diff --git a/libraries/AP_HAL_SITL/DSP.cpp b/libraries/AP_HAL_SITL/DSP.cpp
index b8ca324342..b176c0c14b 100644
--- a/libraries/AP_HAL_SITL/DSP.cpp
+++ b/libraries/AP_HAL_SITL/DSP.cpp
@@ -137,6 +137,13 @@ void DSP::vector_scale_float(const float* vin, float scale, float* vout, uint16_
     }
 }
 
+void DSP::vector_add_float(const float* vin1, const float* vin2, float* vout, uint16_t len) const
+{
+    for (uint16_t i = 0; i < len; i++) {
+        vout[i] = vin1[i] + vin2[i];
+    }
+}
+
 float DSP::vector_mean_float(const float* vin, uint16_t len) const
 {
     float mean_value = 0.0f;
diff --git a/libraries/AP_HAL_SITL/DSP.h b/libraries/AP_HAL_SITL/DSP.h
index 04bb410a61..6d7421e31f 100644
--- a/libraries/AP_HAL_SITL/DSP.h
+++ b/libraries/AP_HAL_SITL/DSP.h
@@ -52,5 +52,6 @@ private:
     void vector_max_float(const float* vin, uint16_t len, float* maxValue, uint16_t* maxIndex) const override;
     void vector_scale_float(const float* vin, float scale, float* vout, uint16_t len) const override;
     float vector_mean_float(const float* vin, uint16_t len) const override;
+    void vector_add_float(const float* vin1, const float* vin2, float* vout, uint16_t len) const override;
     void calculate_fft(complexf* f, uint16_t length);
 };