From a62cb648673d493692f86be858d5bb72d8ae1565 Mon Sep 17 00:00:00 2001 From: Peter Barker Date: Tue, 7 Sep 2021 17:01:17 +1000 Subject: [PATCH] AP_NavEKF2: improve description of XKF4/NKF4 fields Courtesy Paul Riseborough here: https://github.com/ArduPilot/ardupilot_wiki/issues/3641#issuecomment-913577132 --- libraries/AP_NavEKF2/LogStructure.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libraries/AP_NavEKF2/LogStructure.h b/libraries/AP_NavEKF2/LogStructure.h index 460ac13c61..62abbd042c 100644 --- a/libraries/AP_NavEKF2/LogStructure.h +++ b/libraries/AP_NavEKF2/LogStructure.h @@ -166,7 +166,7 @@ struct PACKED log_NKF3 { // @LoggerMessage: NKF4 -// @Description: EKF2 variances +// @Description: EKF2 variances SV, SP, SH and SM are probably best described as 'Squared Innovation Test Ratios' where values <1 tells us the measurement was accepted and >1 tells us it was rejected. They represent the square of the (innovation / maximum allowed innovation) where the innovation is the difference between predicted and measured value and the maximum allowed innovation is determined from the uncertainty of the measurement, uncertainty of the prediction and scaled using the number of standard deviations set by the innovation gate parameter for that measurement, eg EK2_MAG_I_GATE, EK2_HGT_I_GATE, etc // @Field: TimeUS: Time since system startup // @Field: C: EKF2 core this data is for // @Field: SV: Square root of the velocity variance