diff --git a/libraries/SITL/SIM_RF_GYUS42v2.cpp b/libraries/SITL/SIM_RF_GYUS42v2.cpp
new file mode 100644
index 0000000000..0ab5c40ce9
--- /dev/null
+++ b/libraries/SITL/SIM_RF_GYUS42v2.cpp
@@ -0,0 +1,43 @@
+/*
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+/*
+  Simulator for the GYUS42v2 Serial rangefinder
+*/
+
+#include "SIM_RF_GYUS42v2.h"
+
+#include <stdio.h>
+#include <string.h>
+
+using namespace SITL;
+
+uint32_t RF_GYUS42v2::packet_for_alt(uint16_t alt_cm, uint8_t *buffer, uint8_t buflen)
+{
+    if (buflen < 7) {
+        return 0;
+    }
+    buffer[0] = 0x5A;
+    buffer[1] = 0; // FIXME
+    buffer[2] = 0; // FIXME
+    buffer[3] = 0; // FIXME
+    buffer[4] = alt_cm >> 8;
+    buffer[5] = alt_cm & 0xFF;
+    buffer[6] = 0;
+    for (uint8_t i=0; i<6; i++) {
+        buffer[6] += buffer[i];
+    }
+
+    return 7;
+}
diff --git a/libraries/SITL/SIM_RF_GYUS42v2.h b/libraries/SITL/SIM_RF_GYUS42v2.h
new file mode 100644
index 0000000000..308123dd18
--- /dev/null
+++ b/libraries/SITL/SIM_RF_GYUS42v2.h
@@ -0,0 +1,48 @@
+/*
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+/*
+  Simulator for the GY-US42-v2 serial rangefinder
+
+./Tools/autotest/sim_vehicle.py --gdb --debug -v ArduCopter -A --uartF=sim:gyus42v2 --speedup=1
+
+param set SERIAL5_PROTOCOL 9
+param set RNGFND1_TYPE 31
+graph RANGEFINDER.distance
+graph GLOBAL_POSITION_INT.relative_alt/1000-RANGEFINDER.distance
+reboot
+
+arm throttle
+rc 3 1600
+*/
+
+#pragma once
+
+#include "SIM_SerialRangeFinder.h"
+
+namespace SITL {
+
+class RF_GYUS42v2 : public SerialRangeFinder {
+public:
+
+    uint32_t packet_for_alt(uint16_t alt_cm, uint8_t *buffer, uint8_t buflen) override;
+
+    // TODO: work this out
+    uint16_t reading_interval_ms() const override { return 100; }
+
+private:
+
+};
+
+}