From 2223216ca262fa5f034cb0555a48322fc53ce9e6 Mon Sep 17 00:00:00 2001
From: Tom Pittenger <magicrub@gmail.com>
Date: Sun, 10 Jul 2016 16:51:37 -0700
Subject: [PATCH] AP_ADSB: add param ADSB_LIST_RADIUS to ignore distant
 aircraft

---
 libraries/AP_ADSB/AP_ADSB.cpp | 15 ++++++++++++++-
 libraries/AP_ADSB/AP_ADSB.h   | 10 ++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/libraries/AP_ADSB/AP_ADSB.cpp b/libraries/AP_ADSB/AP_ADSB.cpp
index e53ac623f4..39ebe1bb42 100644
--- a/libraries/AP_ADSB/AP_ADSB.cpp
+++ b/libraries/AP_ADSB/AP_ADSB.cpp
@@ -51,6 +51,13 @@ const AP_Param::GroupInfo AP_ADSB::var_info[] = {
     AP_GROUPINFO("LIST_MAX",   2, AP_ADSB, in_state.list_size_param, ADSB_VEHICLE_LIST_SIZE_DEFAULT),
 
 
+    // @Param: LIST_RADIUS
+    // @DisplayName: ADSB vehicle list radius filter
+    // @Description: ADSB vehicle list radius filter. Vehicles detected outside this radius will be completely ignored. They will not show up in the SRx_ADSB stream to the GCS and will not be considered in any avoidance calculations.
+    // @Range: 1 100000
+    // @User: Advanced
+    AP_GROUPINFO("LIST_RADIUS",   3, AP_ADSB, in_state.list_radius, ADSB_LIST_RADIUS_DEFAULT),
+
     AP_GROUPEND
 };
 
@@ -262,7 +269,13 @@ void AP_ADSB::update_vehicle(const mavlink_message_t* packet)
     adsb_vehicle_t vehicle {};
     mavlink_msg_adsb_vehicle_decode(packet, &vehicle.info);
 
-    if (find_index(vehicle, &index)) {
+    if (!_my_loc.is_zero() &&
+            _my_loc.get_distance(AP_ADSB::get_location(vehicle)) > in_state.list_radius) {
+
+        // vehicle is out of range. Ignore it.
+        return;
+
+    } else if (find_index(vehicle, &index)) {
 
         // found, update it
         set_vehicle(index, vehicle);
diff --git a/libraries/AP_ADSB/AP_ADSB.h b/libraries/AP_ADSB/AP_ADSB.h
index 988a67c8a7..c28d2f784d 100644
--- a/libraries/AP_ADSB/AP_ADSB.h
+++ b/libraries/AP_ADSB/AP_ADSB.h
@@ -25,12 +25,21 @@
 #include <AP_Common/AP_Common.h>
 #include <AP_Param/AP_Param.h>
 #include <GCS_MAVLink/GCS.h>
+#include <AP_Vehicle/AP_Vehicle.h>
+#include <AP_Common/Location.h>
 
 #define VEHICLE_THREAT_RADIUS_M         1000
 #define VEHICLE_TIMEOUT_MS              10000   // if no updates in this time, drop it from the list
 #define ADSB_VEHICLE_LIST_SIZE_DEFAULT  25
 #define ADSB_VEHICLE_LIST_SIZE_MAX      100
 
+
+#if APM_BUILD_TYPE(APM_BUILD_ArduPlane)
+    #define ADSB_LIST_RADIUS_DEFAULT        10000 // in meters
+#else // APM_BUILD_TYPE(APM_BUILD_ArduCopter), Rover, Boat
+    #define ADSB_LIST_RADIUS_DEFAULT        2000 // in meters
+#endif
+
 class AP_ADSB
 {
 public:
@@ -117,6 +126,7 @@ private:
         uint16_t    list_size = 1; // start with tiny list, then change to param-defined size. This ensures it doesn't fail on start
         adsb_vehicle_t *vehicle_list = nullptr;
         uint16_t    vehicle_count = 0;
+        AP_Int32    list_radius;
 
     // streamrate stuff
     uint32_t    send_start_ms[MAVLINK_COMM_NUM_BUFFERS];