diff --git a/Tools/AP_Periph/AP_Periph.h b/Tools/AP_Periph/AP_Periph.h
index 3b8d18b044..4fa3f664cc 100644
--- a/Tools/AP_Periph/AP_Periph.h
+++ b/Tools/AP_Periph/AP_Periph.h
@@ -383,6 +383,13 @@ public:
         bool locked;
     } uart_monitor;
 #endif
+
+#if AP_SIM_ENABLED
+    SITL::SIM sitl;
+#if AP_AHRS_ENABLED
+    AP_AHRS ahrs;
+#endif
+#endif
 };
 
 namespace AP
diff --git a/Tools/AP_Periph/Parameters.cpp b/Tools/AP_Periph/Parameters.cpp
index d7702a8bdc..6e4ce775ea 100644
--- a/Tools/AP_Periph/Parameters.cpp
+++ b/Tools/AP_Periph/Parameters.cpp
@@ -569,6 +569,18 @@ const AP_Param::Info AP_Periph_FW::var_info[] = {
     GOBJECT(g_rcin, "RC",  Parameters_RCIN),
 #endif
 
+#if AP_SIM_ENABLED
+    // @Group: SIM_
+    // @Path: ../libraries/SITL/SITL.cpp
+    GOBJECT(sitl, "SIM_", SITL::SIM),
+
+#if AP_AHRS_ENABLED
+    // @Group: AHRS_
+    // @Path: ../libraries/AP_AHRS/AP_AHRS.cpp
+    GOBJECT(ahrs,                   "AHRS_",    AP_AHRS),
+#endif
+#endif // AP_SIM_ENABLED
+    
     AP_VAREND
 };
 
diff --git a/Tools/AP_Periph/Parameters.h b/Tools/AP_Periph/Parameters.h
index 7e7c96dd6a..03b9ba6282 100644
--- a/Tools/AP_Periph/Parameters.h
+++ b/Tools/AP_Periph/Parameters.h
@@ -79,6 +79,8 @@ public:
         k_param_networking,
         k_param_rpm_sensor,
         k_param_g_rcin,
+        k_param_sitl,
+        k_param_ahrs,
     };
 
     AP_Int16 format_version;
diff --git a/Tools/AP_Periph/can.cpp b/Tools/AP_Periph/can.cpp
index 5dfc37c307..d35568f4f4 100644
--- a/Tools/AP_Periph/can.cpp
+++ b/Tools/AP_Periph/can.cpp
@@ -2456,7 +2456,7 @@ void AP_Periph_FW::can_rangefinder_update(void)
     uint32_t now = AP_HAL::millis();
     static uint32_t last_update_ms;
     if (g.rangefinder_max_rate > 0 &&
-        now - last_update_ms < 1000/g.rangefinder_max_rate) {
+        now - last_update_ms < uint32_t(1000/g.rangefinder_max_rate)) {
         // limit to max rate
         return;
     }
diff --git a/Tools/AP_Periph/wscript b/Tools/AP_Periph/wscript
index 4b87fa5bcd..f3fcdaa41a 100644
--- a/Tools/AP_Periph/wscript
+++ b/Tools/AP_Periph/wscript
@@ -73,6 +73,9 @@ def build(bld):
                      'AP_RPM',
                      'AP_Proximity',
                      'AP_RCProtocol',
+                     'AP_AHRS',
+                     'AP_Terrain',
+                     'AP_Torqeedo',
                      ]
     bld.ap_stlib(
         name= 'AP_Periph_libs',