> ## Documentation Index
> Fetch the complete documentation index at: https://docs.altnautica.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Android Client

> Use your Android phone or tablet as a ground station display.

# Android Client

Your Android phone or tablet is a client for the ground station. Join the WiFi hotspot or plug in a USB-C cable, and you have live video and telemetry on your phone. Chrome works today with no install. The ADOS Android app is in development and will add native decoding and auto-discovery; the feature notes below describe the planned client.

## Three connection paths

App latencies are targets for the in-development client. Browser figures reflect what works today.

| Path         | How it works                                                       | Latency                                    | When to use                          |
| ------------ | ------------------------------------------------------------------ | ------------------------------------------ | ------------------------------------ |
| WiFi AP      | Phone joins `ADOS-GS-XXXX`, opens the browser (or the planned app) | 80-120 ms (browser), 50-80 ms (app target) | Primary field use, no cables         |
| USB-C tether | Cable from phone to ground station, CDC-NCM Ethernet               | 40-70 ms                                   | Wired reliability, phone charges too |
| Cloud relay  | Both ends on separate internet, routed through Altnautica cloud    | 150-300 ms                                 | Remote observer, not pilot           |

## WiFi AP connection

<Steps>
  <Step title="Join the hotspot">
    Open your phone WiFi settings. Look for `ADOS-GS-XXXX`. Enter the passphrase printed on the ground station case (default for bench builds: `ados-ground`).
  </Step>

  <Step title="Handle the no-internet warning">
    Android will show a "No internet" notification because the ground station is a local network. Tap "Stay connected" or "Use without internet." The ground station is working, it just does not provide internet access.
  </Step>

  <Step title="Open the browser">
    **Chrome browser (today):** Navigate to `http://192.168.4.1:4000` (Mission Control) or `http://setup.ados.local/` (setup webapp).

    **ADOS Android app (planned):** The app will discover the ground station automatically via mDNS so video and telemetry start in a few seconds. It is not yet available as a download.
  </Step>

  <Step title="Fly">
    Pilot with touch controls (virtual sticks overlay) or pair a Bluetooth gamepad to your phone. The first device with stick input claims pilot-in-command.
  </Step>
</Steps>

## USB-C tether connection

Android 11 and later supports CDC-NCM USB Ethernet natively.

<Steps>
  <Step title="Plug in the cable">
    Connect a USB-C data cable from your phone to the ground station. Your phone shows a notification: "USB device detected. Allow ADOS Ground Station network access?"
  </Step>

  <Step title="Approve the connection">
    Tap "Allow." Android creates a USB Ethernet interface and assigns your phone the IP `192.168.7.2`.
  </Step>

  <Step title="Open the browser">
    In Chrome, navigate to `http://192.168.7.1:4000`. The planned ADOS Android app will detect the USB connection and switch to it automatically.
  </Step>
</Steps>

<Tip>
  USB-C tether may charge your phone while streaming when the hardware supports it. Power the Ground Agent from its own wall adapter or USB-C power bank for longer field sessions.
</Tip>

## ADOS Android app (planned) vs Chrome

The table below compares Chrome, which works today, with the ADOS Android app that is in development. App rows describe planned behavior.

| Feature           | ADOS Android app (planned)         | Chrome browser (today) |
| ----------------- | ---------------------------------- | ---------------------- |
| Video decode      | Native MediaCodec (hardware H.264) | WebRTC via browser     |
| Latency           | 50-80 ms                           | 80-120 ms              |
| Auto-discovery    | mDNS, automatic                    | Manual URL entry       |
| Gamepad input     | Android InputDevice API            | Web Gamepad API        |
| Touch sticks      | Native overlay                     | Web overlay            |
| Power consumption | \~1x baseline                      | \~2-3x baseline        |

Chrome is the path that works today. You do not need to install anything. Open the browser and navigate to the ground station URL.

The ADOS Android app aims to use native MediaCodec for hardware H.264 decoding, for less power draw and lower latency than the browser's WebRTC decoder. It is not yet available as a download.

## Video codec

The ground station serves H.264 high profile level 4.1 (`avc1.640029`) over WebRTC WHEP. This profile is universally supported on Android devices going back to Android 5.0.

## Android captive portal behavior

Android 11+ aggressively checks for internet on newly joined WiFi networks. If the ground station does not respond to probe URLs quickly, Android:

* Marks the network as "no internet"
* Disables automatic data routing through it
* Shows a persistent "use mobile data" notification

The ground station handles this by serving `204 No Content` responses to Google's connectivity check URLs (`connectivitycheck.gstatic.com/generate_204`) within 100 ms. This satisfies Android's probe and prevents the network from being flagged.

<Note>
  On USB tether, Android does not fire the captive portal probe. No special handling is needed.
</Note>

## Internet sharing

By default, the ground station WiFi AP is a local-only network. Your phone cannot use the ground station's internet connection (4G modem or WiFi client uplink) for background app data.

If you want your phone to have internet through the ground station, enable "Share uplink with AP clients" in the setup webapp Network page or the ground-station panel in Mission Control. Be aware that background app data will consume the ground station's data cap if it has a 4G modem.

## Bluetooth gamepad on Android

You can pair a Bluetooth gamepad to your phone. The planned ADOS Android app will receive stick inputs via the standard Android gamepad API and send them as `MANUAL_CONTROL` MAVLink messages at 50 Hz. Today, use the Web Gamepad API in Chrome as described below.

In Chrome, the Web Gamepad API works but has some restrictions:

* Use Chrome full browser, not an in-app WebView
* The site must load from `http://192.168.*` (private IP, insecure-origin permitted)
* Press any button to register the controller

## Touch fallback

When no gamepad is connected, Mission Control in Chrome shows a virtual sticks overlay on screen (the planned ADOS Android app will do the same). Two touch zones on the left and right sides of the display act as throttle/yaw and pitch/roll sticks. Not ideal for precision flying, but good enough for basic control.

## Supported Android versions

| Android version     | WiFi AP | USB-C tether             | Notes                            |
| ------------------- | ------- | ------------------------ | -------------------------------- |
| Android 14+         | Yes     | Yes (CDC-NCM native)     | Full support                     |
| Android 11-13       | Yes     | Yes (CDC-NCM native)     | Full support                     |
| Android 10          | Yes     | Partial (may need RNDIS) | Browser only, no USB auto-detect |
| Android 9 and older | Yes     | No                       | WiFi only                        |

## What is next

* [WiFi AP](/ground-agent/wifi-ap) for laptop connection details
* [USB Tether](/ground-agent/usb-tether) for the full USB-C reference
* [Setup and Pairing](/ground-agent/setup-and-pairing) for first-time setup