Here+ RTK GNSS
The Here+ RTK GNSS kit is supported by Ardupilot out of the box. It consists of a ‘rover’ designed to be mounted on the drone and is connected to the flight controller using the supplied 8‑pin JST GH connector (for the Pixhawk 2.1) or an optional 4pin+6pin DF13 connector (for the Pixhawk 1).
The base station with its smaller GNSS receiver and an external antenna complete the equipment. Embedded in the Here+ is the u‑blox NEO‑M8P module series. It is the smallest, lightest and most energy‑efficient high precision GNSS Real Time Kinematics (RTK) module available on the market, bringing centimetre‑level positioning accuracy to the mass market.
The Here+ RTK GNSS is a new product, like all new products improvements are made to features and performance after release by way of firmware updates.
Software, drivers and firmware
Install ublox u-centre, the software from the manufacturer features a firmware updater.
u-centre found here
Download the firmware here
On the above mentioned page you will find all the resources for the M8P, you may need to install the drivers and VCP manually. Check your windows settings if you are having connection problem, sometimes user account restrictions stop the installation or effect driver installs.
To manually find the files visit the ublox website > support > product resources. select the product.
Updating the Base
Using the supplied USB cable connect the base to your PC
Open u-centre and navigate to > tools > Firmware updater (ctrl+u shortcut)
A window appears as shown to the right, select the firmware (with REFERANCE in the title for base)
The FIS (flash information structure) is needed for box 3, this is located in the installed u-centre directory, usually c: > Programme files > ublox > ucentre
Success = Green!
If the firmware has successfully loaded the output screen will be green, as shown.
If you are seeing a red screen check the following;
Is it connected – com settings, driver, USB cable and connection to base
Updating the Rover
In order to connect the Rover to a PC the cover must be removed to expose the connector.
Remove all (3) screws from the reat with the provided Allen key.
Shown to the left is to connector to which the USB cable of the base can be connected.
The Here+ rover needs power to be updated, this is provided from the Pixhawk, Pixhawk can be powered via the power brick or its USB.
There is a method of updating the Here+ using mission planner via pass through, this method is not advised.
As with the base access the firmware update screen from u-centre
Select the Rover firmware file and FIS
Green = success
Connecting the Here+ to your Pixhawk
Setting up the Base
If you don’t use the base, or you lose connection with the base the rover simply reverts to the performance of the standard Here (M8N).
You can connect multiple GPS units to Pixhawk flight controllers, you should use the same type of GPS when using multiple GPS. You have 2 options for how the GPS are used, blended and switch.
Blended, as the name suggests uses a mixture of position data giving you a blended position.
Switch, uses the GPS with the strongest satellite lock or highest number of satellites.