feat(export): AIS UDP NMEA forward and JSON export endpoints for AIS/ADS-B

AIS:
- New optional NMEA UDP forwarding via AIS-catcher's -u flag, configurable
  from the AIS sidebar (host + port). Lets OpenCPN and other NMEA tools
  receive live vessel data directly. All SDR builders updated.
- New GET /ais/vessels endpoint — clean JSON snapshot of tracked vessels
  for REST integration

ADS-B:
- New GET /adsb/aircraft endpoint — JSON snapshot of all tracked aircraft,
  with optional ?icao= and ?military=true filters. Response includes a
  reminder that port 30003 (SBS) is already available for tools like
  Virtual Radar Server and OpenCPN's AIS/target plugin.

Closes #90

routes/adsb.py

@@ -803,6 +803,41 @@ def adsb_status():
     })
 
 
+@adsb_bp.route('/aircraft')
+def adsb_aircraft_export():
+    """Export current ADS-B aircraft data as JSON.
+
+    Returns a snapshot of all tracked aircraft suitable for integration
+    with external tools. For SBS (BaseStation) format, connect directly
+    to port 30003 which dump1090 exposes natively.
+
+    Query parameters:
+        icao: Filter to a specific ICAO hex code (optional)
+        military: 'true' to return only military aircraft (optional)
+
+    Returns:
+        JSON with aircraft list and metadata.
+    """
+    aircraft = dict(app_module.adsb_aircraft)
+
+    icao_filter = request.args.get('icao', '').upper()
+    if icao_filter:
+        aircraft = {k: v for k, v in aircraft.items() if k.upper() == icao_filter}
+
+    if request.args.get('military') == 'true':
+        try:
+            from utils.military_icao import is_military_icao
+            aircraft = {k: v for k, v in aircraft.items() if is_military_icao(k)}
+        except ImportError:
+            pass
+
+    return jsonify({
+        'count': len(aircraft),
+        'aircraft': list(aircraft.values()),
+        'sbs_port': 30003,  # dump1090 SBS stream for tools like Virtual Radar Server
+    })
+
+
 @adsb_bp.route('/session')
 def adsb_session():
     """Get ADS-B session status and uptime."""

routes/ais.py

@@ -408,11 +408,24 @@ def start_ais():
     bias_t = data.get('bias_t', False)
     tcp_port = AIS_TCP_PORT
 
+    # Optional UDP NMEA forwarding (e.g. for OpenCPN on port 10110)
+    udp_host = data.get('udp_host') or None
+    udp_port = None
+    if udp_host:
+        try:
+            udp_port = int(data.get('udp_port', 10110))
+            if not 1 <= udp_port <= 65535:
+                raise ValueError
+        except (TypeError, ValueError):
+            return api_error('Invalid udp_port (1-65535)', 400)
+
     cmd = builder.build_ais_command(
         device=sdr_device,
         gain=float(gain),
         bias_t=bias_t,
-        tcp_port=tcp_port
+        tcp_port=tcp_port,
+        udp_host=udp_host,
+        udp_port=udp_port,
     )
 
     # Use the found AIS-catcher path
@@ -535,6 +548,31 @@ def get_vessel_dsc(mmsi: str):
     return api_success(data={'mmsi': mmsi, 'dsc_messages': matches})
 
 
+@ais_bp.route('/vessels')
+def ais_vessels():
+    """Export current AIS vessel data as JSON.
+
+    Returns a snapshot of all tracked vessels suitable for integration
+    with external tools (OpenCPN, ship tracking apps, etc.).
+
+    Query parameters:
+        mmsi: Filter to a specific MMSI (optional)
+
+    Returns:
+        JSON with vessel list and metadata.
+    """
+    vessels = dict(app_module.ais_vessels)
+
+    mmsi_filter = request.args.get('mmsi')
+    if mmsi_filter:
+        vessels = {k: v for k, v in vessels.items() if str(k) == str(mmsi_filter)}
+
+    return jsonify({
+        'count': len(vessels),
+        'vessels': list(vessels.values()),
+    })
+
+
 @ais_bp.route('/dashboard')
 def ais_dashboard():
     """Popout AIS dashboard."""

templates/partials/modes/ais.html

@@ -18,6 +18,23 @@
         </div>
     </div>
 
+    <div class="section">
+        <h3>NMEA UDP Forward</h3>
+        <p class="info-text" style="font-size: 11px; color: var(--text-dim); margin-bottom: 8px;">
+            Forward NMEA 0183 sentences to an external app (e.g. OpenCPN). Leave host blank to disable.
+        </p>
+        <div style="display: flex; gap: 8px;">
+            <div style="flex: 2;">
+                <label style="font-size: 10px; color: var(--text-dim);">Host</label>
+                <input type="text" id="aisUdpHost" placeholder="e.g. 192.168.1.10" style="width: 100%;">
+            </div>
+            <div style="flex: 1;">
+                <label style="font-size: 10px; color: var(--text-dim);">Port</label>
+                <input type="number" id="aisUdpPort" value="10110" min="1" max="65535" style="width: 100%;">
+            </div>
+        </div>
+    </div>
+
     <div class="section">
         <h3>Status</h3>
         <div id="aisStatusDisplay" class="info-text">
@@ -110,11 +127,22 @@
     function startAisTracking() {
         const gain = document.getElementById('aisGainInput').value || '40';
         const device = document.getElementById('deviceSelect')?.value || '0';
+        const udpHost = document.getElementById('aisUdpHost').value.trim();
+        const udpPort = parseInt(document.getElementById('aisUdpPort').value) || 10110;
+
+        const body = {
+            device, gain,
+            bias_t: typeof getBiasTEnabled === 'function' ? getBiasTEnabled() : false,
+        };
+        if (udpHost) {
+            body.udp_host = udpHost;
+            body.udp_port = udpPort;
+        }
 
         fetch('/ais/start', {
             method: 'POST',
             headers: { 'Content-Type': 'application/json' },
-            body: JSON.stringify({ device, gain, bias_t: typeof getBiasTEnabled === 'function' ? getBiasTEnabled() : false })
+            body: JSON.stringify(body)
         })
         .then(r => r.json())
         .then(data => {

utils/sdr/airspy.py

@@ -161,7 +161,9 @@ class AirspyCommandBuilder(CommandBuilder):
         device: SDRDevice,
         gain: float | None = None,
         bias_t: bool = False,
-        tcp_port: int = 10110
+        tcp_port: int = 10110,
+        udp_host: str | None = None,
+        udp_port: int | None = None,
     ) -> list[str]:
         """
         Build AIS-catcher command for AIS vessel tracking with Airspy.
@@ -184,6 +186,9 @@ class AirspyCommandBuilder(CommandBuilder):
         if bias_t:
             cmd.extend(['-gr', 'biastee', '1'])
 
+        if udp_host and udp_port:
+            cmd.extend(['-u', udp_host, str(udp_port)])
+
         return cmd
 
     def build_iq_capture_command(

utils/sdr/base.py

@@ -165,7 +165,9 @@ class CommandBuilder(ABC):
         device: SDRDevice,
         gain: float | None = None,
         bias_t: bool = False,
-        tcp_port: int = 10110
+        tcp_port: int = 10110,
+        udp_host: str | None = None,
+        udp_port: int | None = None,
     ) -> list[str]:
         """
         Build AIS decoder command for vessel tracking.
@@ -175,6 +177,8 @@ class CommandBuilder(ABC):
             gain: Gain in dB (None for auto)
             bias_t: Enable bias-T power (for active antennas)
             tcp_port: TCP port for JSON output server
+            udp_host: Optional host to forward NMEA 0183 sentences via UDP
+            udp_port: UDP port for NMEA forwarding (required if udp_host set)
 
         Returns:
             Command as list of strings for subprocess

utils/sdr/hackrf.py

@@ -161,7 +161,9 @@ class HackRFCommandBuilder(CommandBuilder):
         device: SDRDevice,
         gain: float | None = None,
         bias_t: bool = False,
-        tcp_port: int = 10110
+        tcp_port: int = 10110,
+        udp_host: str | None = None,
+        udp_port: int | None = None,
     ) -> list[str]:
         """
         Build AIS-catcher command for AIS vessel tracking with HackRF.
@@ -184,6 +186,9 @@ class HackRFCommandBuilder(CommandBuilder):
         if bias_t:
             cmd.extend(['-gr', 'biastee', '1'])
 
+        if udp_host and udp_port:
+            cmd.extend(['-u', udp_host, str(udp_port)])
+
         return cmd
 
     def build_iq_capture_command(

utils/sdr/limesdr.py

@@ -140,7 +140,9 @@ class LimeSDRCommandBuilder(CommandBuilder):
         device: SDRDevice,
         gain: float | None = None,
         bias_t: bool = False,
-        tcp_port: int = 10110
+        tcp_port: int = 10110,
+        udp_host: str | None = None,
+        udp_port: int | None = None,
     ) -> list[str]:
         """
         Build AIS-catcher command for AIS vessel tracking with LimeSDR.
@@ -161,6 +163,9 @@ class LimeSDRCommandBuilder(CommandBuilder):
         if gain is not None and gain > 0:
             cmd.extend(['-gr', 'tuner', str(int(gain))])
 
+        if udp_host and udp_port:
+            cmd.extend(['-u', udp_host, str(udp_port)])
+
         return cmd
 
     def build_iq_capture_command(

utils/sdr/rtlsdr.py

@@ -281,7 +281,9 @@ class RTLSDRCommandBuilder(CommandBuilder):
         device: SDRDevice,
         gain: float | None = None,
         bias_t: bool = False,
-        tcp_port: int = 10110
+        tcp_port: int = 10110,
+        udp_host: str | None = None,
+        udp_port: int | None = None,
     ) -> list[str]:
         """
         Build AIS-catcher command for AIS vessel tracking.
@@ -308,6 +310,9 @@ class RTLSDRCommandBuilder(CommandBuilder):
         if bias_t:
             cmd.extend(['-gr', 'BIASTEE', 'on'])
 
+        if udp_host and udp_port:
+            cmd.extend(['-u', udp_host, str(udp_port)])
+
         return cmd
 
     def build_iq_capture_command(

utils/sdr/sdrplay.py

@@ -139,7 +139,9 @@ class SDRPlayCommandBuilder(CommandBuilder):
         device: SDRDevice,
         gain: float | None = None,
         bias_t: bool = False,
-        tcp_port: int = 10110
+        tcp_port: int = 10110,
+        udp_host: str | None = None,
+        udp_port: int | None = None,
     ) -> list[str]:
         """
         Build AIS-catcher command for AIS vessel tracking with SDRPlay.
@@ -162,6 +164,9 @@ class SDRPlayCommandBuilder(CommandBuilder):
         if bias_t:
             cmd.extend(['-gr', 'biastee', '1'])
 
+        if udp_host and udp_port:
+            cmd.extend(['-u', udp_host, str(udp_port)])
+
         return cmd
 
     def build_iq_capture_command(