# Tersus Oscar / David

The Tersus Oscar and David are GNSS receivers by Tersus GNSS. The Oscar is the flagship model featuring IMU-based tilt compensation and a compact smart antenna design for professional surveying. The David is a cost-efficient, palm-sized GNSS receiver designed for surveying, UAV, and agricultural applications. Both receivers are configured through the **Tersus Nuwa** app running on an Android device or controller.

## Requirements

* **Tersus Oscar or David** powered on with clear sky visibility
* **Tersus Nuwa app** on an Android device or controller
* **Internet connection** via the controller/phone mobile data (PDA Network) or the receiver's internal SIM card (Receiver Network, if equipped)
* **RTKdata.com account** with active RTK credentials (username starting with `rtk` and password from your RTK dashboard)
* **Survey pole** with Tersus adapter

{% 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 %}

## Step-by-step setup via Tersus Nuwa

{% stepper %}
{% step %}

#### Connect to the receiver

1. Power on your Oscar or David receiver and wait for satellite tracking to begin.
2. Open the **Tersus Nuwa** app on your Android device.
3. Go to **Device** (main menu) > **Connect**.
4. Select your Tersus receiver from the Bluetooth device list and pair it.
5. Once connected, Nuwa will display the receiver model, firmware version, and satellite tracking status.
   {% endstep %}

{% step %}

#### Create a new rover configuration

1. In Nuwa, go to **Device** > **Rover** > **New** to create a new rover configuration.
2. Name it **RTKdata**.
   {% endstep %}

{% step %}

#### Select the data link and protocol

1. Set **Data Link** to one of the following:
   * **PDA Network** — uses the Android device's internet connection (phone hotspot or mobile data). This is the most common option.
   * **Receiver Network** — uses a SIM card inserted in the receiver (Oscar models with 4G modem only).
2. Set **Protocol** to **NTRIP**.

{% hint style="info" %}
**PDA Network** is recommended for most users. It uses the phone/controller's internet connection and does not require a SIM card in the receiver.
{% endhint %}
{% endstep %}

{% step %}

#### Enter RTKdata.com NTRIP settings

Fill in the NTRIP connection fields. Select the tab for your region:

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

* **IP (Host):** `rtk.rtkdata.com`
* **IP fallback:** `13.56.117.10`
* **Port:** `2101`
* **Username / Password:** From *RTK Credentials* in the internal dashboard (not website login)
* **Mount Point:** `AUTO`
  {% endtab %}

{% tab title="Europe" %}

* **IP (Host):** `eu.rtkdata.com`
* **IP fallback:** `3.73.41.96`
* **Port:** `2101`
* **Username / Password:** From *RTK Credentials* in the internal dashboard (not website login)
* **Mount Point:** `AUTO`
  {% endtab %}

{% tab title="Australia" %}

* **IP (Host):** `aus.rtkdata.com`
* **IP fallback:** `54.206.56.130`
* **Port:** `2101`
* **Username / Password:** From *RTK Credentials* in the internal dashboard (not website login)
* **Mount Point:** `AUTO`
  {% endtab %}
  {% endtabs %}

{% hint style="warning" %}
Type `AUTO` manually in all capital letters. You can also tap the **refresh icon** next to the mountpoint field to fetch the source table, but typing `AUTO` directly is faster and more reliable.
{% endhint %}
{% endstep %}

{% step %}

#### Verify GGA position sending

Nuwa automatically sends GGA position data to the NTRIP caster when connected as a rover — this is the default behavior and typically does not require manual configuration. However, verify that:

1. GGA sending is not explicitly disabled in the rover settings.
2. The rover has an initial satellite fix (even a standalone fix) before connecting to the caster, so it has a position to send.

{% hint style="danger" %}
RTKdata requires GGA position data to select the nearest base station. If the rover has no initial position fix, the caster cannot determine which corrections to send. Wait for at least an autonomous position before starting the NTRIP connection.
{% endhint %}
{% endstep %}

{% step %}

#### Start the rover

1. Tap **Confirm** to save the rover configuration.
2. Tap **Start** (or the rover will start automatically after confirming).
3. Nuwa connects to the internet, then to the RTKdata NTRIP caster.
4. Watch the solution status in the Nuwa status bar: **Single** > **Float** > **Fixed**.
5. Once Fixed, you are ready to collect points, stake out, or run your survey workflow.
   {% endstep %}
   {% endstepper %}

## Oscar tilt compensation

The Oscar features IMU-based tilt compensation. Once RTK Fix is achieved, Nuwa will prompt you to initialize the tilt sensor if needed — walk a few steps to calibrate. Initialization is typically very fast (a few seconds). You can then measure with the pole tilted without leveling.

## David receiver notes

The David is a compact, budget-friendly receiver. Key differences from the Oscar:

* **No tilt compensation** — the David does not have an integrated IMU.
* **Connectivity** — the David may rely on the controller's internet (PDA Network) rather than a built-in modem, depending on the model variant.
* **Same Nuwa workflow** — NTRIP configuration steps are identical to the Oscar.

## Compatible field software

In addition to Nuwa, Tersus receivers are compatible with:

* **SurPad** — third-party Android survey software
* **SW Maps** — free Android GIS/survey app with built-in NTRIP client
* **Carlson SurvPC** — Windows-based survey software
* **QField / QGIS** — use an external NTRIP client or Nuwa in the background

## Vertical reference (heights)

{% hint style="info" %}
Heights from RTKdata.com are **ellipsoidal**, not orthometric (mean sea level). Configure a geoid model in Nuwa under your project coordinate system settings if your project requires orthometric heights.
{% endhint %}

## Troubleshooting

| Problem                         | Cause                                          | Fix                                                                                                                            |
| ------------------------------- | ---------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------ |
| No internet connection          | Phone/controller has no data                   | Verify your Android device has mobile data or Wi-Fi connected. If using Receiver Network, check the SIM card and APN settings. |
| "Connection failed"             | Wrong host or port                             | Double-check the host address and port `2101`. Try the IP fallback address if the domain does not resolve.                     |
| Mountpoint not found            | Typo or wrong case                             | Type `AUTO` in ALL CAPS. Do not include spaces or extra characters.                                                            |
| No corrections received         | GGA not being sent                             | Ensure the rover has at least an autonomous fix before connecting. Restart the rover connection if needed.                     |
| Stuck on Float                  | Poor sky conditions or far from base           | Move to open sky. Check RTKdata base coverage at [rtkdata.com](https://rtkdata.com).                                           |
| Credentials rejected            | Using website login instead of RTK credentials | Use the username (starting with `rtk`) and password from your RTK dashboard, not your website account.                         |
| Receiver not found in Bluetooth | Bluetooth not enabled or out of range          | Enable Bluetooth on both the receiver and phone. Bring the phone within 10 meters of the receiver.                             |

## Tips and tricks

* **PDA Network is the easiest setup** — it uses your phone's internet directly without needing a SIM card in the receiver.
* **Save the rover profile** so you can reuse it across projects without re-entering NTRIP settings.
* **Oscar firmware updates** can be applied via USB or over-the-air — keep firmware updated for best RTK performance and constellation support.
* **Check correction age** in the Nuwa status bar. Values above 5 seconds indicate an unstable internet link.
* **For the David**, consider pairing with a rugged Android phone running Nuwa for a lightweight, portable RTK solution.
* **Nuwa supports RTCM 3.1/3.2 transformation messages** (1021-1027) for coordinate system transformations directly in the app.