Add bottom_clearance to altitude in telemetry

src/mavsdk/plugins/telemetry/include/plugins/telemetry/telemetry.h

@@ -968,6 +968,9 @@ class Telemetry : public PluginBase {
         float altitude_local_m{float(NAN)}; /**< @brief Local altitude in meters */
         float altitude_relative_m{float(NAN)}; /**< @brief Altitude above home position in meters */
         float altitude_terrain_m{float(NAN)}; /**< @brief Altitude above terrain in meters */
+        float bottom_clearance_m{
+            float(NAN)}; /**< @brief This is not the altitude, but the clear space below the system
+                            according to the fused clearance estimate in meters. */
     };
 
     /**

src/mavsdk/plugins/telemetry/telemetry.cpp

@@ -1486,7 +1486,9 @@ bool operator==(const Telemetry::Altitude& lhs, const Telemetry::Altitude& rhs)
            ((std::isnan(rhs.altitude_relative_m) && std::isnan(lhs.altitude_relative_m)) ||
             rhs.altitude_relative_m == lhs.altitude_relative_m) &&
            ((std::isnan(rhs.altitude_terrain_m) && std::isnan(lhs.altitude_terrain_m)) ||
-            rhs.altitude_terrain_m == lhs.altitude_terrain_m);
+            rhs.altitude_terrain_m == lhs.altitude_terrain_m) &&
+           ((std::isnan(rhs.bottom_clearance_m) && std::isnan(lhs.bottom_clearance_m)) ||
+            rhs.bottom_clearance_m == lhs.bottom_clearance_m);
 }
 
 std::ostream& operator<<(std::ostream& str, Telemetry::Altitude const& altitude)
@@ -1498,6 +1500,7 @@ std::ostream& operator<<(std::ostream& str, Telemetry::Altitude const& altitude)
     str << "    altitude_local_m: " << altitude.altitude_local_m << '\n';
     str << "    altitude_relative_m: " << altitude.altitude_relative_m << '\n';
     str << "    altitude_terrain_m: " << altitude.altitude_terrain_m << '\n';
+    str << "    bottom_clearance_m: " << altitude.bottom_clearance_m << '\n';
     str << '}';
     return str;
 }

src/mavsdk/plugins/telemetry/telemetry_impl.cpp

@@ -842,6 +842,7 @@ void TelemetryImpl::process_altitude(const mavlink_message_t& message)
     new_altitude.altitude_local_m = mavlink_altitude.altitude_local;
     new_altitude.altitude_relative_m = mavlink_altitude.altitude_relative;
     new_altitude.altitude_terrain_m = mavlink_altitude.altitude_terrain;
+    new_altitude.bottom_clearance_m = mavlink_altitude.bottom_clearance;
 
     set_altitude(new_altitude);
 

src/mavsdk_server/src/plugins/telemetry/telemetry_service_impl.h

@@ -1267,6 +1267,8 @@ class TelemetryServiceImpl final : public rpc::telemetry::TelemetryService::Serv
 
         rpc_obj->set_altitude_terrain_m(altitude.altitude_terrain_m);
 
+        rpc_obj->set_bottom_clearance_m(altitude.bottom_clearance_m);
+
         return rpc_obj;
     }
 
@@ -1285,6 +1287,8 @@ class TelemetryServiceImpl final : public rpc::telemetry::TelemetryService::Serv
 
         obj.altitude_terrain_m = altitude.altitude_terrain_m();
 
+        obj.bottom_clearance_m = altitude.bottom_clearance_m();
+
         return obj;
     }