Added transponder plugin (#1390)

Add transponder plugin

Co-authored-by: Jonas Vautherin <jonas.vautherin@gmail.com>

examples/transponder/CMakeLists.txt

@@ -0,0 +1,23 @@
+cmake_minimum_required(VERSION 3.10.2)
+
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+project(transponder)
+
+if(NOT MSVC)
+    add_definitions("-Wall -Wextra")
+else()
+    add_definitions("-WX -W2")
+endif()
+
+find_package(MAVSDK REQUIRED)
+
+add_executable(transponder
+    transponder.cpp
+)
+
+target_link_libraries(transponder
+    MAVSDK::mavsdk_transponder
+    MAVSDK::mavsdk
+)

examples/transponder/transponder.cpp

@@ -0,0 +1,115 @@
+//
+// Simple example to demonstrate how to use the MAVSDK.
+//
+// Author:
+
+#include <chrono>
+#include <cstdint>
+#include <mavsdk/mavsdk.h>
+#include <mavsdk/plugins/transponder/transponder.h>
+#include <iostream>
+#include <future>
+#include <memory>
+#include <thread>
+
+using namespace mavsdk;
+using std::chrono::seconds;
+using std::this_thread::sleep_for;
+
+#define ERROR_CONSOLE_TEXT "\033[31m" // Turn text on console red
+#define TRANSPONDER_CONSOLE_TEXT "\033[34m" // Turn text on console blue
+#define NORMAL_CONSOLE_TEXT "\033[0m" // Restore normal console color
+
+void usage(std::string bin_name)
+{
+    std::cout << NORMAL_CONSOLE_TEXT << "Usage : " << bin_name << " <connection_url>" << std::endl
+              << "Connection URL format should be :" << std::endl
+              << " For TCP : tcp://[server_host][:server_port]" << std::endl
+              << " For UDP : udp://[bind_host][:bind_port]" << std::endl
+              << " For Serial : serial:///path/to/serial/dev[:baudrate]" << std::endl
+              << "For example, to connect to the simulator use URL: udp://:14540" << std::endl;
+}
+
+int main(int argc, char** argv)
+{
+    Mavsdk mavsdk;
+    std::string connection_url;
+    ConnectionResult connection_result;
+
+    if (argc == 2) {
+        connection_url = argv[1];
+        connection_result = mavsdk.add_any_connection(connection_url);
+    } else {
+        usage(argv[0]);
+        return 1;
+    }
+
+    if (connection_result != ConnectionResult::Success) {
+        std::cout << ERROR_CONSOLE_TEXT << "Connection failed: " << connection_result
+                  << NORMAL_CONSOLE_TEXT << std::endl;
+        return 1;
+    }
+
+    std::cout << "Waiting to discover system..." << std::endl;
+    auto prom = std::promise<std::shared_ptr<System>>{};
+    auto fut = prom.get_future();
+
+    mavsdk.subscribe_on_new_system([&mavsdk, &prom]() {
+        auto system = mavsdk.systems().back();
+
+        if (system->has_autopilot()) {
+            std::cout << "Discovered autopilot" << std::endl;
+
+            // Unsubscribe again as we only want to find one system.
+            mavsdk.subscribe_on_new_system(nullptr);
+            prom.set_value(system);
+        }
+    });
+
+    // We usually receive heartbeats at 1Hz, therefore we should find a
+    // system after around 3 seconds.
+    if (fut.wait_for(seconds(3)) == std::future_status::timeout) {
+        std::cout << ERROR_CONSOLE_TEXT << "No autopilot found, exiting." << NORMAL_CONSOLE_TEXT
+                  << std::endl;
+        return 1;
+    }
+
+    auto system = fut.get();
+
+    auto transponder = Transponder{system};
+
+    // We want to listen to the transponder of the drone at 1 Hz.
+    std::cout << "Setting transponder update rate" << std::endl;
+    const Transponder::Result set_rate_result = transponder.set_rate_transponder(1.0);
+    if (set_rate_result != Transponder::Result::Success) {
+        std::cout << ERROR_CONSOLE_TEXT << "Setting rate failed:" << set_rate_result
+                  << NORMAL_CONSOLE_TEXT << std::endl;
+        return 1;
+    }
+
+    // Set up callback to monitor transponder activity
+    std::cout << "Setting transponder subscription" << std::endl;
+    transponder.subscribe_transponder([](Transponder::AdsbVehicle adsbVehicle) {
+        std::cout << TRANSPONDER_CONSOLE_TEXT // set to blue
+                  << "ICAO Address: " << adsbVehicle.icao_address << std::endl
+                  << "Latitude: " << adsbVehicle.latitude_deg << " deg" << std::endl
+                  << "Longitude: " << adsbVehicle.longitude_deg << " deg" << std::endl
+                  << "Absolute Altitude: " << adsbVehicle.absolute_altitude_m << " m" << std::endl
+                  << "Heading: " << adsbVehicle.heading_deg << " deg" << std::endl
+                  << "Horizontal Velocity: " << adsbVehicle.horizontal_velocity_m_s << " m/s"
+                  << std::endl
+                  << "Vertical Velocity: " << adsbVehicle.vertical_velocity_m_s << " m/s"
+                  << std::endl
+                  << "Call Sign: " << adsbVehicle.callsign << std::endl
+                  << "Emitter Type: " << adsbVehicle.emitter_type << std::endl
+                  << "Squawk: " << adsbVehicle.squawk << std::endl
+                  << NORMAL_CONSOLE_TEXT // set to default color again
+                  << std::endl;
+    });
+
+    // Search for aircraft transponders
+    sleep_for(seconds(60));
+    std::cout << "Finished..." << std::endl;
+
+    return 0;
+}