# CUAV C-RTK

The [CUAV C-RTK GPS receiver](https://www.cuav.net/en/c_rtk_9ps/) is an [RTK GPS module](../gps_compass/rtk_gps.md) for the mass market.
一个完整的RTK 系统由至少两个 c-rtk 模块 组成(一个用于基站, 另外一个作为移动站用于飞机上)。 使用RTK，PX4控制器可以获取到它的位置，并且这个位置的精度可以达到厘米级的精度，这比普通GPS提供的位置更加精确。

<img src="../../assets/hardware/gps/rtk_c-rtk.jpg" width="500px" title="C-RTK" />

## 购买渠道

- [cuav taobao](https://item.taobao.com/item.htm?id=565380634341&spm=2014.21600712.0.0)
- [cuav aliexpress](https://www.aliexpress.com/store/product/CUAV-NEW-Flight-Controller-GPS-C-RTK-differential-positioning-navigation-module-GPS-for-PIX4-Pixhawk-pixhack/3257035_32853894248.html?spm=2114.12010608.0.0.75592fadQKPPEn)

## 配置

RTK setup and use on PX4 via _QGroundControl_ is largely plug and play \(see [RTK GPS](../gps_compass/rtk_gps.md) for more information\).

## 接线和连接

C-RTK GPS comes with a cable that terminates in a 6-pin connector and 4-pin connector that are compatible with [Pixhack v3](https://doc.cuav.net/flight-controller/pixhack/en/quick-start-pixhack-v3x.html#gps--compass).
6针连接器提供 rtk gps 的接口, 并应连接到飞行控制器的 gps 接口。
4针连接器是一个 m8n (标准) gps 接口, 可作为第二个 gps(可选)。

:::tip
At time of writing PX4 does not yet fully support a second GPS. The 4-pin port need not be connected.
:::

<img src="../../assets/hardware/gps/rtk_cuav_c-rtk_to_6pin_connector.jpg" width="500px" title="C-RTK_6PIN" />

The cables/connectors may need to be modified in order to connect to other flight controller boards. The pin mappings for _Pixhawk 3 Pro_ and _Pixracer_ are shown below.

### 针脚定义

The C-RTK GPS pinout is provided below. This can be used to help modify the connector for other autopilot boards.

| 引脚 | C-RTK GPS 6P                | 引脚 | Pixhawk 3 Pro GPS           | C-RTK GPS 4P                |
| -- | --------------------------- | -- | --------------------------- | --------------------------- |
| 1  | SDA                         | 1  | VCC                         |                             |
| 2  | SCL                         | 2  | GPS_TX |                             |
| 3  | GPS_RX | 3  | GPS_RX | GPS_RX |
| 4  | GPS_TX | 4  | SCL                         | GPS_TX |
| 5  | VCC_5V | 5  | SDA                         | VCC_5v |
| 6  | GND                         | 6  | GND                         | GND                         |