refactor(sensors)!: replace SENS_DPRES_OFF with per-sensor calibration

SENS_DPRES_OFF applied one zero offset to whichever airspeed sensor
happened to come first, which cannot work once there is more than one
sensor. It is superseded by CAL_DPRESx_OFF.

BREAKING CHANGE: SENS_DPRES_OFF is removed. Ground stations that read it
to decide whether airspeed has been calibrated must check CAL_DPRES0_ID
instead, matching how CAL_MAG0_ID, CAL_GYRO0_ID and CAL_ACC0_ID are
already used.

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

ROMFS/px4fmu_common/init.d-posix/airframes/10043_sihsim_standard_vtol

@@ -80,7 +80,6 @@ param set-default MAV_TYPE 22
 # set SYS_HITL to 2 to start the SIH and avoid sensors startup
 # param set-default SYS_HITL 2
 
-param set-default SENS_DPRES_OFF 0.001
 
 param set SIH_T_MAX 2
 param set SIH_Q_MAX 0.0165

ROMFS/px4fmu_common/init.d-posix/rcS

@@ -155,7 +155,6 @@ param set-default CAL_MAG1_ID 197644
 param set-default CAL_MAG1_PRIO 50
 
 param set-default SENS_BOARD_X_OFF 0.000001
-param set-default SENS_DPRES_OFF 0.001
 
 param set-default BAT1_N_CELLS 4
 

ROMFS/px4fmu_common/init.d/airframes/1102_tailsitter_duo_sih.hil

@@ -64,7 +64,6 @@ param set-default SYS_HITL 2
 # - without real battery
 param set-default CBRK_SUPPLY_CHK 894281
 
-param set-default SENS_DPRES_OFF 0.001
 
 # tailsitter is equipped with two forward propellers
 param set SIH_F_T_MAX 2

ROMFS/px4fmu_common/init.d/airframes/1103_standard_vtol_sih.hil

@@ -76,7 +76,6 @@ param set-default SYS_HITL 2
 # - without real battery
 param set-default CBRK_SUPPLY_CHK 894281
 
-param set-default SENS_DPRES_OFF 0.001
 
 # quadrotor propellers
 param set SIH_T_MAX 2

src/lib/parameters/param_translation.cpp

@@ -75,6 +75,18 @@ param_modify_on_import_ret param_modify_on_import(bson_node_t node)
 		}
 	}
 
+	// 2026-09-16: SENS_DPRES_OFF (single global zero offset) replaced by the per-sensor
+	// CAL_DPRESx_OFF calibration. The value is carried into slot 0; the matching
+	// CAL_DPRES0_ID is claimed at runtime by the first airspeed sensor, because the device
+	// ID is not known at import time.
+	{
+		if (strcmp("SENS_DPRES_OFF", node->name) == 0) {
+			strcpy(node->name, "CAL_DPRES0_OFF");
+			PX4_INFO("copying %s -> %s", "SENS_DPRES_OFF", "CAL_DPRES0_OFF");
+			return param_modify_on_import_ret::PARAM_MODIFIED;
+		}
+	}
+
 	// 2024-04-15 SYS_MC_EST_GROUP removed
 	if ((node->type == bson_type_t::BSON_INT32) && (strcmp("SYS_MC_EST_GROUP", node->name) == 0)) {
 

src/modules/mavlink/mavlink_parameters.cpp

@@ -425,7 +425,6 @@ MavlinkParametersManager::send()
 		param_find("SENS_BOARD_X_OFF");
 		param_find("SENS_BOARD_Y_OFF");
 		param_find("SENS_BOARD_Z_OFF");
-		param_find("SENS_DPRES_OFF");
 		param_find("TRIG_MODE");
 		param_find("UAVCAN_ENABLE");
 

src/modules/sensors/sensor_params.yaml

@@ -2,14 +2,6 @@ module_name: sensors
 parameters:
 - group: Sensor Calibration
   definitions:
-    SENS_DPRES_OFF:
-      description:
-        short: Differential pressure sensor offset
-        long: The offset (zero-reading) in Pascal
-      category: System
-      type: float
-      default: 0.0
-      volatile: true
     SENS_DPRES_REV:
       description:
         short: Reverse differential pressure sensor readings

src/systemcmds/param/param.cpp

@@ -891,7 +891,7 @@ do_show_print_for_airframe(void *arg, param_t param)
 	}
 
 	if (!strncmp(p_name, "RC", 2) || !strncmp(p_name, "TC_", 3) || !strncmp(p_name, "CAL_", 4) ||
-		!strcmp(p_name, "SENS_DPRES_OFF") || !strcmp(p_name, "MAV_TYPE")) {
+		!strcmp(p_name, "MAV_TYPE")) {
 		return;
 	}