You can connect to your external RTK GNSS Antenna via USB cable.

In this case, you will need a OTG (on the go) adapter. In this case, usually the external GNSS antenna is powerd via your Smartphone too.

Select the USB-device in RTKcamera App

Once the cables are connected, you can choose your USB device from “Device List”. 

USB Devices are shown with their mount information. But always start with the [USB] information.

If you have trouble finding your Device press “Search for Device” and it should show up among your selections. 

Settings

There are two types of USB connection available. 

• The "real" USB, where drivers and protocols are used for data transfer. 
• Or a "Serial USB" where the RX/TX connection of the gnss chip is used for data stream transfer.

Most GNSS chip have both available, so it depends on the implementation of the gnss chip on your circuit board/device. We're afraid you have to check the manual of your gnss board and/or device.

The good news, RTKcamera App tries to determine which one is yours!

1) USB Port MTP "the real usb"

In this case, data is transferred using standardised protocols. If you gnss circuit board is directly connected to USB pins of the chip this type of connection which will work for you. You can choose directly, no settings required.

Troubleshoot:

On some devices (Samsung mainly) you have to "Force USB connection". In RTKcamera App, go to "Settings > Debug Settings" and enable the option there to get a connection. 

2) USB Serial - Settings

In this case, USB cable is used as a RX / TX connection with a specific baudrate and bits. You have to set up this first to let the App know how the data is transferred.

Go to "Settings > Serial USB" and enter the settings. If you don't know, please refer to the manual of your gnss chip.

In Serial USB Settings, enter the Baudrate and check the other settings. Baudrate is usually 38400, 57600 or 115200. Rarely something other.