diff --git a/AntennaTracker/AntennaTracker.cpp b/AntennaTracker/AntennaTracker.cpp
index b69eca0be7..4fb3c2d711 100644
--- a/AntennaTracker/AntennaTracker.cpp
+++ b/AntennaTracker/AntennaTracker.cpp
@@ -127,19 +127,4 @@ Tracker::Tracker(void)
 
 Tracker tracker;
 
-/*
-  compatibility with old pde style build
- */
-void setup(void);
-void loop(void);
-
-void setup(void)
-{
-    tracker.setup();
-}
-void loop(void)
-{
-    tracker.loop();
-}
-
-AP_HAL_MAIN();
+AP_HAL_MAIN_CALLBACKS(&tracker);
diff --git a/AntennaTracker/Tracker.h b/AntennaTracker/Tracker.h
index feaec24521..c4a198575e 100644
--- a/AntennaTracker/Tracker.h
+++ b/AntennaTracker/Tracker.h
@@ -76,21 +76,16 @@
 #include "Parameters.h"
 #include <GCS_MAVLink/GCS.h>
 
-#include <AP_HAL_AVR/AP_HAL_AVR.h>
-#include <AP_HAL_SITL/AP_HAL_SITL.h>
-#include <AP_HAL_PX4/AP_HAL_PX4.h>
-#include <AP_HAL_FLYMAPLE/AP_HAL_FLYMAPLE.h>
-#include <AP_HAL_Linux/AP_HAL_Linux.h>
-#include <AP_HAL_Empty/AP_HAL_Empty.h>
-
-class Tracker {
+class Tracker : public AP_HAL::HAL::Callbacks {
 public:
     friend class GCS_MAVLINK;
     friend class Parameters;
 
     Tracker(void);
-    void setup();
-    void loop();
+
+    // HAL::Callbacks implementation.
+    void setup() override;
+    void loop() override;
 
 private:
     const AP_InertialSensor::Sample_rate ins_sample_rate = AP_InertialSensor::RATE_50HZ;