airspeed: Prevent the filter from overshooting into the negative airspeed range

1 files changed, 16 insertions, 4 deletions

diff --git a/src/lib/mathlib/math/filter/LowPassFilter2p.hpp b/src/lib/mathlib/math/filter/LowPassFilter2p.hpp
index 208ec98d4..74cd5d78c 100644
--- a/src/lib/mathlib/math/filter/LowPassFilter2p.hpp
+++ b/src/lib/mathlib/math/filter/LowPassFilter2p.hpp
@@ -52,18 +52,30 @@ public:
         _delay_element_1 = _delay_element_2 = 0;
     }
 
-    // change parameters
+    /**
+     * Change filter parameters
+     */
     void set_cutoff_frequency(float sample_freq, float cutoff_freq);
 
-    // apply - Add a new raw value to the filter 
-    // and retrieve the filtered result
+    /**
+     * Add a new raw value to the filter
+     *
+     * @return retrieve the filtered result
+     */
     float apply(float sample);
 
-    // return the cutoff frequency
+    /**
+     * Return the cutoff frequency
+     */
     float get_cutoff_freq(void) const {
         return _cutoff_freq;
     }
 
+    /**
+     * Reset the filter state to this value
+     */
+    float reset(float sample);
+
 private:
     float           _cutoff_freq; 
     float           _a1;