From 047fddbcd8b9fa6d6cee7908c0d2865e005088ef Mon Sep 17 00:00:00 2001
From: Jacob Dahl <37091262+dakejahl@users.noreply.github.com>
Date: Sat, 4 Apr 2026 00:02:21 -0800
Subject: [PATCH] fix(sensors): fix baro publish rate limiter aliasing (#26967)

Use timestamp_sample instead of time_now_us for the rate limiter check
to sync to the sensor clock rather than the wall clock.

Switch from direct timestamp assignment to epoch-advance
(_last_publication_timestamp += interval_us) with a catch-up guard to
prevent aliasing artifacts when the sensor sample rate is close to the
configured publication rate.
---
 src/modules/sensors/vehicle_air_data/VehicleAirData.cpp | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/modules/sensors/vehicle_air_data/VehicleAirData.cpp b/src/modules/sensors/vehicle_air_data/VehicleAirData.cpp
index 9c4fe75ece..13c17b197d 100644
--- a/src/modules/sensors/vehicle_air_data/VehicleAirData.cpp
+++ b/src/modules/sensors/vehicle_air_data/VehicleAirData.cpp
@@ -274,7 +274,7 @@ void VehicleAirData::Run()
 
 				const hrt_abstime timestamp_sample = _timestamp_sample_sum[instance] / _data_sum_count[instance];
 
-				if (time_now_us >= _last_publication_timestamp[instance] + interval_us) {
+				if (timestamp_sample >= _last_publication_timestamp[instance] + interval_us) {
 
 					bool publish = (time_now_us <= timestamp_sample + 1_s);
 
@@ -312,7 +312,12 @@ void VehicleAirData::Run()
 						_vehicle_air_data_pub.publish(out);
 					}
 
-					_last_publication_timestamp[instance] = time_now_us;
+					// epoch-advance to prevent aliasing; catch up if more than one interval behind
+					_last_publication_timestamp[instance] += interval_us;
+
+					if (timestamp_sample > _last_publication_timestamp[instance] + interval_us) {
+						_last_publication_timestamp[instance] = timestamp_sample;
+					}
 
 					// reset
 					_timestamp_sample_sum[instance] = 0;