From dabba69b5ef8d2854146ca293f66ab4b288da9a6 Mon Sep 17 00:00:00 2001 From: Peter Barker Date: Tue, 7 Sep 2021 17:01:18 +1000 Subject: [PATCH] AP_NavEKF3: improve description of XKF4/NKF4 fields Courtesy Paul Riseborough here: https://github.com/ArduPilot/ardupilot_wiki/issues/3641#issuecomment-913577132 --- libraries/AP_NavEKF3/LogStructure.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libraries/AP_NavEKF3/LogStructure.h b/libraries/AP_NavEKF3/LogStructure.h index 0a0ceb9016..702c066682 100644 --- a/libraries/AP_NavEKF3/LogStructure.h +++ b/libraries/AP_NavEKF3/LogStructure.h @@ -173,7 +173,7 @@ struct PACKED log_XKF3 { // @LoggerMessage: XKF4 -// @Description: EKF3 variances +// @Description: EKF3 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 EK3_MAG_I_GATE, EK3_HGT_I_GATE, etc // @Field: TimeUS: Time since system startup // @Field: C: EKF3 core this data is for // @Field: SV: Square root of the velocity variance