise tuning

The noise spectral density, NSD, (square root of power spectral density) is a
continuous-time parameter that makes the tuning independent from the EKF
prediction rate.
NSD corresponds to the rate at which the state uncertainty increases
when no measurements are fused into the filter.
Given that the current prediction rate of EKF2 is 100Hz, the
same tuning is obtained by dividing the std_dev legacy parameter by 10:
nsd = sqrt(std_dev^2 / 100Hz)
This commit is contained in:
bresch
2022-06-14 18:39:10 +10:00
committed by Paul Riseborough
parent e105869986
commit 0d256b8ff6
5 changed files with 14 additions and 12 deletions
+5 -3
View File
@@ -320,15 +320,17 @@ PARAM_DEFINE_FLOAT(EKF2_MAG_B_NOISE, 1.0e-4f);
PARAM_DEFINE_FLOAT(EKF2_MAG_E_NOISE, 1.0e-3f);
/**
* Process noise for wind velocity prediction.
* Process noise spectral density for wind velocity prediction.
*
* When unaided, the wind estimate uncertainty (1-sigma, in m/s) increases by this amount every second.
*
* @group EKF2
* @min 0.0
* @max 1.0
* @unit m/s^2
* @unit m/s^2/sqrt(Hz)
* @decimal 3
*/
PARAM_DEFINE_FLOAT(EKF2_WIND_NOISE, 1.0e-1f);
PARAM_DEFINE_FLOAT(EKF2_WIND_NSD, 1.0e-2f);
/**
* Measurement noise for gps horizontal velocity.