How to Integrate External GPS and Navigation AIDS in Prepar3d

Prepar3D is a powerful flight simulation platform used by hobbyists, professional pilots, and training organizations for its extensibility and realistic flight dynamics. While the simulator includes built-in GPS and navigation systems, many users seek to integrate external GPS receivers, hardware navigation aids, or third-party software plugins to achieve higher precision, real-world functionality, or a more immersive experience. This guide provides a comprehensive, step-by-step approach to integrating external GPS and navigation aids into Prepar3D, covering hardware devices, software tools, configuration steps, troubleshooting, and best practices. By the end, you will be able to expand your simulation capabilities for more realistic flight planning, navigation, and situational awareness.

External navigation aids refer to any hardware or software tool that provides positioning, route guidance, or navigational data outside of Prepar3D’s default systems. These tools can deliver real-time GPS coordinates, overlay moving maps, display instrument approaches, or integrate with actual avionics hardware. Typical use cases include using a real Garmin GPS unit, connecting a tablet running ForeFlight or Garmin Pilot, or employing specialized mapping software like Little Navmap or Plan-G to provide a standalone navigation display.

External navigation aids can be classified into three main categories:

Hardware GPS Receivers: Physical devices (USB or serial-connected GPS receivers, USB GPS dongles, or even mobile phones acting as GPS data sources) that feed position data into Prepar3D.
Software Navigation Plugins: Standalone applications that communicate with Prepar3D via SimConnect, FSUIPC, or other interfaces to provide moving maps, flight planning, weather overlays, and more.
Networked or Cloud-Based Services: Tools that pull data from online sources for real-time weather, traffic, or navigation databases and display them within or alongside the simulator.

Before diving into integration, it’s important to confirm that your chosen external aid is compatible with your version of Prepar3D (v3, v4, or v5+). Many older plugins and drivers may require updates or patches to work with the latest Prepar3D builds.

Choosing the Right Tools for Your Setup

Hardware GPS Devices

External GPS hardware connects to your PC via USB, serial (COM) port, or Bluetooth. Popular devices include the GlobalSat BU-353-S4, Garmin GPS 18x, or the VK-162 USB GPS dongle. These receivers output NMEA sentences that Prepar3D or third-party software can interpret. When selecting a hardware GPS, consider:

Connection type: USB is simplest; serial requires a COM port configuration.
Update rate: 1 Hz (standard) to 10 Hz (higher precision for fast aircraft).
Compatibility: Some units require specific drivers to be installed.
Form factor: Small dongles for desktop use or larger puck-style receivers for more accurate signal reception.

For users who already own a GPS device used in real aircraft, compatibility can often be achieved through custom FSUIPC configurations or dedicated bridge software.

Software Plugins and Standalone Map Tools

Software-based navigation aids are the most flexible and widely used approach. Key options include:

Little Navmap: A free, open-source flight planner and moving map that connects via SimConnect. It supports real-time aircraft position display, navigational database updates, and integration with online services like VATSIM or IVAO. Download from Little Navmap.
Plan-G: A feature-rich flight planner and moving map with approach charts, terrain profiles, and GPS simulation. Works with Prepar3D via SimConnect. Available at Plan-G.
SimPlates: An external approach chart viewer that syncs with your flight path.
Custom Panels using Air Manager or SimVim: These tools allow you to build your own GPS or MFD panels that interact with real GPS hardware.

Most of these tools are free or offer trial versions. They provide a robust set of features that far exceed the default GPS capabilities in Prepar3D.

Cloud-based solutions such as Navigraph Charts, Avare (for iPad), or Web-based flight planning tools can feed data into Prepar3D via plugins or by sharing screen data. For instance, Navigraph integrates directly with Little Navmap and some payware aircraft to provide up-to-date nav databases and chart overlays. While not strictly external hardware, these services act as navigation aids that enhance situational awareness.

Integrating External GPS Devices with Prepar3D

Step 1: Install Drivers and Confirm Hardware Recognition

Before launching Prepar3D, install any required drivers for your GPS receiver. For USB GPS devices, the system usually recognizes them as a serial port (COM port) or as a Human Interface Device. Connect the GPS receiver, then open Device Manager to verify the assigned COM port number. If the device uses a virtual COM port driver (e.g., Silicon Labs CP210x or Prolific PL2303), install those drivers from the manufacturer’s website.

Step 2: Configure the GPS Device to Output NMEA Sentences

Most USB GPS receivers output NMEA 0183 sentences by default. However, you may need to configure the baud rate and sentence types using free tools like u-center (for u-blox receivers) or GPS Info Viewer. For compatibility with Prepar3D, ensure the device outputs either GPS or GNSS position sentences (GGA, RMC). Set a baud rate of 4800 or 57600; Prepar3D accepts any standard rate if configured correctly.

Step 3: Connect the GPS to Prepar3D Using a Bridge

Prepar3D itself does not natively read NMEA data from an external serial GPS. You need an intermediary program that interprets NMEA and writes the position into the simulator via SimConnect or offsets. Two common approaches are:

Using FSUIPC: FSUIPC (registered version) can read NMEA from a COM port and map it to aircraft position. In FSUIPC, go to the GPS tab and configure the serial port, baud rate, and NMEA sentence mappings. This is a robust method that works with any aircraft.
Using dedicated bridge software: Tools like FS GPS Bridge or custom scripts in Python/AutoHotkey can relay NMEA to SimConnect. For example, the freeware program “GPS2Sim” offers a GUI to forward GPS data.
Using Little Navmap’s GPS Input: Little Navmap can read a COM port directly and display your position on its map, but it does not override the aircraft position in Prepar3D. This is useful for situational awareness but not for actual navigation.

If you want the external GPS to actually move the simulated aircraft position (for example, for training with a real GPS unit), the FSUIPC method is recommended. Otherwise, using a moving map display that follows the external GPS is sufficient for many users.

Step 4: Configure Prepar3D to Accept External Position Data

When using FSUIPC to inject the external GPS position, ensure that “Allow external GPS override” is checked in the Prepar3D settings (located in Options – Controls – GPS). Also disable any internal GPS conflict by turning off the default GPS panel if you are relying entirely on the external unit. In the aircraft’s avionics stack, some payware aircraft allow switching between internal and external GPS sources—consult the aircraft manual.

Step 5: Calibrate and Test

Start Prepar3D, spawn your aircraft at an airport, and then activate the FSUIPC GPS override. The aircraft position should jump to match the GPS coordinates from your external receiver. Verify by comparing the position shown in Little Navmap or the default map view. Ensure the update rate is smooth and that the aircraft responds to your physical movement (if you have a portable setup).

Step 1: Download and Install the Software

Choose a navigation aid such as Little Navmap or Plan-G. Download the latest version from the official website and install it. During installation, ensure you select the correct architecture (32-bit vs 64-bit) to match your Prepar3D version. For Prepar3D v4+, use the 64-bit versions of these tools.

Step 2: Establish SimConnect Connection

Both Little Navmap and Plan-G use SimConnect to read aircraft position, attitude, and other data from Prepar3D. SimConnect is installed automatically with Prepar3D, but you may need to manually start the SimConnect service or place a configuration file in the Prepar3D root directory. Most software provides a “Connect” button—click it and verify the connection status indicator turns green. If connection fails, check that Prepar3D is running, and that no firewall is blocking the local SimConnect port (usually 5000–5010).

Once connected, the software will show your aircraft on a map. Customize the layers: choose map style (VFR, IFR, terrain, satellite), enable navaids (VORs, NDBs, waypoints), approach procedures, airspace boundaries, and weather overlays. For realistic flight planning, load a flight plan from SimBrief or manually create one and export it to both the software and Prepar3D.

Step 4: Sync Real-Time Data

Ensure the software updates the aircraft position in real time (usually every 0.5 to 1 second). Verify that the map pans automatically. Many programs also support twin windows: one for the flight plan view and one for the moving map. You can drag these windows to a second monitor or overlay them using transparent backgrounds (some tools support windowed mode with click-through).

Step 5: Integrate with Hardware (Optional)

Some navigation software can also send data back to Prepar3D, such as autopilot commands or GPS destination waypoints. For example, Little Navmap can send “direct to” waypoint commands to the simulator via SimConnect, which is useful for flight simulation training. Explore the software’s “User Interface” or “Actions” settings to enable two-way communication.

Advanced Configuration and Optimization

It is possible to run both a hardware GPS and a software moving map together. For instance, use FSUIPC to inject external GPS position into the simulator, while Little Navmap reads that injected position and displays it. This gives you a real GPS source and a rich map display simultaneously. Ensure that only one software writes to the SimConnect aircraft position to avoid conflicts; FSUIPC can be set as the master, and other tools should be in read-only mode for position data.

Integrating with Avionics Panels (e.g., Garmin G1000)

If you use payware aircraft with custom avionics (e.g., PMDG, Aerosoft CRJ, Flight1 GTN 750), you may be able to feed external GPS data directly into the simulated GPS unit. The Flight1 GTN 750/650 packages, for example, can be driven by external NMEA data through a configuration file. Check the aircraft or avionics manual for “External GPS” or “XGPS” settings. This provides the most realistic integration, where your physical GPS moves the needles on the simulated glass cockpit.

Performance Considerations

Running multiple external tools can consume CPU resources and potentially increase load times. Adjust update intervals in the software to every 300–500ms instead of 100ms if you notice stutter. Also disable unnecessary map layers (e.g., high-resolution satellite images when flying in remote areas). For hardware GPS devices, use a dedicated USB controller to avoid sharing bandwidth with other peripherals like joysticks or mice.

Testing and Troubleshooting

Pre-Flight Check

Before each session, verify that the external GPS device has a solid fix (flashing LED typically indicates no fix). Open the FSUIPC GPS window or the bridge software to confirm NMEA data is being received. Check that the software map is centered on your aircraft and that the position matches known coordinates (e.g., a runway threshold). If using FSUIPC, perform a quick taxi on the ground to see if the aircraft moves smoothly.

Common Issues and Fixes

No GPS signal in Prepar3D: Ensure the COM port is not in use by another program (e.g., a serial terminal). Force close any GPS logging software. Try a different USB port or use a USB hub with external power if the GPS draws too much current.
Position jumps or is inaccurate: The GPS may have a poor satellite lock (indoors or near tall buildings). Move the antenna to a window or outdoors. Also check that the baud rate matches between device and FSUIPC.
Little Navmap shows “No SimConnect data”: Run Prepar3D as administrator; SimConnect may be blocked by UAC. Reinstall SimConnect from the Prepar3D redist folder. Ensure the correct version (64-bit) is installed.
Stuttering or lag on the map display: Reduce the map refresh rate. In Little Navmap, go to Tools – Options – Display and set “Update rate” to 300ms. Disable weather overlays if not needed.
External GPS overrides but aircraft doesn’t move: In FSUIPC, ensure you selected the correct method (e.g., “NMEA GPS” over “Simulator” under the GPS tab). Some aircraft have a weight-on-wheels lock; engage the parking brake or set the engine state.

Community Support and Resources

If you encounter unique issues, consult the Prepar3D Forums for specific threads on external GPS integration. The FSUIPC manual (available with the registered version) contains detailed chapters on GPS configuration. The Little Navmap documentation also offers troubleshooting for connection problems.

Best Practices for a Realistic Experience

Use a dedicated second screen: Deploy the moving map on a separate monitor or tablet (using apps like Duet Display or Spacedesk). This keeps the main screen clear for cockpit view.
Update navigation databases: For accurate waypoints and procedures, subscribe to Navigraph or update the free nav data via the FS Navigraph Data Updater. Outdated databases can misalign routes.
Simulate instrument failures: Use external GPS to simulate the loss of internal navigation. Turn off the default GPS in the sim and rely solely on the external unit and a paper chart to train for real-world failures.
Log flights for debriefing: Many navigation aids allow recording of flight paths. Export GPS logs to CSV for analysis in Google Earth or flight tracking platforms.
Combine with weather radar: Some moving map tools can overlay active weather from Active Sky or FSXWX, giving you real-time threat avoidance.

Conclusion

Integrating external GPS and navigation aids into Prepar3D dramatically enhances both realism and functionality. Whether you connect a physical GPS receiver to train with real hardware, use a powerful moving map software for better situational awareness, or combine both for a hybrid setup, the process is accessible with the right tools and configuration. By following the detailed steps outlined above—from choosing compatible devices and bridging NMEA data to troubleshooting common issues—you can build a highly customized navigation environment that meets your simulation goals. Regularly update your software, consult community resources, and experiment with different setups to find what works best for your flying style. With external navigation aids, the skies become even more immersive and educational.