From 01193bf86bba92e003039372d01ee80c30dfd0bf Mon Sep 17 00:00:00 2001
From: Mahima Yoga <mahima@auterion.com>
Date: Wed, 22 Jul 2026 15:22:52 +0200
Subject: [PATCH] fix(simulation): make wind affect the airspeed sensor in gz
 (#28042)

* feat(simulation): load gz WindEffects system globally

Nothing published the world wind (wind_info topic / wind entity
velocity) so far, leaving the airspeed sensor and drag systems without
wind data in worlds that define one.

No effect in worlds without a wind definition.

Signed-off-by: mahima-yoga <mahima@auterion.com>

* fix(simulation): read wind from the ECM in the gz airspeed plugin

The wind_info topic is only published when the wind changes, so a model
that spawns after the world has loaded misses it and simulates a
wind-blind pitot: so the EKF never estimates the wind. Read the wind entity
velocity from the EntityComponentManager each step instead.

Signed-off-by: mahima-yoga <mahima@auterion.com>

---------

Signed-off-by: mahima-yoga <mahima@auterion.com>
---
 src/modules/simulation/gz_bridge/server.config    |  1 +
 .../simulation/gz_plugins/airspeed/AirSpeed.cpp   | 15 +++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/src/modules/simulation/gz_bridge/server.config b/src/modules/simulation/gz_bridge/server.config
index 0001356a3a8..b1f88198f63 100644
--- a/src/modules/simulation/gz_bridge/server.config
+++ b/src/modules/simulation/gz_bridge/server.config
@@ -8,6 +8,7 @@
     <plugin entity_name="*" entity_type="world" filename="gz-sim-air-pressure-system" name="gz::sim::systems::AirPressure"/>
     <plugin entity_name="*" entity_type="world" filename="gz-sim-air-speed-system" name="gz::sim::systems::AirSpeed"/>
     <plugin entity_name="*" entity_type="world" filename="gz-sim-apply-link-wrench-system" name="gz::sim::systems::ApplyLinkWrench"/>
+    <plugin entity_name="*" entity_type="world" filename="gz-sim-wind-effects-system" name="gz::sim::systems::WindEffects"/>
     <plugin entity_name="*" entity_type="world" filename="gz-sim-navsat-system" name="gz::sim::systems::NavSat"/>
     <plugin entity_name="*" entity_type="world" filename="gz-sim-magnetometer-system" name="gz::sim::systems::Magnetometer"/>
     <plugin entity_name="*" entity_type="world" filename="gz-sim-sensors-system" name="gz::sim::systems::Sensors">
diff --git a/src/modules/simulation/gz_plugins/airspeed/AirSpeed.cpp b/src/modules/simulation/gz_plugins/airspeed/AirSpeed.cpp
index 8d0c74dab70..103533de1ac 100644
--- a/src/modules/simulation/gz_plugins/airspeed/AirSpeed.cpp
+++ b/src/modules/simulation/gz_plugins/airspeed/AirSpeed.cpp
@@ -35,6 +35,8 @@
 
 #include <gz/plugin/Register.hh>
 #include <gz/msgs/air_speed.pb.h>
+#include <gz/sim/components/LinearVelocity.hh>
+#include <gz/sim/components/Wind.hh>
 
 using namespace px4;
 
@@ -120,6 +122,19 @@ void AirSpeed::PreUpdate(const gz::sim::UpdateInfo &_info,
 
 	// Calculate differential pressure + noise in hPa
 	const float diff_pressure_noise = standard_normal_distribution_(random_generator_) * diff_pressure_stddev_;
+
+	// Read the wind from the ECM: the wind_info topic is only published on wind changes,
+	// which the subscription misses when the model spawns after the world was loaded
+	const gz::sim::Entity wind_entity = _ecm.EntityByComponents(gz::sim::components::Wind());
+
+	if (wind_entity != gz::sim::kNullEntity) {
+		const auto wind_linear_velocity = _ecm.Component<gz::sim::components::WorldLinearVelocity>(wind_entity);
+
+		if (wind_linear_velocity) {
+			_wind_velocity = wind_linear_velocity->Data();
+		}
+	}
+
 	// Body-relateive air velocity
 	gz::math::Vector3d air_relative_velocity = _vehicle_velocity - _wind_velocity;
 	gz::math::Vector3d body_velocity = _vehicle_attitude.RotateVectorReverse(air_relative_velocity);