From ca846443d10dd13f664e3f197d579913f8830d32 Mon Sep 17 00:00:00 2001
From: Andy Piper <github@andypiper.com>
Date: Tue, 22 Aug 2023 21:57:17 +0100
Subject: [PATCH] AP_NavEKF: fallback to no baro on boards that have no baro

---
 libraries/AP_NavEKF/AP_NavEKF_Source.cpp | 13 +++++++++++++
 libraries/AP_NavEKF/AP_NavEKF_Source.h   |  2 +-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/libraries/AP_NavEKF/AP_NavEKF_Source.cpp b/libraries/AP_NavEKF/AP_NavEKF_Source.cpp
index 633ee47b34..0f80af9f69 100644
--- a/libraries/AP_NavEKF/AP_NavEKF_Source.cpp
+++ b/libraries/AP_NavEKF/AP_NavEKF_Source.cpp
@@ -17,6 +17,7 @@
 #include <AP_Math/AP_Math.h>
 #include <AP_DAL/AP_DAL.h>
 #include <AP_Logger/AP_Logger.h>
+#include <AP_HAL/AP_HAL.h>
 
 extern const AP_HAL::HAL& hal;
 
@@ -231,6 +232,18 @@ AP_NavEKF_Source::SourceYaw AP_NavEKF_Source::getYawSource() const
     return _source_set[active_source_set].yaw;
 }
 
+// get pos Z source
+AP_NavEKF_Source::SourceZ AP_NavEKF_Source::getPosZSource() const
+{
+#ifdef HAL_BARO_ALLOW_INIT_NO_BARO
+    // check for special case of missing baro
+    if ((_source_set[active_source_set].posz == SourceZ::BARO) && (AP::dal().baro().num_instances() == 0)) {
+        return SourceZ::NONE;
+    }
+#endif
+    return _source_set[active_source_set].posz;
+}
+
 // align position of inactive sources to ahrs
 void AP_NavEKF_Source::align_inactive_sources()
 {
diff --git a/libraries/AP_NavEKF/AP_NavEKF_Source.h b/libraries/AP_NavEKF/AP_NavEKF_Source.h
index d07fb986fe..b8bfa67d18 100644
--- a/libraries/AP_NavEKF/AP_NavEKF_Source.h
+++ b/libraries/AP_NavEKF/AP_NavEKF_Source.h
@@ -55,7 +55,7 @@ public:
 
     // get current position source
     SourceXY getPosXYSource() const { return _source_set[active_source_set].posxy; }
-    SourceZ getPosZSource() const { return _source_set[active_source_set].posz; }
+    SourceZ getPosZSource() const;
 
     // set position, velocity and yaw sources to either 0=primary, 1=secondary, 2=tertiary
     void setPosVelYawSourceSet(uint8_t source_set_idx);