From 336d055923e291e6f8f9c5f3f0fdf923027e02c9 Mon Sep 17 00:00:00 2001
From: Niklas Hauser <121870655+niklaut@users.noreply.github.com>
Date: Fri, 28 Feb 2025 21:14:32 +0100
Subject: [PATCH] Robustify Ulanding Radar (#24333)

* [ulanding_radar] Fix comms error perf counter usage

* [ulanding_radar] Workaround for lost messages by lowering sampling rate

The current implementation of the Aerotenna uLanding radar driver assumes that
the UART frames are received in full. If the driver polls with 10ms this is not
always the case and the driver will fail to parse the frame leading to
significant packet loss. This workaround polls at 12ms which ensures that at
least one entire frame is received.
---
 .../distance_sensor/ulanding_radar/AerotennaULanding.cpp   | 7 ++++++-
 .../distance_sensor/ulanding_radar/AerotennaULanding.hpp   | 2 +-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/drivers/distance_sensor/ulanding_radar/AerotennaULanding.cpp b/src/drivers/distance_sensor/ulanding_radar/AerotennaULanding.cpp
index 6558aef348..ffd2c81a7a 100644
--- a/src/drivers/distance_sensor/ulanding_radar/AerotennaULanding.cpp
+++ b/src/drivers/distance_sensor/ulanding_radar/AerotennaULanding.cpp
@@ -125,10 +125,15 @@ int AerotennaULanding::collect()
 
 			index--;
 		}
+
+	} else {
+		return -EAGAIN;
 	}
 
 	if (!checksum_passed) {
-		return -EAGAIN;
+		perf_count(_comms_errors);
+		perf_end(_sample_perf);
+		return -EBADMSG;
 	}
 
 	_px4_rangefinder.update(timestamp_sample, distance_m);
diff --git a/src/drivers/distance_sensor/ulanding_radar/AerotennaULanding.hpp b/src/drivers/distance_sensor/ulanding_radar/AerotennaULanding.hpp
index dc133254bf..98d1c0ab90 100644
--- a/src/drivers/distance_sensor/ulanding_radar/AerotennaULanding.hpp
+++ b/src/drivers/distance_sensor/ulanding_radar/AerotennaULanding.hpp
@@ -56,7 +56,7 @@
 
 using namespace time_literals;
 
-#define ULANDING_MEASURE_INTERVAL       10_ms
+#define ULANDING_MEASURE_INTERVAL       12_ms
 #define ULANDING_MAX_DISTANCE	        50.0f
 #define ULANDING_MIN_DISTANCE	        0.315f
 #define ULANDING_VERSION	        1