# ArduSimple simpleRTK2B

The ArduSimple simpleRTK2B is the most popular low-cost RTK board, built around the **u-blox ZED-F9P** multi-band GNSS module. It tracks GPS, GLONASS, Galileo, and BeiDou on L1/L2 frequencies and delivers centimeter-level accuracy with RTK corrections. The newer simpleRTK3B uses the u-blox ZED-F9R with built-in IMU for dead reckoning. Both boards are compatible with the ArduSimple RTK Handheld kit and the RTK Calibrated Surveyor kit. This guide covers two setup methods: Bluetooth to phone (fieldwork) and direct USB to PC (bench testing).

## Requirements

* **ArduSimple simpleRTK2B** or **simpleRTK3B** board with GNSS antenna and clear sky view
* **Method A:** Smartphone with Bluetooth and the Lefebure NTRIP Client or SW Maps app (Android)
* **Method B:** Windows PC with USB cable and u-blox u-center installed
* **RTKdata.com account** with active RTK credentials (username starting with `rtk`)
* **ArduSimple Bluetooth module** (XBee socket) if using Method A

{% hint style="info" %}
Don't have an RTKdata.com account yet? [Start 30-day Free Trial](https://rtkdata.com/try-rtk-corrections-free-for-30-days/) or [View Pricing](https://rtkdata.com/pricing/)
{% endhint %}

## Method A: Bluetooth to Phone (Lefebure or SW Maps)

This is the recommended method for field use. Your phone runs the NTRIP client and forwards RTCM corrections to the F9P over Bluetooth.

{% stepper %}
{% step %}

#### Prepare the board

1. Insert the ArduSimple Bluetooth module into the **XBee socket** on the simpleRTK2B.
2. Connect your GNSS antenna to the board and place it with a clear sky view.
3. Power the board via USB or battery. The green power LED should be solid.
4. Confirm **UART2 is configured for RTCM input** at the correct baud rate. The default is **38400** for UART2. If you have changed it, use **115200** for best performance.

{% hint style="warning" %}
If UART2 is not configured to accept RTCM input, corrections from the phone will be ignored. In u-center, go to **UBX-CFG-PRT** and enable RTCM3 on UART2 input.
{% endhint %}
{% endstep %}

{% step %}

#### Pair Bluetooth on your phone

1. On your Android phone, go to **Settings > Bluetooth** and scan for devices.
2. Pair with the ArduSimple module (typically named **RTK\_GNSS** or **ArduSimple**).
3. Note the paired device name for the next step.
   {% endstep %}

{% step %}

#### Configure the NTRIP client app

Open **Lefebure NTRIP Client** or **SW Maps** and create an NTRIP profile with these settings:

{% tabs %}
{% tab title="North America" %}

* **Host (domain):** `rtk.rtkdata.com`
* **Host (IP fallback):** `13.56.117.10`
* **Port:** `2101`
* **Username / Password:** From *RTK Credentials* in the internal dashboard (not website login)
* **Mountpoint (ALL CAPS):** `AUTO` (recommended) — or `AUTO_WGS84`, `AUTO_ITRF2020`, `AUTO_ITRF2014`
  {% endtab %}

{% tab title="Europe" %}

* **Host (domain):** `eu.rtkdata.com`
* **Host (IP fallback):** `3.73.41.96`
* **Port:** `2101`
* **Username / Password:** From *RTK Credentials* in the internal dashboard (not website login)
* **Mountpoint (ALL CAPS):** `AUTO` (recommended) — or `AUTO_WGS84`, `AUTO_ITRF2020`, `AUTO_ITRF2014`
  {% endtab %}

{% tab title="Australia" %}

* **Host (domain):** `aus.rtkdata.com`

* **Host (IP fallback):** `54.206.56.130`

* **Port:** `2101`

* **Username / Password:** From *RTK Credentials* in the internal dashboard (not website login)

* **Mountpoint (ALL CAPS):** `AUTO` (recommended) — or `AUTO_WGS84`, `AUTO_ITRF2020`, `AUTO_ITRF2014`
  {% endtab %}
  {% endtabs %}

* **Send NMEA GGA to Server:** **ON** (critical — without GGA, RTKdata cannot compute corrections)

* **Receiver connection:** Select your paired ArduSimple Bluetooth device.
  {% endstep %}

{% step %}

#### Connect and verify RTK Fix

1. Tap **Connect** in the NTRIP client. The app streams RTCM corrections over Bluetooth to the F9P.
2. Monitor the solution status: **3D Fix > DGPS > Float > Fix**.
3. Once the board achieves **RTK Fix**, accuracy drops to **1-2 cm**. Convergence typically takes 30-90 seconds.
4. The **No RTK** LED on the simpleRTK2B should turn off when Fix is achieved.
   {% endstep %}
   {% endstepper %}

***

## Method B: USB to PC with u-center

This method is ideal for bench testing, firmware updates, and initial board configuration.

{% stepper %}
{% step %}

#### Connect the board to your PC

1. Plug the simpleRTK2B into your PC via USB. Windows should install the driver automatically (u-blox or FTDI).
2. Open **u-center** and select the correct COM port under **Receiver > Connection**.
3. Set the baud rate to **115200** (or **38400** if default).
4. Confirm you see satellite data in the satellite view panel.
   {% endstep %}

{% step %}

#### Enable the u-center NTRIP client

1. Go to **Receiver > NTRIP Client Settings**.
2. Enter the connection details for your region:

{% tabs %}
{% tab title="North America" %}

* **Address:** `rtk.rtkdata.com`
* **Port:** `2101`
* **Username / Password:** Your RTK credentials
* **Mountpoint:** `AUTO`
  {% endtab %}

{% tab title="Europe" %}

* **Address:** `eu.rtkdata.com`
* **Port:** `2101`
* **Username / Password:** Your RTK credentials
* **Mountpoint:** `AUTO`
  {% endtab %}

{% tab title="Australia" %}

* **Address:** `aus.rtkdata.com`
* **Port:** `2101`
* **Username / Password:** Your RTK credentials
* **Mountpoint:** `AUTO`
  {% endtab %}
  {% endtabs %}

3. Enable **Send GGA** and set the interval to **5 seconds**.
4. Click **OK** to connect.

{% hint style="danger" %}
If GGA is not being sent, you will see "0 GGA sessions" in the RTKdata dashboard and the caster will reject the connection. Always verify GGA is enabled.
{% endhint %}
{% endstep %}

{% step %}

#### Verify RTK Fix in u-center

1. Open the **Data View** panel (View > Data View). The **Fix Mode** field will show the current solution.
2. Watch the progression: **3D > DGNSS > Float > Fix**.
3. The horizontal accuracy estimate (hAcc) should drop below **0.02 m** at Fix.
4. The u-center map view will show your position converging to a stable point.
   {% endstep %}
   {% endstepper %}

## Vertical reference (heights)

{% hint style="info" %}
Heights from RTKdata.com are **ellipsoidal**, not orthometric (mean sea level). Apply a geoid model in your GIS or surveying software if MSL heights are required.
{% endhint %}

## Troubleshooting

| Problem                                   | Cause                                  | Fix                                                                                                              |
| ----------------------------------------- | -------------------------------------- | ---------------------------------------------------------------------------------------------------------------- |
| No GGA sent (0 GGA sessions on dashboard) | GGA output disabled in app or u-center | Enable **Send NMEA GGA** in Lefebure / SW Maps, or enable **Send GGA** in u-center NTRIP settings.               |
| Wrong COM port in u-center                | Multiple USB devices connected         | Open Device Manager and confirm which COM port is assigned to the u-blox or FTDI device.                         |
| UART2 not receiving corrections           | RTCM input not enabled on UART2        | In u-center, navigate to **UBX-CFG-PRT > UART2** and enable RTCM3 under Protocol In.                             |
| Mountpoint error                          | Typed in lowercase                     | Enter `AUTO` in ALL CAPS. Do not browse the mountpoint table.                                                    |
| Bluetooth pairs but no data flows         | Baud rate mismatch                     | Ensure the Bluetooth module and UART2 are both set to the same baud rate (38400 or 115200).                      |
| Slow convergence or no Fix                | Outdated firmware                      | Update the ZED-F9P firmware via u-center (**Tools > Firmware Update**). Use the latest HPG firmware from u-blox. |

## Tips and tricks

* **Update your F9P firmware first.** Newer HPG firmware versions significantly improve Fix time and multi-constellation support. Download from the u-blox website.
* **Method A is best for fieldwork** and pairs well with the ArduSimple RTK Handheld kit. Method B is best for initial configuration and bench testing.
* **Set UART2 to 115200 baud** for faster RTCM throughput, especially when using multiple constellation corrections.
* **The simpleRTK3B (F9R)** adds dead reckoning via its built-in IMU. The NTRIP setup is identical to the simpleRTK2B.
* **For the RTK Calibrated Surveyor kit**, the board comes pre-configured with correct UART settings. Skip the UART2 configuration step.
* **Log raw data** to the onboard microSD (if equipped) for PPK post-processing as a fallback when NTRIP connectivity is intermittent.