Added radar

app/src/main/java/com/grigowashere/aismap/MainActivity.java

@@ -5,6 +5,7 @@ import android.content.Intent;
 import android.content.pm.PackageManager;
 import android.os.Bundle;
 import android.os.Looper;
+import android.os.SystemClock;
 import android.util.Log;
 import android.util.Printer;
 import android.view.Menu;
@@ -43,6 +44,7 @@ import com.grigowashere.aismap.view.BaseDockWidget;
 import com.grigowashere.aismap.ui.MenuBinder;
 import com.grigowashere.aismap.ui.BottomSheetsBinder;
 import com.grigowashere.aismap.ui.PermissionsBinder;
+import com.grigowashere.aismap.utils.AismapLocalHttpsProbe;
 import com.grigowashere.aismap.utils.SettingsManager;
 import com.grigowashere.aismap.utils.LogSender;
 import com.grigowashere.aismap.utils.MIDToCountry;
@@ -54,6 +56,9 @@ import org.maplibre.android.maps.MapView;
 import org.maplibre.android.MapLibre;
 import java.util.List;
 import java.util.ArrayList;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import com.grigowashere.aismap.controllers.ControllersFactory;
 import com.grigowashere.aismap.controllers.DefaultControllersFactory;
@@ -119,6 +124,12 @@ public class MainActivity extends AppCompatActivity {
     private TextView tvBleRssi;
     private TextView tvBleBatt;
     private TextView tvFps;
+    /** GET {@link AismapLocalHttpsProbe#PROBE_URL} on a worker; line shown under BLE RSSI. */
+    private ExecutorService localHttpsProbeExecutor;
+    private final AtomicBoolean localHttpsProbeInFlight = new AtomicBoolean(false);
+    private volatile String localHttpsProbeStatusLine = "HTTPS aismap.local: —";
+    private long nextLocalHttpsProbeElapsedMs = 0L;
+    private static final long LOCAL_HTTPS_PROBE_INTERVAL_MS = 12_000L;
     private int frameCount = 0;
     private long lastFpsTs = 0L;
     private final android.view.Choreographer.FrameCallback fpsCallback = new android.view.Choreographer.FrameCallback() {
@@ -487,6 +498,14 @@ public class MainActivity extends AppCompatActivity {
     }
 
     private void setupMessageAgesUpdater() {
+        if (localHttpsProbeExecutor == null) {
+            localHttpsProbeExecutor = Executors.newSingleThreadExecutor(r -> {
+                Thread t = new Thread(r, "aismap-local-https-probe");
+                t.setDaemon(true);
+                return t;
+            });
+            nextLocalHttpsProbeElapsedMs = 0L;
+        }
         messageAgeHandler = new android.os.Handler(android.os.Looper.getMainLooper());
         messageAgeRunnable = new Runnable() {
             @Override
@@ -506,13 +525,17 @@ public class MainActivity extends AppCompatActivity {
                         }
                         if (tvBleRssi != null) {
                             Integer rssi = appCoordinator.getLastBleRssi();
+                            String bleLine;
+                            int bleColor;
                             if (rssi != null) {
-                                tvBleRssi.setText("BLE RSSI: " + rssi);
+                                bleLine = "BLE RSSI: " + rssi;
-                                tvBleRssi.setTextColor(getRssiColor(rssi));
+                                bleColor = getRssiColor(rssi);
                             } else {
-                                tvBleRssi.setText("BLE RSSI: --");
+                                bleLine = "BLE RSSI: --";
-                                tvBleRssi.setTextColor(android.graphics.Color.parseColor("#F44336"));
+                                bleColor = android.graphics.Color.parseColor("#F44336");
                             }
+                            tvBleRssi.setText(bleLine + "\n" + localHttpsProbeStatusLine);
+                            tvBleRssi.setTextColor(bleColor);
                         }
                         if (tvBleBatt != null) {
                             Integer batt = appCoordinator.getLastBleBattery();
@@ -521,6 +544,11 @@ public class MainActivity extends AppCompatActivity {
                         updateBleLinkLostBanner();
                         updateDangerWidget();
                     }
+                    if (tvBleRssi != null && appCoordinator == null) {
+                        tvBleRssi.setText("BLE RSSI: --\n" + localHttpsProbeStatusLine);
+                        tvBleRssi.setTextColor(android.graphics.Color.parseColor("#F44336"));
+                    }
+                    triggerLocalHttpsProbeIfDue();
                 } catch (Exception ignored) {}
                 messageAgeHandler.postDelayed(this, 1000);
             }
@@ -529,6 +557,35 @@ public class MainActivity extends AppCompatActivity {
         messageAgeHandler.postDelayed(messageAgeRunnable, 1000);
     }
 
+    /**
+     * Throttled HTTPS GET to {@code aismap.local} on a worker; updates {@link #localHttpsProbeStatusLine}
+     * on the UI thread (shown with BLE RSSI).
+     */
+    private void triggerLocalHttpsProbeIfDue() {
+        if (localHttpsProbeInFlight.get()) return;
+        long now = SystemClock.elapsedRealtime();
+        if (now < nextLocalHttpsProbeElapsedMs) return;
+        ExecutorService ex = localHttpsProbeExecutor;
+        if (ex == null || ex.isShutdown()) return;
+        if (!localHttpsProbeInFlight.compareAndSet(false, true)) return;
+        nextLocalHttpsProbeElapsedMs = now + LOCAL_HTTPS_PROBE_INTERVAL_MS;
+        ex.execute(() -> {
+            try {
+                final String line = AismapLocalHttpsProbe.probeOnce();
+                runOnUiThread(() -> {
+                    localHttpsProbeStatusLine = line;
+                    localHttpsProbeInFlight.set(false);
+                });
+            } catch (Throwable t) {
+                Log.w(TAG, "local HTTPS probe worker", t);
+                runOnUiThread(() -> {
+                    localHttpsProbeStatusLine = "HTTPS aismap.local: " + t.getClass().getSimpleName();
+                    localHttpsProbeInFlight.set(false);
+                });
+            }
+        });
+    }
+
     /**
      * Баннер «нет связи с устройством» — только при потере BLE GATT-сессии с AIS Hub.
      * Возраст GPS/AIS здесь не используется: при обрыве линка данным доверять нельзя,
@@ -571,19 +628,20 @@ public class MainActivity extends AppCompatActivity {
     }
 
     /**
-     * Обновляет таблицу «Опасные цели» каждую секунду из AppCoordinator.
+     * Обновляет таблицу «Ближайшие цели» каждую секунду из AppCoordinator.
-     * Если опасных целей нет (или функция отключена в настройках) — виджет
+     * Цели берутся из жёлтой зоны предупреждения, а не из красного круга
-     * полностью скрывается, чтобы не занимать место на карте.
+     * опасности. Если целей нет (или кольца отключены) — виджет полностью
+     * скрывается, чтобы не занимать место на карте.
      */
     private void updateDangerWidget() {
         if (dangerWidget == null || appCoordinator == null || settingsManager == null) return;
         boolean enabled = settingsManager.isRangeRingsEnabled();
-        double dangerR = enabled ? settingsManager.getDangerRadiusMeters() : 0.0;
+        double nearestR = enabled ? settingsManager.getWarningRadiusMeters() : 0.0;
         java.util.List<com.grigowashere.aismap.view.DangerTargetsDockWidget.DangerEntry> uiEntries =
                 new java.util.ArrayList<>();
-        if (enabled && dangerR > 0.0) {
+        if (enabled && nearestR > 0.0) {
             java.util.List<com.grigowashere.aismap.controllers.AppCoordinator.DangerEntry> entries =
-                    appCoordinator.getDangerTargets(dangerR, 5);
+                    appCoordinator.getDangerTargets(nearestR, 5);
             if (entries != null) {
                 for (com.grigowashere.aismap.controllers.AppCoordinator.DangerEntry e : entries) {
                     if (e == null || e.vessel == null) continue;
@@ -592,7 +650,8 @@ public class MainActivity extends AppCompatActivity {
                         label = e.vessel.getMmsi() != null ? e.vessel.getMmsi() : "—";
                     }
                     uiEntries.add(new com.grigowashere.aismap.view.DangerTargetsDockWidget.DangerEntry(
-                            label, e.bearingDegrees, e.distanceMeters));
+                            label, e.bearingDegrees, e.distanceMeters,
+                            e.cpaValid, e.cpaMeters, e.tcpaMinutes));
                 }
             }
         }
@@ -1868,6 +1927,12 @@ public class MainActivity extends AppCompatActivity {
             messageAgeHandler.removeCallbacks(messageAgeRunnable);
             Log.i(TAG, "messageAgeHandler остановлен");
         }
+        if (localHttpsProbeExecutor != null) {
+            try {
+                localHttpsProbeExecutor.shutdownNow();
+            } catch (Throwable ignore) {}
+            localHttpsProbeExecutor = null;
+        }
         
         // Останавливаем UI watchdog
         if (uiWatchdogHandler != null && uiWatchdogRunnable != null) {

app/src/main/java/com/grigowashere/aismap/controllers/AppCoordinator.java

@@ -1265,11 +1265,24 @@ public class AppCoordinator implements
         public final double distanceMeters;
         /** Пеленг от собственного судна на цель, °. */
         public final double bearingDegrees;
+        /** CPA, м; {@link Double#NaN} если расчёт невозможен. */
+        public final double cpaMeters;
+        /** TCPA, мин; {@link Double#NaN} если расчёт невозможен. */
+        public final double tcpaMinutes;
+        public final boolean cpaValid;
 
         public DangerEntry(AISVessel vessel, double distanceMeters, double bearingDegrees) {
+            this(vessel, distanceMeters, bearingDegrees, false, Double.NaN, Double.NaN);
+        }
+
+        public DangerEntry(AISVessel vessel, double distanceMeters, double bearingDegrees,
+                           boolean cpaValid, double cpaMeters, double tcpaMinutes) {
             this.vessel = vessel;
             this.distanceMeters = distanceMeters;
             this.bearingDegrees = bearingDegrees;
+            this.cpaValid = cpaValid;
+            this.cpaMeters = cpaMeters;
+            this.tcpaMinutes = tcpaMinutes;
         }
     }
 
@@ -1288,6 +1301,9 @@ public class AppCoordinator implements
         double oLat = ownVessel.getLatitude();
         double oLon = ownVessel.getLongitude();
         if (!com.grigowashere.aismap.utils.GeoUtils.isValidCoordinates(oLat, oLon)) return result;
+        double ownSog = ownVessel.getSpeed();
+        double ownCog = ownVessel.getCourse();
+        double ownHdg = ownVessel.getHeading();
 
         synchronized (aisVessels) {
             for (AISVessel vessel : aisVessels.values()) {
@@ -1298,10 +1314,18 @@ public class AppCoordinator implements
                 double d = com.grigowashere.aismap.utils.GeoUtils.calculateDistance(oLat, oLon, lat, lon);
                 if (d <= maxRadiusMeters) {
                     double b = com.grigowashere.aismap.utils.GeoUtils.calculateBearing(oLat, oLon, lat, lon);
+                    com.grigowashere.aismap.utils.RangeMath.CpaResult cpa =
+                            com.grigowashere.aismap.utils.RangeMath.calculateCpa(
+                                    oLat, oLon, ownSog, ownCog, ownHdg,
+                                    lat, lon, vessel.getSpeed(), vessel.getCourse(), vessel.getHeading());
+                    if (cpa.valid) {
+                        result.add(new DangerEntry(vessel, d, b, true, cpa.cpaMeters, cpa.tcpaMinutes));
+                    } else {
                         result.add(new DangerEntry(vessel, d, b));
                     }
                 }
             }
+        }
         java.util.Collections.sort(result, (a, b) -> Double.compare(a.distanceMeters, b.distanceMeters));
         if (limit > 0 && result.size() > limit) {
             return new ArrayList<>(result.subList(0, limit));

app/src/main/java/com/grigowashere/aismap/maps/MapLibreMapImpl.java

@@ -649,6 +649,11 @@ public class MapLibreMapImpl implements MapInterface {
                 } catch (Exception ignore) {}
 
                 idToFeature.put(vessel.getMmsi(), feature);
+                if (PATH_FEATURES_ENABLED) {
+                    String mmsi = vessel.getMmsi();
+                    updateAISPathSource(mmsi);
+                    updateAISVesselPredictionSource(mmsi, vessel);
+                }
                 updated++;
             }
 
@@ -2456,6 +2461,9 @@ public class MapLibreMapImpl implements MapInterface {
                     // Обновляем путь этого AIS судна
                     updateAISVesselPath(mmsi, aisPathController);
                 }
+                if (PATH_FEATURES_ENABLED) {
+                    updateAISVesselPredictionSource(mmsi, vessel);
+                }
             }
         } catch (Exception e) {
             Log.e(TAG, "Ошибка обновления путей AIS судов: " + e.getMessage(), e);

app/src/main/java/com/grigowashere/aismap/maps/RadarMapHelper.java

@@ -1,7 +1,11 @@
 package com.grigowashere.aismap.maps;
 
+import android.os.Handler;
+import android.os.Looper;
 import android.util.Log;
 
+import com.grigowashere.aismap.utils.NavigatorZoomMath;
+
 import org.maplibre.android.camera.CameraPosition;
 import org.maplibre.android.camera.CameraUpdateFactory;
 import org.maplibre.android.geometry.LatLng;
@@ -17,10 +21,24 @@ public class RadarMapHelper {
     private static final String TAG = "RadarMapHelper";
     private static final String STYLE_URL =
             "https://basemaps.cartocdn.com/gl/positron-gl-style/style.json";
+    private static final long FRAME_MS = 16L;
+    private static final float POSITION_ALPHA = 0.20f;
+    private static final float ZOOM_ALPHA = 0.14f;
+    /** Как в {@link com.grigowashere.aismap.controllers.NavigatorCameraController}. */
+    private static final float BEARING_ALPHA = 0.09f;
 
     private final MapView mapView;
+    private final Handler handler = new Handler(Looper.getMainLooper());
     private MapLibreMap map;
     private boolean styleLoaded;
+    private boolean followLoopRunning;
+
+    private double targetLat = Double.NaN;
+    private double targetLon = Double.NaN;
+    private float targetBearing;
+    private double targetRangeMeters = 1000.0;
+
+    private final Runnable followLoopRunnable = this::onFollowFrame;
 
     public RadarMapHelper(MapView mapView) {
         this.mapView = mapView;
@@ -58,6 +76,7 @@ public class RadarMapHelper {
     }
 
     public void onPause() {
+        stopFollowLoop();
         mapView.onPause();
     }
 
@@ -66,6 +85,7 @@ public class RadarMapHelper {
     }
 
     public void onDestroy() {
+        stopFollowLoop();
         mapView.onDestroy();
     }
 
@@ -79,20 +99,64 @@ public class RadarMapHelper {
 
     /**
      * Центрирует карту на собственном судне; bearing задаёт режим «курс вверх».
+     * Поворот и смещение камеры сглаживаются так же, как в режиме навигатора.
      *
      * @param rangeMeters радиус PPI для подбора зума
      */
     public void centerOnOwnShip(double lat, double lon, float bearingDeg, double rangeMeters) {
         if (map == null || !styleLoaded) return;
         if (Double.isNaN(lat) || Double.isNaN(lon)) return;
-        double zoom = zoomForRangeMeters(rangeMeters);
+        targetLat = lat;
+        targetLon = lon;
+        targetBearing = bearingDeg;
+        if (rangeMeters > 0.0) {
+            targetRangeMeters = rangeMeters;
+        }
+        startFollowLoop();
+    }
+
+    private void startFollowLoop() {
+        if (followLoopRunning) return;
+        followLoopRunning = true;
+        handler.removeCallbacks(followLoopRunnable);
+        handler.post(followLoopRunnable);
+    }
+
+    private void stopFollowLoop() {
+        followLoopRunning = false;
+        handler.removeCallbacks(followLoopRunnable);
+    }
+
+    private void onFollowFrame() {
+        if (!followLoopRunning || map == null || !styleLoaded || Double.isNaN(targetLat)) {
+            followLoopRunning = false;
+            return;
+        }
+
+        try {
+            CameraPosition current = map.getCameraPosition();
+            double curLat = current.target.getLatitude();
+            double curLon = current.target.getLongitude();
+            float curBearing = (float) current.bearing;
+            double targetZoom = zoomForRangeMeters(targetRangeMeters);
+
+            double newLat = NavigatorZoomMath.lerp(curLat, targetLat, POSITION_ALPHA);
+            double newLon = NavigatorZoomMath.lerp(curLon, targetLon, POSITION_ALPHA);
+            float newBearing = NavigatorZoomMath.lerpBearing(curBearing, targetBearing, BEARING_ALPHA);
+            double newZoom = NavigatorZoomMath.lerp(current.zoom, targetZoom, ZOOM_ALPHA);
+
             CameraPosition position = new CameraPosition.Builder()
-                .target(new LatLng(lat, lon))
+                    .target(new LatLng(newLat, newLon))
-                .zoom(zoom)
+                    .zoom(newZoom)
-                .bearing(bearingDeg)
+                    .bearing(newBearing)
                     .tilt(0.0)
                     .build();
-        map.easeCamera(CameraUpdateFactory.newCameraPosition(position), 400);
+            map.moveCamera(CameraUpdateFactory.newCameraPosition(position));
+        } catch (Exception e) {
+            Log.w(TAG, "onFollowFrame: " + e.getMessage());
+        }
+
+        handler.postDelayed(followLoopRunnable, FRAME_MS);
     }
 
     /** Подбирает зум так, чтобы весь радиус PPI помещался в круговой области. */

app/src/main/java/com/grigowashere/aismap/ui/BottomSheetsManager.java

@@ -191,6 +191,7 @@ public class BottomSheetsManager {
         TextView tvSignal = aisBottomSheetView.findViewById(R.id.bottom_sheet_ais_signal);
         TextView tvDistance = aisBottomSheetView.findViewById(R.id.bottom_sheet_ais_distance);
         TextView tvBearing = aisBottomSheetView.findViewById(R.id.bottom_sheet_ais_bearing);
+        TextView tvCpa = aisBottomSheetView.findViewById(R.id.bottom_sheet_ais_cpa);
         TextView tvLastUpdate = aisBottomSheetView.findViewById(R.id.bottom_sheet_ais_last_update);
         TextView tvTimeAgo = aisBottomSheetView.findViewById(R.id.bottom_sheet_ais_time_ago);
 
@@ -233,17 +234,52 @@ public class BottomSheetsManager {
         }
         if (tvLastUpdate != null) tvLastUpdate.setText(vessel.getLastUpdate() != null ? String.format("Обновлено: %s", vessel.getLastUpdate().format(java.time.format.DateTimeFormatter.ofPattern("dd.MM.yyyy HH:mm:ss"))) : "Обновлено: --");
 
-        if (tvDistance != null || tvBearing != null) {
+        if (tvDistance != null || tvBearing != null || tvCpa != null) {
             Vessel ourVessel = appCoordinator.getOwnVessel();
-            if (ourVessel != null && ourVessel.getLatitude() != 0 && ourVessel.getLongitude() != 0 && vessel.getLatitude() != 0 && vessel.getLongitude() != 0) {
+            String cpaNa = context.getString(R.string.cpa_na);
-                double distance = com.grigowashere.aismap.utils.NavigationUtils.calculateDistance(ourVessel.getLatitude(), ourVessel.getLongitude(), vessel.getLatitude(), vessel.getLongitude());
+            if (ourVessel != null && ourVessel.getLatitude() != 0 && ourVessel.getLongitude() != 0
-                if (tvDistance != null) tvDistance.setText("Расстояние: " + com.grigowashere.aismap.utils.NavigationUtils.formatDistance(distance));
+                    && vessel.getLatitude() != 0 && vessel.getLongitude() != 0) {
-                double bearing = com.grigowashere.aismap.utils.NavigationUtils.calculateBearing(ourVessel.getLatitude(), ourVessel.getLongitude(), vessel.getLatitude(), vessel.getLongitude());
+                double distance = com.grigowashere.aismap.utils.NavigationUtils.calculateDistance(
-                double relativeBearing = com.grigowashere.aismap.utils.NavigationUtils.calculateRelativeBearing(ourVessel.getCourse(), bearing);
+                        ourVessel.getLatitude(), ourVessel.getLongitude(),
-                if (tvBearing != null) tvBearing.setText("Пеленг: " + com.grigowashere.aismap.utils.NavigationUtils.formatRelativeBearing(relativeBearing));
+                        vessel.getLatitude(), vessel.getLongitude());
+                if (tvDistance != null) {
+                    tvDistance.setText("Расстояние: "
+                            + com.grigowashere.aismap.utils.NavigationUtils.formatDistance(distance));
+                }
+                double bearing = com.grigowashere.aismap.utils.NavigationUtils.calculateBearing(
+                        ourVessel.getLatitude(), ourVessel.getLongitude(),
+                        vessel.getLatitude(), vessel.getLongitude());
+                double relativeBearing = com.grigowashere.aismap.utils.NavigationUtils.calculateRelativeBearing(
+                        ourVessel.getCourse(), bearing);
+                if (tvBearing != null) {
+                    tvBearing.setText("Пеленг: "
+                            + com.grigowashere.aismap.utils.NavigationUtils.formatRelativeBearing(relativeBearing));
+                }
+                if (tvCpa != null) {
+                    com.grigowashere.aismap.utils.SettingsManager sm =
+                            new com.grigowashere.aismap.utils.SettingsManager(context);
+                    boolean useNm = com.grigowashere.aismap.utils.SettingsManager.RANGE_UNIT_NM
+                            .equals(sm.getRangeUnit());
+                    com.grigowashere.aismap.utils.RangeMath.CpaResult cpa =
+                            com.grigowashere.aismap.utils.RangeMath.calculateCpa(
+                                    ourVessel.getLatitude(), ourVessel.getLongitude(),
+                                    ourVessel.getSpeed(), ourVessel.getCourse(), ourVessel.getHeading(),
+                                    vessel.getLatitude(), vessel.getLongitude(),
+                                    vessel.getSpeed(), vessel.getCourse(), vessel.getHeading());
+                    if (cpa.valid) {
+                        String cpaDist = com.grigowashere.aismap.utils.RangeMath.formatCpaDistance(
+                                cpa.cpaMeters, useNm, java.util.Locale.getDefault());
+                        String tcpa = com.grigowashere.aismap.utils.RangeMath.formatTcpa(
+                                cpa.tcpaMinutes, java.util.Locale.getDefault());
+                        tvCpa.setText(context.getString(R.string.bottom_sheet_ais_cpa, cpaDist, tcpa));
+                    } else {
+                        tvCpa.setText(context.getString(R.string.bottom_sheet_ais_cpa, cpaNa, cpaNa));
+                    }
+                }
             } else {
                 if (tvDistance != null) tvDistance.setText("Расстояние: --");
                 if (tvBearing != null) tvBearing.setText("Пеленг: --");
+                if (tvCpa != null) tvCpa.setText(context.getString(R.string.bottom_sheet_ais_cpa, cpaNa, cpaNa));
             }
         }
 

app/src/main/java/com/grigowashere/aismap/utils/AismapLocalHttpsProbe.java

@@ -0,0 +1,110 @@
+package com.grigowashere.aismap.utils;
+
+import android.util.Log;
+
+import java.io.InputStream;
+import java.net.ConnectException;
+import java.net.HttpURLConnection;
+import java.net.NoRouteToHostException;
+import java.net.SocketTimeoutException;
+import java.net.URL;
+import java.net.UnknownHostException;
+import java.security.cert.CertificateException;
+import java.util.Locale;
+
+import javax.net.ssl.SSLException;
+import javax.net.ssl.SSLHandshakeException;
+import javax.net.ssl.SSLPeerUnverifiedException;
+
+/**
+ * Lightweight reachability check for {@code https://aismap.local/} (feasibility / diagnostics).
+ * Runs on a background thread; callers must not invoke from the UI thread.
+ */
+public final class AismapLocalHttpsProbe {
+
+    private static final String TAG = "AismapLocalHttpsProbe";
+
+    /** Hub HTTPS root — user-requested feasibility target. */
+    public static final String PROBE_URL = "https://aismap.local/";
+
+    private static final int CONNECT_TIMEOUT_MS = 2500;
+    private static final int READ_TIMEOUT_MS = 2500;
+
+    private AismapLocalHttpsProbe() {}
+
+    /**
+     * Performs a GET with short timeouts. Returns a short UI-safe line (no stack traces).
+     */
+    public static String probeOnce() {
+        HttpURLConnection conn = null;
+        try {
+            URL url = new URL(PROBE_URL);
+            conn = (HttpURLConnection) url.openConnection();
+            conn.setConnectTimeout(CONNECT_TIMEOUT_MS);
+            conn.setReadTimeout(READ_TIMEOUT_MS);
+            conn.setRequestMethod("GET");
+            conn.setInstanceFollowRedirects(true);
+            conn.setUseCaches(false);
+            int code = conn.getResponseCode();
+            InputStream body = code >= HttpURLConnection.HTTP_BAD_REQUEST
+                    ? conn.getErrorStream() : conn.getInputStream();
+            drain(body);
+            if (code >= 200 && code < 400) {
+                return "HTTPS aismap.local: OK HTTP " + code;
+            }
+            return "HTTPS aismap.local: HTTP " + code;
+        } catch (Throwable t) {
+            Log.w(TAG, "probe failed: " + t.getClass().getSimpleName() + ": " + t.getMessage(), t);
+            return "HTTPS aismap.local: " + classify(t);
+        } finally {
+            if (conn != null) {
+                try {
+                    conn.disconnect();
+                } catch (Throwable ignore) {}
+            }
+        }
+    }
+
+    private static void drain(InputStream in) {
+        if (in == null) return;
+        byte[] buf = new byte[512];
+        try (InputStream stream = in) {
+            while (stream.read(buf) != -1) { /* discard */ }
+        } catch (Throwable ignore) {}
+    }
+
+    static String classify(Throwable t) {
+        if (t instanceof SSLHandshakeException || t instanceof SSLPeerUnverifiedException) {
+            return "TLS/cert issue";
+        }
+        if (t instanceof CertificateException) {
+            return "TLS/cert issue";
+        }
+        if (t instanceof SSLException) {
+            String m = t.getMessage();
+            if (m != null && m.toLowerCase(Locale.US).contains("cert")) {
+                return "TLS/cert issue";
+            }
+            return "TLS: " + t.getClass().getSimpleName();
+        }
+        if (t instanceof SocketTimeoutException) {
+            return "timeout";
+        }
+        if (t instanceof UnknownHostException) {
+            return "no DNS (aismap.local)";
+        }
+        if (t instanceof ConnectException || t instanceof NoRouteToHostException) {
+            return "no route / refused";
+        }
+        Throwable c = t.getCause();
+        if (c != null && c != t) {
+            return classify(c);
+        }
+        String m = t.getMessage();
+        if (m != null && !m.isEmpty()) {
+            String shortM = m.length() > 48 ? m.substring(0, 45) + "…" : m;
+            return t.getClass().getSimpleName() + ": " + shortM;
+        }
+        return t.getClass().getSimpleName();
+    }
+}

app/src/main/java/com/grigowashere/aismap/utils/RangeMath.java

@@ -69,4 +69,159 @@ public final class RangeMath {
         double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
         return R * c;
     }
+
+    /** AIS SOG «not available» (102.3 kn). */
+    public static final double AIS_SOG_NOT_AVAILABLE = 102.3;
+    /** AIS COG «not available» (360°). */
+    public static final double AIS_COG_NOT_AVAILABLE = 360.0;
+    /** AIS HDG «not available» (511°). */
+    public static final double AIS_HDG_NOT_AVAILABLE = 511.0;
+
+    /** Минимальная относительная скорость (м/с) для расчёта TCPA. */
+    private static final double MIN_REL_SPEED_MS = 0.02;
+
+    /**
+     * Результат расчёта CPA/TCPA.
+     * <p>{@link #tcpaMinutes} отрицательный — CPA уже пройден или сближение невозможно.
+     */
+    public static final class CpaResult {
+        public final boolean valid;
+        /** Минимальная дистанция сближения, м. */
+        public final double cpaMeters;
+        /** Время до CPA, мин (отрицательное — в прошлом / расхождение). */
+        public final double tcpaMinutes;
+
+        public CpaResult(boolean valid, double cpaMeters, double tcpaMinutes) {
+            this.valid = valid;
+            this.cpaMeters = cpaMeters;
+            this.tcpaMinutes = tcpaMinutes;
+        }
+
+        public static final CpaResult INVALID = new CpaResult(false, Double.NaN, Double.NaN);
+    }
+
+    public static boolean isValidAisSpeed(double sogKn) {
+        if (Double.isNaN(sogKn) || Double.isInfinite(sogKn)) return false;
+        return sogKn >= 0.0 && sogKn < AIS_SOG_NOT_AVAILABLE;
+    }
+
+    public static boolean isValidAisCourse(double cogDeg) {
+        if (Double.isNaN(cogDeg) || Double.isInfinite(cogDeg)) return false;
+        return cogDeg >= 0.0 && cogDeg < AIS_COG_NOT_AVAILABLE;
+    }
+
+    public static boolean isValidAisHeading(double hdgDeg) {
+        if (Double.isNaN(hdgDeg) || Double.isInfinite(hdgDeg)) return false;
+        int h = (int) Math.round(hdgDeg);
+        if (h == (int) AIS_HDG_NOT_AVAILABLE) return false;
+        return h >= 0 && h <= 359;
+    }
+
+    /**
+     * Курс для вектора движения: валидный HDG, иначе COG.
+     */
+    public static double resolveMotionCourse(double cogDeg, double headingDeg) {
+        if (isValidAisHeading(headingDeg)) {
+            return normalizeCourse360(headingDeg);
+        }
+        if (isValidAisCourse(cogDeg)) {
+            return normalizeCourse360(cogDeg);
+        }
+        return Double.NaN;
+    }
+
+    public static double normalizeCourse360(double courseDeg) {
+        if (Double.isNaN(courseDeg) || Double.isInfinite(courseDeg)) return Double.NaN;
+        double c = courseDeg % 360.0;
+        if (c < 0) c += 360.0;
+        return c;
+    }
+
+    public static double knotsToMetersPerSecond(double knots) {
+        return knots * METERS_PER_NM / 3600.0;
+    }
+
+    /**
+     * CPA/TCPA в локальной плоскости (север/восток), стандартный относительный вектор.
+     */
+    public static CpaResult calculateCpa(double ownLat, double ownLon,
+                                         double ownSogKn, double ownCogDeg, double ownHdgDeg,
+                                         double tgtLat, double tgtLon,
+                                         double tgtSogKn, double tgtCogDeg, double tgtHdgDeg) {
+        if (Double.isNaN(ownLat) || Double.isNaN(ownLon)
+                || Double.isNaN(tgtLat) || Double.isNaN(tgtLon)) {
+            return CpaResult.INVALID;
+        }
+        if (!isValidAisSpeed(ownSogKn) || !isValidAisSpeed(tgtSogKn)) {
+            return CpaResult.INVALID;
+        }
+        double ownCourse = resolveMotionCourse(ownCogDeg, ownHdgDeg);
+        double tgtCourse = resolveMotionCourse(tgtCogDeg, tgtHdgDeg);
+        if (Double.isNaN(ownCourse) || Double.isNaN(tgtCourse)) {
+            return CpaResult.INVALID;
+        }
+
+        double[] pr = relativePositionNeMeters(ownLat, ownLon, tgtLat, tgtLon);
+        double[] vo = velocityNeMetersPerSecond(ownSogKn, ownCourse);
+        double[] vt = velocityNeMetersPerSecond(tgtSogKn, tgtCourse);
+        double vrN = vt[0] - vo[0];
+        double vrE = vt[1] - vo[1];
+        double vr2 = vrN * vrN + vrE * vrE;
+        if (vr2 < MIN_REL_SPEED_MS * MIN_REL_SPEED_MS) {
+            return CpaResult.INVALID;
+        }
+        double dot = pr[0] * vrN + pr[1] * vrE;
+        double tcpaSec = -dot / vr2;
+        double cpaN = pr[0] + vrN * tcpaSec;
+        double cpaE = pr[1] + vrE * tcpaSec;
+        double cpaMeters = Math.hypot(cpaN, cpaE);
+        double tcpaMinutes = tcpaSec / 60.0;
+        return new CpaResult(true, cpaMeters, tcpaMinutes);
+    }
+
+    /** NE-смещение цели относительно своего судна, м (север, восток). */
+    static double[] relativePositionNeMeters(double ownLat, double ownLon,
+                                             double tgtLat, double tgtLon) {
+        double latMidRad = Math.toRadians((ownLat + tgtLat) * 0.5);
+        double mPerDegLat = 111_320.0;
+        double mPerDegLon = 111_320.0 * Math.cos(latMidRad);
+        double north = (tgtLat - ownLat) * mPerDegLat;
+        double east = (tgtLon - ownLon) * mPerDegLon;
+        return new double[] { north, east };
+    }
+
+    /** Скорость по курсу (0° = север), м/с. */
+    static double[] velocityNeMetersPerSecond(double sogKn, double cogDeg) {
+        double speedMs = knotsToMetersPerSecond(sogKn);
+        double rad = Math.toRadians(cogDeg);
+        return new double[] {
+                speedMs * Math.cos(rad),
+                speedMs * Math.sin(rad)
+        };
+    }
+
+    /** Краткая строка CPA + TCPA для таблиц (nm/km + мин). */
+    public static String formatCpaTcpaShort(CpaResult result, boolean useNm,
+                                            String na, java.util.Locale locale) {
+        if (result == null || !result.valid) return na;
+        return formatCpaDistance(result.cpaMeters, useNm, locale)
+                + " " + formatTcpa(result.tcpaMinutes, locale);
+    }
+
+    public static String formatCpaDistance(double meters, boolean useNm, java.util.Locale locale) {
+        if (useNm) {
+            return String.format(locale, "%.2f nm", meters / METERS_PER_NM);
+        }
+        if (meters >= 1000.0) {
+            return String.format(locale, "%.2f km", meters / METERS_PER_KM);
+        }
+        return String.format(locale, "%.0f m", meters);
+    }
+
+    public static String formatTcpa(double tcpaMinutes, java.util.Locale locale) {
+        if (tcpaMinutes >= 0.0) {
+            return String.format(locale, "+%.0f мин", tcpaMinutes);
+        }
+        return String.format(locale, "%.0f мин", tcpaMinutes);
+    }
 }

app/src/main/java/com/grigowashere/aismap/view/DangerTargetsDockWidget.java

@@ -9,6 +9,7 @@ import android.util.AttributeSet;
 
 import com.grigowashere.aismap.R;
 import com.grigowashere.aismap.controllers.AppCoordinator;
+import com.grigowashere.aismap.utils.RangeMath;
 import com.grigowashere.aismap.utils.SettingsManager;
 
 import java.util.ArrayList;
@@ -17,10 +18,12 @@ import java.util.List;
 import java.util.Locale;
 
 /**
- * Виджет «Опасные цели» — таблица ближайших AIS-целей в зоне опасности.
+ * Виджет «Ближайшие цели» — таблица AIS-целей в радиусе жёлтого кольца
- * Колонки: имя/MMSI, пеленг (°), дистанция (nm/km — в зависимости от настроек).
+ * предупреждения. Колонки: имя/MMSI, пеленг (°), дистанция (nm/km — в
+ * зависимости от настроек).
  * <p>Обновление выполняется через {@link #setEntries(List)} с частотой 1 Hz из
- * MainActivity, источник данных — {@link AppCoordinator#getDangerTargets(double, int)}.
+ * MainActivity, источник данных — {@link AppCoordinator#getDangerTargets(double, int)}
+ * с радиусом {@link SettingsManager#getWarningRadiusMeters()}.
  */
 public class DangerTargetsDockWidget extends BaseDockWidget {
 
@@ -29,11 +32,22 @@ public class DangerTargetsDockWidget extends BaseDockWidget {
         public final String name;
         public final double bearingDeg;
         public final double distanceMeters;
+        public final boolean cpaValid;
+        public final double cpaMeters;
+        public final double tcpaMinutes;
 
         public DangerEntry(String name, double bearingDeg, double distanceMeters) {
+            this(name, bearingDeg, distanceMeters, false, Double.NaN, Double.NaN);
+        }
+
+        public DangerEntry(String name, double bearingDeg, double distanceMeters,
+                           boolean cpaValid, double cpaMeters, double tcpaMinutes) {
             this.name = name;
             this.bearingDeg = bearingDeg;
             this.distanceMeters = distanceMeters;
+            this.cpaValid = cpaValid;
+            this.cpaMeters = cpaMeters;
+            this.tcpaMinutes = tcpaMinutes;
         }
     }
 
@@ -49,7 +63,7 @@ public class DangerTargetsDockWidget extends BaseDockWidget {
     private static final int BACKGROUND_COLOR = 0xD92A1A1A;
     private static final int LABEL_COLOR = 0xFFE0B0B0;
     private static final int TEXT_COLOR = 0xFFFFFFFF;
-    private static final int ACCENT_COLOR = 0xFFFF6B6B;
+    private static final int ACCENT_COLOR = 0xFFFFA000;
 
     private Paint backgroundPaint;
     private Paint titlePaint;
@@ -78,7 +92,7 @@ public class DangerTargetsDockWidget extends BaseDockWidget {
 
     @Override
     protected boolean getDefaultDockTop() {
-        // Виджет «Опасные цели» по умолчанию сидит ВНИЗУ над координатами —
+        // Виджет «Ближайшие цели» по умолчанию сидит ВНИЗУ над координатами —
         // это самая безболезненная для карты позиция: при отсутствии целей
         // он вообще скрыт, а когда появляется, не разрывает обзор по центру.
         return false;
@@ -217,7 +231,7 @@ public class DangerTargetsDockWidget extends BaseDockWidget {
             snapshot = new ArrayList<>(entries);
         }
 
-        // === Заголовок: «Опасные цели · N» ===
+        // === Заголовок: «Ближайшие цели · N» ===
         float titleBaseline = top + dp(4) + titlePaint.getTextSize();
         String titleBase = getResources().getString(R.string.danger_widget_title);
         String title = snapshot.isEmpty()
@@ -233,14 +247,15 @@ public class DangerTargetsDockWidget extends BaseDockWidget {
             return;
         }
 
-        // === Строки целей. Колонки: имя | пеленг | дистанция ===
+        // === Строки целей. Колонки: имя | пеленг | дистанция | CPA ===
-        // Имя — широкая колонка слева, пеленг и дистанция — справа выровнены по
+        String cpaNa = getResources().getString(R.string.cpa_na);
-        // фиксированной ширине, чтобы цифры не «прыгали» между строками.
+        float cpaMaxWidth = accentPaint.measureText("9.99 nm +99 мин");
         float distMaxWidth = textPaint.measureText("999.99 nm");
         float bearingMaxWidth = textPaint.measureText("000\u00B0");
-        float colDistanceRight = innerRight;
+        float colCpaRight = innerRight;
-        float colBearingRight = colDistanceRight - distMaxWidth - dp(10);
+        float colDistanceRight = colCpaRight - cpaMaxWidth - dp(6);
-        float nameRight = colBearingRight - bearingMaxWidth - dp(10);
+        float colBearingRight = colDistanceRight - distMaxWidth - dp(6);
+        float nameRight = colBearingRight - bearingMaxWidth - dp(6);
 
         boolean useNm = settingsManager == null
                 || SettingsManager.RANGE_UNIT_NM.equals(settingsManager.getRangeUnit());
@@ -254,13 +269,21 @@ public class DangerTargetsDockWidget extends BaseDockWidget {
             String name = ellipsize(rawName, textPaint, nameRight - innerLeft - dp(4));
             String bearing = String.format(Locale.US, "%03.0f\u00B0", e.bearingDeg);
             String distance = formatDistance(e.distanceMeters, useNm);
+            String cpa;
+            if (e.cpaValid) {
+                cpa = RangeMath.formatCpaDistance(e.cpaMeters, useNm, Locale.US)
+                        + " " + RangeMath.formatTcpa(e.tcpaMinutes, Locale.US);
+            } else {
+                cpa = cpaNa;
+            }
 
             canvas.drawText(name, innerLeft, y, textPaint);
-            // Пеленг и дистанция — выравнивание справа по своим колонкам.
             float bearingWidth = textPaint.measureText(bearing);
             canvas.drawText(bearing, colBearingRight - bearingWidth, y, textPaint);
-            float distanceWidth = accentPaint.measureText(distance);
+            float distanceWidth = textPaint.measureText(distance);
-            canvas.drawText(distance, colDistanceRight - distanceWidth, y, accentPaint);
+            canvas.drawText(distance, colDistanceRight - distanceWidth, y, textPaint);
+            float cpaWidth = accentPaint.measureText(cpa);
+            canvas.drawText(cpa, colCpaRight - cpaWidth, y, accentPaint);
 
             y += rowH;
         }
@@ -310,8 +333,13 @@ public class DangerTargetsDockWidget extends BaseDockWidget {
                 centerY - dp(28), subPaint);
 
         if (nearest != null) {
-            String nearestStr = String.format(Locale.US, "%03.0f\u00B0  %s",
+            String cpaPart = nearest.cpaValid
-                    nearest.bearingDeg, formatDistance(nearest.distanceMeters, useNm));
+                    ? RangeMath.formatCpaTcpaShort(
+                            new RangeMath.CpaResult(true, nearest.cpaMeters, nearest.tcpaMinutes),
+                            useNm, getResources().getString(R.string.cpa_na), Locale.US)
+                    : getResources().getString(R.string.cpa_na);
+            String nearestStr = String.format(Locale.US, "%03.0f\u00B0  %s  %s",
+                    nearest.bearingDeg, formatDistance(nearest.distanceMeters, useNm), cpaPart);
             b = new Rect();
             subPaint.getTextBounds(nearestStr, 0, nearestStr.length(), b);
             canvas.drawText(nearestStr, centerX - b.width() / 2f - b.left,

app/src/main/java/com/grigowashere/aismap/view/PlotterTargetsTableView.java

@@ -12,6 +12,7 @@ import androidx.core.content.ContextCompat;
 
 import com.grigowashere.aismap.R;
 import com.grigowashere.aismap.controllers.AppCoordinator;
+import com.grigowashere.aismap.utils.RangeMath;
 import com.grigowashere.aismap.utils.SettingsManager;
 
 import java.util.ArrayList;
@@ -28,11 +29,22 @@ public class PlotterTargetsTableView extends View {
         public final String name;
         public final double bearingDeg;
         public final double distanceMeters;
+        public final boolean cpaValid;
+        public final double cpaMeters;
+        public final double tcpaMinutes;
 
         public Row(String name, double bearingDeg, double distanceMeters) {
+            this(name, bearingDeg, distanceMeters, false, Double.NaN, Double.NaN);
+        }
+
+        public Row(String name, double bearingDeg, double distanceMeters,
+                   boolean cpaValid, double cpaMeters, double tcpaMinutes) {
             this.name = name;
             this.bearingDeg = bearingDeg;
             this.distanceMeters = distanceMeters;
+            this.cpaValid = cpaValid;
+            this.cpaMeters = cpaMeters;
+            this.tcpaMinutes = tcpaMinutes;
         }
     }
 
@@ -100,7 +112,8 @@ public class PlotterTargetsTableView extends View {
                 if (label == null || label.trim().isEmpty()) {
                     label = e.vessel.getMmsi() != null ? e.vessel.getMmsi() : "—";
                 }
-                next.add(new Row(label, e.bearingDegrees, e.distanceMeters));
+                next.add(new Row(label, e.bearingDegrees, e.distanceMeters,
+                        e.cpaValid, e.cpaMeters, e.tcpaMinutes));
                 if (next.size() >= MAX_ROWS) break;
             }
         }
@@ -156,7 +169,13 @@ public class PlotterTargetsTableView extends View {
             canvas.drawText(name, colName, y, rowPaint);
             canvas.drawText(String.format(Locale.US, "%03.0f\u00B0", r.bearingDeg), colBrg, y, rowPaint);
             canvas.drawText(formatDistance(r.distanceMeters, useNm), colRng, y, rowPaint);
-            canvas.drawText(cpaNa, colCpa, y, accentPaint);
+            String cpaText;
+            if (r.cpaValid) {
+                cpaText = RangeMath.formatCpaDistance(r.cpaMeters, useNm, Locale.US);
+            } else {
+                cpaText = cpaNa;
+            }
+            canvas.drawText(cpaText, colCpa, y, accentPaint);
             y += rowH;
             if (y > h - pad) break;
         }

app/src/main/res/layout/activity_main.xml

@@ -199,6 +199,7 @@
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_marginTop="2dp"
+            android:maxLines="8"
             android:text="BLE RSSI: --"
             android:textColor="@android:color/white"
             android:textSize="10sp" />

app/src/main/res/layout/bottom_sheet_ais_vessel.xml

@@ -285,6 +285,18 @@
                 android:background="@android:color/transparent"
                 android:padding="8dp" />
 
+            <!-- CPA / TCPA -->
+            <TextView
+                android:id="@+id/bottom_sheet_ais_cpa"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:text="CPA: —, TCPA: —"
+                android:textSize="14sp"
+                android:textColor="@android:color/black"
+                android:layout_marginBottom="8dp"
+                android:background="@android:color/transparent"
+                android:padding="8dp" />
+
             <!-- Последнее обновление -->
             <TextView
                 android:id="@+id/bottom_sheet_ais_last_update"

app/src/main/res/values/strings.xml

@@ -35,7 +35,7 @@
     <string name="settings_range_unit_nm">Морские мили (nm)</string>
     <string name="settings_range_unit_km">Километры (км)</string>
     <string name="settings_range_danger_hint">Радиус зоны опасности</string>
-    <string name="settings_range_danger_helper">Цели в этой зоне отображаются в виджете и считаются опасными</string>
+    <string name="settings_range_danger_helper">Красное кольцо опасности на карте</string>
     <string name="settings_range_warning_hint">Радиус зоны предупреждения</string>
     <string name="settings_range_warning_helper">Цели в этой зоне подсвечиваются на карте</string>
     <string name="settings_range_filter_hint">Радиус зоны фильтра</string>
@@ -131,11 +131,13 @@
     <string name="banner_pairing_required">BLE требует сопряжения. Проверьте устройство в настройках Bluetooth.</string>
     <string name="banner_icon_description">Иконка предупреждения связи</string>
 
-    <string name="danger_widget_title">Опасные цели</string>
+    <string name="danger_widget_title">Ближайшие цели</string>
-    <string name="danger_widget_empty">В зоне опасности нет целей</string>
+    <string name="danger_widget_empty">Ближайших целей нет</string>
     <string name="danger_widget_column_target">Цель</string>
     <string name="danger_widget_column_bearing">Пел.</string>
     <string name="danger_widget_column_distance">Дист.</string>
+    <string name="cpa_na">—</string>
+    <string name="bottom_sheet_ais_cpa">CPA: %1$s, TCPA: %2$s</string>
 
     <!-- ===== Подписи в навигационных виджетах (компас + координаты) ===== -->
     <string name="compass_label_heading">КУРС</string>

app/src/test/java/com/grigowashere/aismap/utils/RangeMathTest.java

@@ -86,4 +86,60 @@ public class RangeMathTest {
         assertTrue("Distance Moscow-SPB ~ 633km, got=" + d,
                 Math.abs(d - 633_000.0) < 10_000.0);
     }
+
+    @Test
+    public void testAisValidityHelpers() {
+        assertTrue(RangeMath.isValidAisSpeed(0.0));
+        assertTrue(RangeMath.isValidAisSpeed(10.5));
+        assertFalse(RangeMath.isValidAisSpeed(102.3));
+        assertFalse(RangeMath.isValidAisSpeed(Double.NaN));
+
+        assertTrue(RangeMath.isValidAisCourse(359.9));
+        assertFalse(RangeMath.isValidAisCourse(360.0));
+        assertFalse(RangeMath.isValidAisHeading(511.0));
+        assertTrue(RangeMath.isValidAisHeading(90.0));
+    }
+
+    @Test
+    public void testCpaHeadOnClosure() {
+        double lat = 55.0;
+        double ownLon = 37.0;
+        double tgtLon = 37.0;
+        double nm = RangeMath.METERS_PER_NM;
+        double tgtLat = lat + (nm / 111_320.0);
+
+        RangeMath.CpaResult r = RangeMath.calculateCpa(
+                lat, ownLon, 10.0, 0.0, Double.NaN,
+                tgtLat, tgtLon, 10.0, 180.0, Double.NaN);
+        assertTrue(r.valid);
+        assertTrue("CPA head-on should be small, got " + r.cpaMeters, r.cpaMeters < 200.0);
+        assertTrue("TCPA head-on should be positive, got " + r.tcpaMinutes, r.tcpaMinutes > 0.0);
+        assertTrue("TCPA head-on ~3 min, got " + r.tcpaMinutes,
+                Math.abs(r.tcpaMinutes - 3.0) < 0.5);
+    }
+
+    @Test
+    public void testCpaParallelSameVectorsInvalidTcpa() {
+        RangeMath.CpaResult r = RangeMath.calculateCpa(
+                55.0, 37.0, 10.0, 90.0, Double.NaN,
+                55.0, 37.01, 10.0, 90.0, Double.NaN);
+        assertFalse(r.valid);
+    }
+
+    @Test
+    public void testCpaMissingCourseInvalid() {
+        RangeMath.CpaResult r = RangeMath.calculateCpa(
+                55.0, 37.0, 5.0, 360.0, Double.NaN,
+                55.01, 37.0, 5.0, 90.0, Double.NaN);
+        assertFalse(r.valid);
+    }
+
+    @Test
+    public void testCpaUsesHeadingOverCog() {
+        RangeMath.CpaResult withHdg = RangeMath.calculateCpa(
+                55.0, 37.0, 10.0, 0.0, 90.0,
+                55.0, 37.01, 10.0, 0.0, 270.0);
+        assertTrue(withHdg.valid);
+        assertTrue(withHdg.cpaMeters < 500.0);
+    }
 }