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SDRstore.eu • 06/16/2026

AIS Ship Tracking with RTL-SDR: Antenna, Software, and Setup Guide

AIS ship tracking is one of the best RTL-SDR projects after ADS-B aircraft tracking. With a low-cost receive-only SDR, a suitable VHF marine antenna, and free decoder software, you can receive Automatic Identification System broadcasts from nearby ships and display vessel positions, MMSI numbers, course, speed, and related maritime data.

AIS is used by ships and shore stations for vessel awareness and maritime safety. It operates in the VHF marine band on two main channels: AIS 1 at 161.975 MHz and AIS 2 at 162.025 MHz. These frequencies are close enough that a single RTL-SDR can normally receive both channels at the same time using software such as AIS-catcher or rtl_ais.

This guide explains how to build an AIS ship-tracking receiver with RTL-SDR, what antenna to use, which software to install, how to send AIS NMEA data to OpenCPN, and how to fix the most common reception problems.

Browse current hardware in the RTL-SDR receivers, kits, antennas, and accessories category. For broader Raspberry Pi SDR projects, read Best SDR for Raspberry Pi: RTL-SDR, ADS-B, AIS, Satellites, and Remote Monitoring.

Quick Answer: Can RTL-SDR Track Ships with AIS?

Yes. RTL-SDR can receive AIS ship-tracking signals on 161.975 MHz and 162.025 MHz when paired with a suitable VHF marine antenna and AIS decoder software. For most beginners, the easiest modern software choice is AIS-catcher. The classic lightweight option is rtl_ais.

Setup part	Recommended choice	Why it matters
Receiver	RTL-SDR Blog V3 USB-C or RTL-SDR Blog V3 Kit	Affordable receive-only SDR with stable TCXO and support for Windows, Linux, Raspberry Pi, and Android
Antenna	VHF marine antenna or adjustable dipole tuned around 162 MHz	AIS is in the VHF maritime band, not at 1090 MHz like ADS-B
Beginner decoder	AIS-catcher	Modern dual-channel AIS receiver with NMEA, web, UDP, HTTP, and TCP output options
Classic decoder	rtl_ais	Lightweight dual-frequency AIS decoder that outputs AIVDM/AIVDO NMEA sentences
Map display	OpenCPN or AIS-catcher web viewer	Displays decoded vessel information visually
Permanent station	Raspberry Pi	Low-power always-on AIS receiver for home, marina, coastal, or educational use

What Is AIS?

AIS stands for Automatic Identification System. It is a VHF maritime data system used by ships, base stations, aids to navigation, and related maritime equipment to broadcast identification and navigation information.

Depending on the vessel and message type, AIS data can include:

MMSI number
Vessel name
Call sign
Ship type
Position
Course over ground
Speed over ground
Heading
Navigation status
Destination and ETA where transmitted
Aids-to-navigation and safety-related information

For an RTL-SDR user, AIS is a receive-only learning project. It can show nearby maritime traffic, but it should not be treated as a certified navigation or safety system.

AIS Frequencies: AIS 1 and AIS 2

The two main AIS frequencies are:

AIS channel	Marine channel	Frequency	Common name
AIS 1	Channel 87B	161.975 MHz	Channel A
AIS 2	Channel 88B	162.025 MHz	Channel B

Because the two channels are only 50 kHz apart, a single RTL-SDR has enough bandwidth to receive both at once. This is different from some multi-frequency projects where the signals are too far apart for one RTL-SDR.

AIS vs ADS-B: Ship Tracking vs Aircraft Tracking

AIS and ADS-B are conceptually similar because both broadcast position and identity information, but they use different frequencies, antennas, software, and applications.

Feature	AIS	ADS-B
Main use	Ship and maritime traffic tracking	Aircraft tracking
Main frequency	161.975 MHz and 162.025 MHz	1090 MHz
Antenna type	VHF marine antenna around 162 MHz	1090 MHz ADS-B antenna
Beginner software	AIS-catcher or rtl_ais	dump1090, readsb, tar1090, PiAware
Output	AIS NMEA messages and ship positions	Aircraft positions and flight data
Best location	Near coast, river, port, marina, canal, or lake traffic	With clear sky view toward aircraft

Do not use a dedicated 1090 MHz ADS-B antenna for AIS if you want best results. AIS needs a VHF antenna closer to 162 MHz.

Recommended RTL-SDR Hardware for AIS

RTL-SDR Blog V3 USB-C

The RTL-SDR Blog V3 USB-C dongle is a strong current choice if you already have or plan to buy a suitable AIS antenna. It includes a 1PPM TCXO for frequency stability, SMA connector, aluminum case, USB-C interface, and support for Windows, Linux, Raspberry Pi, and Android.

RTL-SDR Blog V3 Kit

The RTL-SDR Blog V3 Kit is better for beginners who want everything needed for first tests in one box. The included multipurpose dipole can be adjusted for VHF reception and is useful for learning antenna placement before buying a dedicated outdoor marine antenna.

Do you need RTL-SDR V4 for AIS?

No. AIS is around 162 MHz, where the RTL-SDR Blog V3 already works well. If you already own an RTL-SDR Blog V4, it can also be used, but V3 or V3 USB-C is normally a safe and practical buying direction for AIS.

Best Antenna for AIS with RTL-SDR

AIS reception depends heavily on antenna placement. A better antenna location can improve results more than changing the SDR dongle.

Best antenna choices

Dedicated VHF marine antenna tuned around 156–162 MHz
Outdoor vertical antenna for a permanent coastal or marina station
Adjustable RTL-SDR dipole tuned around 162 MHz for beginner testing
VHF discone or wideband receiving antenna for general marine-band monitoring

Beginner dipole length

A quarter-wave element for 162 MHz is approximately 46 cm. For a simple vertical dipole-style test, extend each element to around 46 cm as a starting point, then adjust placement and orientation for best reception.

The exact result depends on the antenna design, cable, mount, nearby objects, and indoor or outdoor placement. If you use the RTL-SDR Blog multipurpose dipole, treat this as a practical starting length rather than a laboratory-calibrated antenna.

Antenna placement tips

Place the antenna as high as possible.
Use a window or outdoor location facing the water.
Avoid placing the antenna next to laptops, monitors, routers, LED lights, and power supplies.
Use a shorter cable when possible.
If outdoors, protect connectors from moisture.
If you are far inland, do not expect much AIS traffic unless there are rivers, canals, ports, or lakes nearby.

How Far Can RTL-SDR Receive AIS?

AIS range is mainly limited by VHF line-of-sight. A low indoor antenna may only receive nearby vessels. A high outdoor antenna near the coast can receive much farther.

Setup	Typical result
Indoor antenna far from water	Very limited or no AIS messages
Indoor window antenna near a river or marina	Nearby vessels may decode
Outdoor antenna near coast or port	Good local ship tracking
High outdoor antenna with clear sea view	Best range for a low-cost RTL-SDR station

AIS is not a satellite-tracking project for normal RTL-SDR stations. You are mostly receiving local terrestrial VHF signals from ships and shore stations within radio range.

Best AIS Decoder Software for RTL-SDR

Software	Best for	Output	Beginner recommendation
AIS-catcher	Modern dual-channel AIS reception, web viewing, and network output	NMEA, UDP, TCP, HTTP, web interface, and other options	Best first choice for most users
rtl_ais	Lightweight classic command-line decoding	AIVDM and AIVDO NMEA sentences	Good for simple Linux or Raspberry Pi setups
OpenCPN	Chart display and AIS target visualization	NMEA input from AIS decoder	Best when you want a chart-plotter-style display
SDR++ or SDR#	Visual signal checking	Waterfall and spectrum view	Useful before debugging decoder commands

Windows Setup with AIS-catcher

On Windows, AIS-catcher is usually the easiest decoder to start with because pre-built binaries are available and the software can output decoded data without requiring a full Linux build environment.

Step 1: Install RTL-SDR drivers

Install the RTL-SDR driver with Zadig, then test the dongle in SDR# or SDR++ first. If the receiver is not visible in normal SDR software, AIS-catcher will not fix the driver issue.

Read the full Windows driver guide: RTL-SDR Setup Guide for Windows: SDR#, SDR++, Zadig, Drivers, and First Signal.

Step 2: Download and unpack AIS-catcher

Download the current AIS-catcher Windows release from the official project page, unpack the ZIP file into a folder, and open Command Prompt in that folder.

Step 3: Run a first test

AIS-catcher

If your RTL-SDR is detected and the antenna can hear AIS traffic, messages should begin appearing. If nothing appears, keep the software simple and improve antenna placement first.

Step 4: Set RTL-SDR gain manually

AIS-catcher -gr tuner 33.3 rtlagc ON

This sets the tuner gain and enables RTL AGC as a starting test. The best gain depends on your signal environment. Too much gain can overload the receiver, while too little gain can miss weak vessels.

Linux and Raspberry Pi Setup with AIS-catcher

Linux and Raspberry Pi are good choices for permanent AIS stations. Start manually before creating services or automatic startup scripts.

Step 1: Install RTL-SDR tools

sudo apt update
sudo apt install rtl-sdr
rtl_test

If rtl_test cannot see the receiver, fix RTL-SDR drivers or permissions before installing AIS software.

Step 2: Install AIS-catcher

Use the official AIS-catcher installation instructions for your distribution. Package availability and build steps can change, so follow the current project documentation when building a production station.

Step 3: Run a basic AIS-catcher test

AIS-catcher

Step 4: Adjust gain

AIS-catcher -gr tuner 33.3 rtlagc ON

Step 5: Add frequency correction if needed

Genuine RTL-SDR Blog receivers include a stable TCXO, so correction is usually small. If needed, AIS-catcher supports frequency correction through its RTL-SDR settings.

AIS-catcher -gr freqoffset 1 tuner 33.3

Use a measured correction value rather than guessing.

Classic Setup with rtl_ais

rtl_ais is a lightweight command-line AIS decoder. It defaults to the two normal AIS frequencies and outputs AIVDM/AIVDO NMEA sentences.

Build rtl_ais on Linux

sudo apt update
sudo apt install git build-essential librtlsdr-dev libusb-1.0-0-dev

git clone https://github.com/dgiardini/rtl-ais.git
cd rtl-ais
make
sudo make install

Run rtl_ais with console logging

rtl_ais -n

By default, rtl_ais uses 161.975 MHz and 162.025 MHz. These are the two normal AIS channels, so most users do not need to set frequencies manually.

Set gain and PPM correction

rtl_ais -g 38.6 -p 1 -n

Adjust gain and PPM correction for your receiver and local signal conditions. If messages are noisy or rare, check the antenna and gain before changing many software options at once.

Send NMEA to OpenCPN over UDP

rtl_ais -h 127.0.0.1 -P 10110 -n

This sends AIS NMEA sentences to UDP port 10110 on the same computer. You can then configure OpenCPN to listen for incoming NMEA data.

View AIS Targets in OpenCPN

OpenCPN is a free and open-source chart-plotter application. It can receive AIS NMEA data from software such as AIS-catcher or rtl_ais and display vessel targets on a chart.

Basic OpenCPN workflow

Install OpenCPN.
Start AIS-catcher or rtl_ais and confirm that NMEA messages are being produced.
Open OpenCPN settings.
Add a network connection for NMEA input.
Use UDP or TCP according to the decoder output.
Set the port, commonly 10110 for local AIS NMEA testing.
Confirm AIS targets appear on the chart.

Important navigation warning

An RTL-SDR plus AIS-catcher or rtl_ais is a hobby and learning setup. It is not a certified AIS receiver, AIS transponder, collision-avoidance system, or primary navigation tool. Do not rely on it for safety of life, navigation, or vessel-operation decisions.

Using the AIS-catcher Web Viewer

AIS-catcher can provide a convenient built-in viewer for local station monitoring. This is useful if you want a quick browser-based display without configuring a full chart plotter immediately.

For a beginner station, the workflow is:

Run AIS-catcher.
Confirm messages are decoding.
Open the local web interface if enabled in your configuration.
Check vessel list and map-style output.
Only then add OpenCPN, remote sharing, or automatic startup.

Keep any web viewer limited to your trusted local network unless you understand the security implications of exposing it externally.

Should You Feed AIS Data Online?

Some communities allow users to share AIS receiver data. Before feeding or forwarding decoded data, check your local laws and the terms of the receiving platform.

Responsible sharing checklist:

Confirm AIS reception and data sharing is legal in your country.
Do not rely on a hobby receiver for navigation.
Do not publish misleading station data.
Secure any web dashboards or network outputs.
Use the latest stable software release when sharing data continuously.
Keep logs only when needed and handle data responsibly.

Gain, AGC, and Frequency Correction

AIS decoding is sensitive to signal quality. The goal is not maximum gain. The goal is clean decoding.

Gain tips

Start with a moderate gain value, such as around 30–40 dB.
Reduce gain if strong local signals overload the receiver.
Increase gain only if AIS bursts are weak and the noise floor remains controlled.
Try manual gain and automatic gain options to see which works best in your location.

Frequency correction tips

RTL-SDR Blog receivers use a 1PPM TCXO, so correction is usually small. If decoding is unreliable, check PPM correction with RTL-SDR tools and apply a measured value.

rtl_test -p

Let the test run long enough to estimate correction, then apply the result in AIS-catcher or rtl_ais if needed.

Filters and LNAs for AIS

AIS is close to the marine VHF band, so strong local transmitters, pagers, FM broadcast stations, or other nearby RF sources can affect reception.

When a filter helps

The waterfall looks overloaded.
Strong nearby signals raise the noise floor.
AIS bursts are visible but decoding is poor.
The receiver is near strong broadcast or marine transmitters.

A broadcast FM block filter can help in some overloaded VHF environments. View the Broadcast FM Block Filter.

When an LNA helps

An LNA may help if the antenna is outdoors, the signal is weak, and the coax cable run is long. It can also make reception worse if the receiver is already overloaded.

Read Do You Need an LNA for SDR?

Permanent AIS Station on Raspberry Pi

A Raspberry Pi is ideal for a permanent AIS station because it can run continuously with low power consumption. Build the station only after manual decoding works.

Recommended process

Install Raspberry Pi OS.
Connect the RTL-SDR directly or through a reliable powered USB hub.
Run rtl_test.
Install AIS-catcher or rtl_ais.
Run the decoder manually.
Adjust antenna placement and gain.
Confirm stable messages for several hours.
Create a systemd service only after the manual command works.
Log output and monitor service restarts.

What to document

Raspberry Pi model
RTL-SDR serial number
Decoder software and version
Antenna type and height
Gain setting
Frequency correction
Output port for OpenCPN or local web display
Known-good command line

Common AIS with RTL-SDR Problems

Problem	Likely cause	Fix
No vessels appear	No nearby AIS traffic, poor antenna location, or wrong setup	Move closer to water, raise the antenna, and test with a known active area.
RTL-SDR not found	Driver or permissions issue	Run `rtl_test`, fix Zadig on Windows, or fix Linux udev permissions.
Messages appear rarely	Weak signal or low vessel traffic	Improve antenna height, placement, and view toward the water.
Decoder shows errors	Overload, poor SNR, wrong gain, or frequency offset	Adjust gain, check PPM correction, and inspect the signal in SDR++.
OpenCPN shows no targets	NMEA output is not connected correctly	Confirm AIS NMEA messages first, then check UDP/TCP address and port.
Good reception indoors, poor reception after moving outdoors	Cable loss, bad connector, or water ingress	Check cable, adapters, connector sealing, and antenna mount.
Strong signals but bad decoding	Receiver overload	Reduce gain, remove unnecessary LNA, or add filtering.

Recommended AIS Starter Setup

Item	Recommended choice	Reason
Receiver	RTL-SDR Blog V3 USB-C or RTL-SDR Blog V3 Kit	Stable, affordable, receive-only, and suitable for 162 MHz AIS reception
Antenna	VHF marine antenna or adjustable dipole	AIS needs a VHF antenna, not a 1090 MHz ADS-B antenna
Software	AIS-catcher	Modern dual-channel decoder with flexible output options
Alternative software	rtl_ais	Simple classic decoder for AIVDM/AIVDO NMEA output
Display	AIS-catcher web viewer or OpenCPN	Shows decoded vessel data visually
Permanent receiver	Raspberry Pi	Low-power always-on station

Legal and Safety Notes

Radio-monitoring laws vary by country. Check your local rules before receiving, decoding, logging, forwarding, or publishing AIS data.

Receive only. RTL-SDR is receive-only and cannot transmit.
Do not interfere with marine radio services.
Do not use an RTL-SDR AIS setup as a certified navigation system.
Do not rely on hobby receiver data for safety-of-life decisions.
Do not transmit on AIS or marine VHF channels without authorization.
Handle logged vessel data responsibly.
Use official certified marine equipment for real vessel navigation and safety needs.

Related SDRstore.eu Guides

Official and Technical Resources

Final Recommendation

For most beginners, the best AIS ship-tracking setup is an RTL-SDR Blog V3 USB-C or RTL-SDR Blog V3 Kit, a VHF marine antenna or adjustable dipole, and AIS-catcher. Start by confirming that the RTL-SDR works, place the antenna near a window or outdoors with a clear view toward the water, then run AIS-catcher and verify decoded messages.

If you prefer a simple classic command-line decoder, use rtl_ais. If you want a chart-style display, forward NMEA output to OpenCPN. If you want an always-on receiver, move the working command to a Raspberry Pi only after manual testing is stable.

The biggest performance upgrade for AIS is usually not a more expensive receiver. It is a better antenna, higher placement, cleaner VHF signal environment, and correct gain setting.

FAQ

Can RTL-SDR receive AIS ship signals?

Yes. RTL-SDR can receive AIS signals on 161.975 MHz and 162.025 MHz when paired with a suitable VHF marine antenna and AIS decoder software such as AIS-catcher or rtl_ais.

What are the AIS frequencies?

The two main AIS frequencies are 161.975 MHz for AIS 1, channel 87B, and 162.025 MHz for AIS 2, channel 88B.

What is the best AIS software for RTL-SDR?

AIS-catcher is the best modern beginner recommendation because it supports dual-channel AIS reception, RTL-SDR devices, NMEA output, network forwarding, and a web viewer. rtl_ais is a lightweight classic alternative.

Can one RTL-SDR receive both AIS channels?

Yes. AIS 1 and AIS 2 are only 50 kHz apart, so one RTL-SDR can normally receive both channels at the same time using software such as AIS-catcher or rtl_ais.

Can I use an ADS-B antenna for AIS?

A dedicated 1090 MHz ADS-B antenna is not ideal for AIS. Use a VHF marine antenna, VHF discone, or adjustable dipole tuned around 162 MHz.

How far can RTL-SDR receive AIS?

AIS range depends on VHF line-of-sight, antenna height, location, and nearby vessel traffic. A high outdoor antenna near the coast or a port will perform much better than a small indoor antenna far from water.

Can I run AIS decoding on Raspberry Pi?

Yes. Raspberry Pi is a good platform for a permanent AIS receiver. First test manually with rtl_test and AIS-catcher or rtl_ais, then create an automatic service only after decoding is stable.

Can I display RTL-SDR AIS data in OpenCPN?

Yes. AIS-catcher or rtl_ais can output AIS NMEA sentences, which can be sent to OpenCPN over UDP or TCP for chart-style vessel display.

Why am I not seeing any AIS ships?

The most common reasons are no nearby vessel traffic, poor antenna placement, wrong antenna type, RTL-SDR driver problems, excessive gain, receiver overload, or being too far inland.

Is RTL-SDR AIS safe for navigation?

No. An RTL-SDR AIS setup is for learning, monitoring, and experimentation. Do not use it as a certified navigation, collision-avoidance, or safety-of-life system.

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