diff --git a/libraries/AP_Math/chirp.cpp b/libraries/AP_Math/chirp.cpp
new file mode 100644
index 0000000000..b01250bca6
--- /dev/null
+++ b/libraries/AP_Math/chirp.cpp
@@ -0,0 +1,87 @@
+/*
+ * chirp.cpp
+ *
+ * Copyright (C) Leonard Hall 2020
+ *
+ * This file 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 file 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 .
+ */
+
+/*
+* This object generates a chirp signal based on the input variables. A chirp is
+* a sine wave starting from the minimum frequency and ending at the maximum frequency.
+* The progression in frequency is not linear but designed to increase exponentially.
+* The chirp can be designed to dwell at the minimum frequency for a specified time
+* before sweeping through the frequencies and also can fade in the magnitude at the
+* beginning and fade out the magnitude at the end. This object can also generate
+* constant frequency sine waves by setting the minimum and maximum frequency to the
+* same value.
+*/
+#include
+#include "chirp.h"
+
+// constructor
+Chirp::Chirp() {}
+
+// initializes the chirp object
+void Chirp::init(float time_record, float frequency_start_hz, float frequency_stop_hz, float time_fade_in, float time_fade_out, float time_const_freq)
+{
+ // pass in variables to class
+ record = time_record;
+ wMin = M_2PI * frequency_start_hz;
+ wMax = M_2PI * frequency_stop_hz;
+ fade_in = time_fade_in;
+ fade_out = time_fade_out;
+ const_freq = time_const_freq;
+
+ B = logf(wMax / wMin);
+
+}
+
+// determine chirp signal output at the specified time and amplitude
+float Chirp::update(float time, float waveform_magnitude)
+{
+ magnitude = waveform_magnitude;
+ if (time <= 0.0f) {
+ window = 0.0f;
+ } else if (time <= fade_in) {
+ window = 0.5 - 0.5 * cosf(M_PI * time / fade_in);
+ } else if (time <= record - fade_out) {
+ window = 1.0;
+ } else if (time <= record) {
+ window = 0.5 - 0.5 * cosf(M_PI * (time - (record - fade_out)) / fade_out + M_PI);
+ } else {
+ window = 0.0;
+ }
+
+ if (time <= 0.0f) {
+ waveform_freq_rads = wMin;
+ output = 0.0f;
+ } else if (time <= const_freq) {
+ waveform_freq_rads = wMin;
+ output = window * magnitude * sinf(wMin * time - wMin * const_freq);
+ } else if (time <= record) {
+ // handles constant frequency dwells and chirps
+ if (is_equal(wMin, wMax)) {
+ waveform_freq_rads = wMin;
+ output = window * magnitude * sinf(wMin * time);
+ } else {
+ waveform_freq_rads = wMin * expf(B * (time - const_freq) / (record - const_freq));
+ output = window * magnitude * sinf((wMin * (record - const_freq) / B) * (expf(B * (time - const_freq) / (record - const_freq)) - 1));
+ }
+ } else {
+ waveform_freq_rads = wMax;
+ output = 0.0f;
+ }
+ return output;
+}
diff --git a/libraries/AP_Math/chirp.h b/libraries/AP_Math/chirp.h
new file mode 100644
index 0000000000..23487e21e5
--- /dev/null
+++ b/libraries/AP_Math/chirp.h
@@ -0,0 +1,53 @@
+#pragma once
+
+class Chirp {
+
+public:
+
+ // constructor
+ Chirp();
+
+ // initializes the chirp object
+ void init(float time_record, float frequency_start_hz, float frequency_stop_hz, float time_fade_in, float time_fade_out, float time_const_freq);
+
+ // determine chirp signal output at the specified time and amplitude
+ float update(float time, float waveform_magnitude);
+
+ // accessor for the current waveform frequency
+ float get_frequency_rads() {return waveform_freq_rads; }
+
+private:
+ // Total chirp length in seconds
+ float record;
+
+ // Chirp oscillation amplitude
+ float magnitude;
+
+ // Chirp start frequency in rad/s
+ float wMin;
+
+ // Chirp end frequency in rad/s
+ float wMax;
+
+ // Amplitude fade in time in seconds
+ float fade_in;
+
+ // Amplitude fade out time in seconds
+ float fade_out;
+
+ // Time that chirp will remain at the min frequency before increasing to max frequency
+ float const_freq;
+
+ // frequency ratio
+ float B;
+
+ // current waveform frequency in rad/s
+ float waveform_freq_rads;
+
+ // current amplitude of chirp
+ float window;
+
+ // output of chirp signal at the requested time
+ float output;
+
+};