From 9886b11f9910b53479e0fe21599c329c2aeb90b0 Mon Sep 17 00:00:00 2001
From: Hamish Willee <hamishwillee@gmail.com>
Date: Thu, 30 Jan 2020 11:29:42 +1100
Subject: [PATCH] EKF params - clarify body frame origin/orientation

---
 src/modules/ekf2/ekf2_params.c | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/src/modules/ekf2/ekf2_params.c b/src/modules/ekf2/ekf2_params.c
index 24782e5342..7d938b895a 100644
--- a/src/modules/ekf2/ekf2_params.c
+++ b/src/modules/ekf2/ekf2_params.c
@@ -819,7 +819,7 @@ PARAM_DEFINE_FLOAT(EKF2_TERR_GRAD, 0.5f);
 PARAM_DEFINE_INT32(EKF2_IMU_ID, 0);
 
 /**
- * X position of IMU in body frame
+ * X position of IMU in body frame (forward axis with origin relative to vehicle centre of gravity)
  *
  * @group EKF2
  * @unit m
@@ -828,7 +828,7 @@ PARAM_DEFINE_INT32(EKF2_IMU_ID, 0);
 PARAM_DEFINE_FLOAT(EKF2_IMU_POS_X, 0.0f);
 
 /**
- * Y position of IMU in body frame
+ * Y position of IMU in body frame (right axis with origin relative to vehicle centre of gravity)
  *
  * @group EKF2
  * @unit m
@@ -837,7 +837,7 @@ PARAM_DEFINE_FLOAT(EKF2_IMU_POS_X, 0.0f);
 PARAM_DEFINE_FLOAT(EKF2_IMU_POS_Y, 0.0f);
 
 /**
- * Z position of IMU in body frame
+ * Z position of IMU in body frame (down axis with origin relative to vehicle centre of gravity)
  *
  * @group EKF2
  * @unit m
@@ -846,7 +846,7 @@ PARAM_DEFINE_FLOAT(EKF2_IMU_POS_Y, 0.0f);
 PARAM_DEFINE_FLOAT(EKF2_IMU_POS_Z, 0.0f);
 
 /**
- * X position of GPS antenna in body frame
+ * X position of GPS antenna in body frame (forward axis with origin relative to vehicle centre of gravity)
  *
  * @group EKF2
  * @unit m
@@ -855,7 +855,7 @@ PARAM_DEFINE_FLOAT(EKF2_IMU_POS_Z, 0.0f);
 PARAM_DEFINE_FLOAT(EKF2_GPS_POS_X, 0.0f);
 
 /**
- * Y position of GPS antenna in body frame
+ * Y position of GPS antenna in body frame (right axis with origin relative to vehicle centre of gravity)
  *
  * @group EKF2
  * @unit m
@@ -864,7 +864,7 @@ PARAM_DEFINE_FLOAT(EKF2_GPS_POS_X, 0.0f);
 PARAM_DEFINE_FLOAT(EKF2_GPS_POS_Y, 0.0f);
 
 /**
- * Z position of GPS antenna in body frame
+ * Z position of GPS antenna in body frame (down axis with origin relative to vehicle centre of gravity)
  *
  * @group EKF2
  * @unit m
@@ -873,7 +873,7 @@ PARAM_DEFINE_FLOAT(EKF2_GPS_POS_Y, 0.0f);
 PARAM_DEFINE_FLOAT(EKF2_GPS_POS_Z, 0.0f);
 
 /**
- * X position of range finder origin in body frame
+ * X position of range finder origin in body frame (forward axis with origin relative to vehicle centre of gravity)
  *
  * @group EKF2
  * @unit m
@@ -882,7 +882,7 @@ PARAM_DEFINE_FLOAT(EKF2_GPS_POS_Z, 0.0f);
 PARAM_DEFINE_FLOAT(EKF2_RNG_POS_X, 0.0f);
 
 /**
- * Y position of range finder origin in body frame
+ * Y position of range finder origin in body frame (right axis with origin relative to vehicle centre of gravity)
  *
  * @group EKF2
  * @unit m
@@ -891,7 +891,7 @@ PARAM_DEFINE_FLOAT(EKF2_RNG_POS_X, 0.0f);
 PARAM_DEFINE_FLOAT(EKF2_RNG_POS_Y, 0.0f);
 
 /**
- * Z position of range finder origin in body frame
+ * Z position of range finder origin in body frame (down axis with origin relative to vehicle centre of gravity)
  *
  * @group EKF2
  * @unit m
@@ -900,7 +900,7 @@ PARAM_DEFINE_FLOAT(EKF2_RNG_POS_Y, 0.0f);
 PARAM_DEFINE_FLOAT(EKF2_RNG_POS_Z, 0.0f);
 
 /**
- * X position of optical flow focal point in body frame
+ * X position of optical flow focal point in body frame (forward axis with origin relative to vehicle centre of gravity)
  *
  * @group EKF2
  * @unit m
@@ -909,7 +909,7 @@ PARAM_DEFINE_FLOAT(EKF2_RNG_POS_Z, 0.0f);
 PARAM_DEFINE_FLOAT(EKF2_OF_POS_X, 0.0f);
 
 /**
- * Y position of optical flow focal point in body frame
+ * Y position of optical flow focal point in body frame (right axis with origin relative to vehicle centre of gravity)
  *
  * @group EKF2
  * @unit m
@@ -918,7 +918,7 @@ PARAM_DEFINE_FLOAT(EKF2_OF_POS_X, 0.0f);
 PARAM_DEFINE_FLOAT(EKF2_OF_POS_Y, 0.0f);
 
 /**
- * Z position of optical flow focal point in body frame
+ * Z position of optical flow focal point in body frame (down axis with origin relative to vehicle centre of gravity)
  *
  * @group EKF2
  * @unit m
@@ -927,7 +927,7 @@ PARAM_DEFINE_FLOAT(EKF2_OF_POS_Y, 0.0f);
 PARAM_DEFINE_FLOAT(EKF2_OF_POS_Z, 0.0f);
 
 /**
-* X position of VI sensor focal point in body frame
+* X position of VI sensor focal point in body frame (forward axis with origin relative to vehicle centre of gravity)
  *
  * @group EKF2
  * @unit m
@@ -936,7 +936,7 @@ PARAM_DEFINE_FLOAT(EKF2_OF_POS_Z, 0.0f);
 PARAM_DEFINE_FLOAT(EKF2_EV_POS_X, 0.0f);
 
 /**
- * Y position of VI sensor focal point in body frame
+ * Y position of VI sensor focal point in body frame (right axis with origin relative to vehicle centre of gravity)
  *
  * @group EKF2
  * @unit m
@@ -945,7 +945,7 @@ PARAM_DEFINE_FLOAT(EKF2_EV_POS_X, 0.0f);
 PARAM_DEFINE_FLOAT(EKF2_EV_POS_Y, 0.0f);
 
 /**
- * Z position of VI sensor focal point in body frame
+ * Z position of VI sensor focal point in body frame (down axis with origin relative to vehicle centre of gravity)
  *
  * @group EKF2
  * @unit m