# HEX/ProfiCNC Here+ RTK GPS
The Here+ RTK GPS receiver is a small, light and energy efficient RTK GPS module, based on the u-blox M8P. Using RTK, PX4 can get its position with centimetre-level accuracy, which is much more accurate than can be provided by a normal GPS.
# Purchase
- ProfiCNC
- Hex - China (China)
- Other resellers
# Configuration
RTK setup and use on PX4 via QGroundControl is largely plug and play (see RTK GPS for more information).
# Pinout
The Here+ GPS comes with an 8 pin connector with the following pinout
| Pin | Here+ GPS |
|---|---|
| 1 (purple) | VCC_5V |
| 2 (blue) | GPS_RX |
| 3 (green) | GPS_TX |
| 4 (yellow) | I2C SCL |
| 5 (orange) | I2C SDA |
| 6 (red) | SAFETY BUTTON |
| 7 (brown) | BUTTON_LED |
| 8 (black) | GND |
# Wiring and Connections
Connection examples are shown below for a number of boards (these can be used to modify the cable as needed for other boards).
# Hex Cube
The supplied cable can be inserted directly into the Hex Cube (Pixhawk 2) GPS UART port.
# Pixhawk 3 Pro
The Pixhawk 3 Pro and Pixracer have a 6 pin GPS port connector. For these controllers you can modify the GPS cable (as shown below) to remove pin 6 and 7.
Pin 6 and 7 are for the safety button - these can be attached as well if needed.
| Pin | Here+ GPS | Pin | Pixhawk 3 Pro GPS |
|---|---|---|---|
| 1 | VCC_5V | 1 | VCC |
| 2 | GPS_RX | 2 | GPS_TX |
| 3 | GPS_TX | 3 | GPS_RX |
| 4 | I2C SCL | 4 | SCL |
| 5 | I2C SDA | 5 | SDA |
| 6 | BUTTON | - | - |
| 7 | BUTTON_LED | - | - |
| 8 | GND | 6 | GND |
# Pixhawk 4
The Here+ to Pixhawk 4 GPS port pin mapping is 1:1 for pins 1-7 and then connect GND (Here+ pin 8 / Pixhawk pin 10). Pixhawk 4 GPS port pins 8 and 9 can be left disconnected.
Note The Pixhawk 4 GPS port has pin 1 on the left hand side.
| Pin | Here+ GPS | pin | Pixhawk 4 GPS Port |
|---|---|---|---|
| 1 | VCC_5V | 1 | VCC (+5V) |
| 2 | GPS_RX | 2 | GPS_TX |
| 3 | GPS_TX | 3 | GPS_RX |
| 4 | I2C SCL | 4 | SCL1 |
| 5 | I2C SDA | 5 | SDA1 |
| 6 | BUTTON | 6 | SAFETY_SWITCH |
| 7 | BUTTON_LED | 7 | SAFETY_SWITCH_LED |
| / | - | 8 | VDD_3V3 |
| / | - | 9 | BUZZER |
| 8 | GND | 10 | GND |