diff --git a/conf/autopilot/subsystems/fixedwing/ahrs_float_dcm.makefile b/conf/autopilot/subsystems/fixedwing/ahrs_float_dcm.makefile
index 8020cc652a..2369faecb8 100644
--- a/conf/autopilot/subsystems/fixedwing/ahrs_float_dcm.makefile
+++ b/conf/autopilot/subsystems/fixedwing/ahrs_float_dcm.makefile
@@ -3,11 +3,10 @@
 # attitude estimation for fixedwings via dcm algorithm
 
 
-$(TARGET).CFLAGS += -DAHRS_TYPE_H=\"subsystems/ahrs/ahrs_float_dcm.h\"
-$(TARGET).CFLAGS += -DUSE_AHRS_ALIGNER
-
 ifeq ($(TARGET), ap)
 
+ap.CFLAGS += -DAHRS_TYPE_H=\"subsystems/ahrs/ahrs_float_dcm.h\"
+ap.CFLAGS += -DUSE_AHRS_ALIGNER
 ap.CFLAGS += -DUSE_AHRS
 
 ap.srcs   += $(SRC_SUBSYSTEMS)/ahrs.c
@@ -37,7 +36,10 @@ ap.CFLAGS += -DAHRS_CORRECT_FREQUENCY=$(AHRS_CORRECT_FREQUENCY)
 
 endif
 
-# since there is currently no SITL sim for the Analog IMU, we use the infrared sim
+
+
+# since there is currently no SITL sim for the IMU, we use the infrared sim
+# and the ahrs_infrared subsystem
 
 ifeq ($(TARGET), sim)
 
@@ -51,6 +53,13 @@ sim.srcs += subsystems/sensors/infrared_adc.c
 sim.srcs += $(SRC_ARCH)/sim_ir.c
 sim.srcs += $(SRC_ARCH)/sim_imu.c
 
+
+sim.CFLAGS += -DAHRS_TYPE_H=\"subsystems/ahrs/ahrs_infrared.h\"
+sim.CFLAGS += -DUSE_AHRS
+
+sim.srcs   += $(SRC_SUBSYSTEMS)/ahrs.c
+sim.srcs   += $(SRC_SUBSYSTEMS)/ahrs/ahrs_infrared.c
+
 endif
 
 jsbsim.srcs += $(SRC_ARCH)/jsbsim_ir.c
diff --git a/conf/autopilot/subsystems/fixedwing/ahrs_int_cmpl_euler.makefile b/conf/autopilot/subsystems/fixedwing/ahrs_int_cmpl_euler.makefile
index d66dd0183c..dbee272c3e 100644
--- a/conf/autopilot/subsystems/fixedwing/ahrs_int_cmpl_euler.makefile
+++ b/conf/autopilot/subsystems/fixedwing/ahrs_int_cmpl_euler.makefile
@@ -17,8 +17,32 @@ AHRS_SRCS   += subsystems/ahrs/ahrs_aligner.c
 ap.CFLAGS += $(AHRS_CFLAGS)
 ap.srcs += $(AHRS_SRCS)
 
-sim.CFLAGS += $(AHRS_CFLAGS)
-sim.srcs += $(AHRS_SRCS)
+
+
+# since there is currently no ocaml SITL sim for the IMU, we use the infrared sim
+# and the ahrs_infrared subsystem
+
+ifeq ($(TARGET), sim)
+
+sim.CFLAGS += -DIR_ROLL_NEUTRAL_DEFAULT=0
+sim.CFLAGS += -DIR_PITCH_NEUTRAL_DEFAULT=0
+
+sim.CFLAGS += -DUSE_INFRARED
+sim.srcs += subsystems/sensors/infrared.c
+sim.srcs += subsystems/sensors/infrared_adc.c
+
+sim.srcs += $(SRC_ARCH)/sim_ir.c
+sim.srcs += $(SRC_ARCH)/sim_imu.c
+
+
+sim.CFLAGS += -DAHRS_TYPE_H=\"subsystems/ahrs/ahrs_infrared.h\"
+sim.CFLAGS += -DUSE_AHRS
+
+sim.srcs   += $(SRC_SUBSYSTEMS)/ahrs.c
+sim.srcs   += $(SRC_SUBSYSTEMS)/ahrs/ahrs_infrared.c
+
+endif
+
 
 
 # Extra stuff for fixedwings
diff --git a/conf/autopilot/subsystems/fixedwing/ahrs_int_cmpl_quat.makefile b/conf/autopilot/subsystems/fixedwing/ahrs_int_cmpl_quat.makefile
index 7f2ef85695..7b5962b0f8 100644
--- a/conf/autopilot/subsystems/fixedwing/ahrs_int_cmpl_quat.makefile
+++ b/conf/autopilot/subsystems/fixedwing/ahrs_int_cmpl_quat.makefile
@@ -20,8 +20,31 @@ AHRS_SRCS   += subsystems/ahrs/ahrs_aligner.c
 ap.CFLAGS += $(AHRS_CFLAGS)
 ap.srcs += $(AHRS_SRCS)
 
-sim.CFLAGS += $(AHRS_CFLAGS)
-sim.srcs += $(AHRS_SRCS)
+
+
+# since there is currently no ocaml SITL sim for the IMU, we use the infrared sim
+# and the ahrs_infrared subsystem
+
+ifeq ($(TARGET), sim)
+
+sim.CFLAGS += -DIR_ROLL_NEUTRAL_DEFAULT=0
+sim.CFLAGS += -DIR_PITCH_NEUTRAL_DEFAULT=0
+
+sim.CFLAGS += -DUSE_INFRARED
+sim.srcs += subsystems/sensors/infrared.c
+sim.srcs += subsystems/sensors/infrared_adc.c
+
+sim.srcs += $(SRC_ARCH)/sim_ir.c
+sim.srcs += $(SRC_ARCH)/sim_imu.c
+
+
+sim.CFLAGS += -DAHRS_TYPE_H=\"subsystems/ahrs/ahrs_infrared.h\"
+sim.CFLAGS += -DUSE_AHRS
+
+sim.srcs   += $(SRC_SUBSYSTEMS)/ahrs.c
+sim.srcs   += $(SRC_SUBSYSTEMS)/ahrs/ahrs_infrared.c
+
+endif
 
 
 # Extra stuff for fixedwings
diff --git a/sw/airborne/ap_downlink.h b/sw/airborne/ap_downlink.h
index da8d98444a..a7f5962a03 100644
--- a/sw/airborne/ap_downlink.h
+++ b/sw/airborne/ap_downlink.h
@@ -124,6 +124,7 @@
 #endif
 
 #if defined USE_INFRARED || USE_INFRARED_TELEMETRY
+#include "subsystems/sensors/infrared.h"
 #define PERIODIC_SEND_IR_SENSORS(_chan) DOWNLINK_SEND_IR_SENSORS(_chan, &infrared.value.ir1, &infrared.value.ir2, &infrared.pitch, &infrared.roll, &infrared.top);
 #else
 #define PERIODIC_SEND_IR_SENSORS(_chan) ;
diff --git a/sw/airborne/arch/sim/sim_imu.c b/sw/airborne/arch/sim/sim_imu.c
index 0169091122..7ec14cf240 100644
--- a/sw/airborne/arch/sim/sim_imu.c
+++ b/sw/airborne/arch/sim/sim_imu.c
@@ -6,7 +6,6 @@
 
 
 #include <inttypes.h>
-#include "subsystems/sensors/infrared.h"
 #include "generated/airframe.h"
 
 #include <caml/mlvalues.h>
diff --git a/sw/airborne/subsystems/ahrs/ahrs_infrared.h b/sw/airborne/subsystems/ahrs/ahrs_infrared.h
index 0972c7cebd..82fe3109ad 100644
--- a/sw/airborne/subsystems/ahrs/ahrs_infrared.h
+++ b/sw/airborne/subsystems/ahrs/ahrs_infrared.h
@@ -25,6 +25,12 @@
 #include "subsystems/ahrs.h"
 #include "std.h"
 
+// TODO: harmonize infrared neutrals with ins_neutrals
+// or get rid of ins neutrals
+// this ins only needed for sim right now
+extern float ins_roll_neutral;
+extern float ins_pitch_neutral;
+
 extern void ahrs_update_gps(void);
 extern void ahrs_update_infrared(void);