ATAK Forwarder

An ATAK plugin for forwarding CoT messages via a hardware layer. Currently supports Meshtastic devices.

Binaries signed for the Play Store version of ATAK are available here: Binaries

IMPORTANT NOTE: All configuration options / Tracker writing have been moved into ATAK's three button (kebab) menu under Settings > Tool Preferences > Specific Tool Preferences > ATAK Forwarder

Share Markers and PLI

Send Chat Messages

Configurable Channel Settings / Share with QR

Use standalone Meshtastic devices as Trackers

Features

• In-app device and channel management
• Broadcast messages are sent to the channel (e.g. map markers, PLI)
• Direct messages to other users (e.g. chat messages)
• Support for Meshtastic devices without an ATAK EUD attached
• Efficient comm. using libcotshrink -- can send approx 5 map markers or PLI per minute, or 2 chats, or 2.5 more complex markers
• Typical msg sizes, PLI: ~190 bytes, simple shape ~200 bytes, complex shape ~250 bytes, ~380 bytes, group chat ~400 bytes
• Filtering of repeated messages with a configurable TTL (e.g. to prevent auto-send markers from flooding)
• Message queue with priority (chat = pli > markers)

Beta Features

• Support for USB devices -- early stage, you might need to pair the device in the Meshtastic app to get USB permissions before setting it up in ATAK

Supported Versions

The plugin has been tested with these versions of the Meshtastic dependencies. If you run into issues try installing these versions of the Meshtastic software to resolve them.

Dependency	Version
Meshtastic-Android	1.2.64
Meshtastic-device	1.2.64

To Do

• Remote channel management / updating
• Automatically adjust link speed / range based on # of lost messages
• Use T-Beam as a GPS source (if it proves to be more accurate than the phone's)
• Message IDs and receipt confirmation
• Improve chat message shrinking further
• Smarter sending -- Map Markers get higher priority unless PLI has not gotten sent in ~5 minutes
• Smarter sending -- Send a list of map markers to group, other clients can reply with which marker they are missing, build up a list of missing markers if more than 1 person is missing send to group, otherwise send to individuals
• Needs more real-world stability testing
• Re-add GoTenna support with a proper abstraction for communication layer
• Bridge between multiple comm. devices? E.g. Meshtastic + goTenna on one device. Alternative is to break that into more than one plugin instance since their preSendProcessors will see each other's messages.
• Use Dagger 2
• Get a proper CI setup going (GitHub Actions?)

Building the Plugin

The below instructions assume that you are cloning everything side-by-side in the same directory, so you should end up with a directory tree like:

workspace/
  |
  \--- Meshtastic-Android/
  |
  \--- AndroidTacticalAssaultKit-CIV/
  |
  \--- atak-forwarder/

Set Up Meshtastic

• Flash your devices with the lastest Meshtastic Firmware (The plugin has been tested with 1.1.5 beta, if you have issues try that version)
• Install the Meshtastic App from the Play Store.
• That's all, you don't need to open the app to continue

Build + Install ATAK

ATAK requires that plugins be signed with a whitelisted signature. In order to run your own builds of the plugin you will need to have a copy of ATAK that is signed with the same key you are using to sign your plugin build.

• Clone the ATAK-CIV repo: git clone [email protected]:deptofdefense/AndroidTacticalAssaultKit-CIV.git
• Follow the commands in the .github/workflows files or the instructions in AndroidTacticalAssaultKit-CIV/BUILDING.md to build and install ATAK
  • Note: you will need to configure a signing key in the local.properties file

Build the ATAK Gradle Plugin

• Go to the AndroidTacticalAssaultKit-CIV/atak-gradle-takdev directory
• Run ./gradlew assemble

Build + Install ATAK Forwarder

• Clone the ATAK Forwarder repo: git clone [email protected]:paulmandal/atak-forwarder.git
• Copy the local.properties file that you created while you were building ATAK to the atak-forwarder directory
• Edit local.properties and add this line, remember to update the path to your correct path: sdk.path=/path/to/your/AndroidTacticalAssaultKit-CIV/atak/ATAK/app/build/libs
• Edit the app Run Configuration in atak-forwarder and set the Launch Options to Nothing
• Build the atak-forwarder plugin and install it on your devices (note: the environment variable ATAK_VERSION can be used to override the target ATAK version found in app/build.gradle)

Setting up the Plugin

Setting up your Comm Device

• In the Android Settings / Connected Devices or Bluetooth Settings tap Pair a new device
• Pair with your Meshtastic device
• Start ATAK, you should see a purple icon in the lower right corner of the screen
• Tap on the three dots menu in the upper right corner of the ATAK screen
• Tap on Settings
• Tap on Tool Preferences
• Tap on Specific Tool Preferences
• Tap on ATAK Forwarder Preferences
• Tap on Refresh Devices
• Tap on Set Comm Device and pick your device from the list
• Tap on Set Region and pick the region you are currently in
• The red line through the icon in the lower right corner of the screen should disappear within about a minute

Setting up your Channel

• In ATAK tap on the three dots menu in the upper right corner of the screen
• Tap on Settings
• Tap on Tool Preferences
• Tap on Specific Tool Preferences
• Tap on ATAK Forwarder Preferences
• Scroll to Channel Name and tap on it to set your channel name, max length is 11 characters
• Tap on Mode / Speed and pick a mode, try Short Range / Fast to start with
• Tap on Generate PSK to generate a new pre-shared key to encrypt your channel with
• Tap on Show QR to show a QR code with your channel's settings
• On your other devices, go to the same Settings screen and then tap Scan QR to scan the channel settings
  • You should see notifications about "discovery broadcasts" once all devices are on the same channel, if you do not check the channel name, hash, and try clicking Broadcast Discovery in the plugin settings menu (click the @)
  • You should soon see map markers for each of your devices

Setting up a Tracker device

The ATAK Forwarder supports configuring Meshtastic devices that have a GPS but no phone controlling them to show up on the map with a configurable callsign, team, and icon. This can be useful for retrieving relay devices or use cases that only need to output location data (e.g. animal tracking)

• Pair your extra Meshtastic devices with your phone as normal
• In ATAK tap on the three dots menu in the upper right corner of the screen
• Tap on Settings
• Tap on Tool Preferences
• Tap on Specific Tool Preferences
• Tap on ATAK Forwarder Preferences
• Scroll to Tracker and configure your Team, Role, and other settings
• Click on Write to Device and pick your device from the dropdown, set a Callsign and click OK
• You will see a small spinning progress bar appear on the screen, wait until it disappears before doing anything else with the plugin
• After the spinning progress bar disappears check the devices channel on its LCD, if the channel is updated reset the device by pressing the reset button for a second or two
• You should see your device appear on the map after it boots back up, its location should start updating once it has a GPS lock

Notes on Message Handling

Message handling follows a few simple rules:

• Messages from ATAK that are not chat are checked against a Recently Sent cache, if a message was recently sent it was dropped. This prevents spamming of auto-send map markers.

• Messages are then queued in a prioritized queue, with the priority: chat = pli > marker

• If a similar message already exists in the queue (e.g. PLI) it will be overwritten with the new message, this way a queued PLI won't be sent with out of date data if newer data is available

• This compares Lat/Lon exactly so device GPS imprecision will probably cause PLIs to get queued up, either way there should never be more than 1 PLI in the queue

• Messages are fetched from this queue by the CommHardware class and sent

• The plugin will attempt to first use a "minimal" protobuf that saves space, but if it will result in dropped fields or a failed mapping on the receiving size it will fall back to the regular protobufs

• When values appear more than once in a payload we attempt to replace subsequent appearances with a marker/placeholder that is swapped back for the value when rebuilding the original message

Contributing

Areas I'd especially like help are:

• reducing the message sizes without affecting features in ATAK (e.g. removing detail.contact.endpoint kills chat) -- check out https://github.com/paulmandal/libcotshrink for this effort
• increasing resilience of this plugin, it is basically fire-and-forget (and maybe lose your message) right now
• re-introducing goTenna Mesh support

The hardware/communication layer is (kinda) abstracted behind a CommHardware interface, this interface can be implemented against other hardware -- if you would like to give it a shot with another hardware layer please reach out to me and let me know how it goes.