Setup & Getting Started
User Guide

Plug and Play Installation

In this section of the manual, we will cover the basic setup of the units. To setup the GPS units you will need Mission Planner installed on your computer & ArduPilot V4.03 or later installed on your flight controller.
If you are using PX4 firmware and QGroundControl ground station software, please refer to the link for more information: https://docs.px4.io/en/advanced_features/rtk-gps.html

Before you start

Make sure you have the following pieces handy before you start this process:
  • H-RTK M8P Rover Lite and H-RTK M8P Helical or H-RTK M8P Base
  • A compatible Pixhawk flight controller (HolyBro Pixhawk Series or Holybro Durandal is recommended)
  • A configured telemetry radio set so the GPS data can be continually sent to and from the flight controller while flying
  • A laptop computer
Connect both the ground station GPS unit (H-RTK M8P Helical or H-RTK M8P Base) and the telemetry radio to your laptop using the supplied USB cables.
On the UAV side connect the H-RTK M8P Rover Lite to the GPS port on your flight controller using the 10 pin connector cable. Connect another telemetry radio to the TELEM1 interface of the flight controller. Be aware that older Pixhawk flight controllers may have different connector type.
Before you start the setup, make sure both units have a good view of the sky so they can receive the best signal from the GPS satellites.

Basic configuration

For this step Mission Planner needs to be installed and running on your Laptop (https://ardupilot.org/planner/). Note that the Pixhawk/Durandal flight controller and attached H- RTK M8P Rover Lite GPS unit do not need to be powered when the base unit is being configured.
Open Mission Planner and go to Optional Hardware and select the RTK/GPS Inject tab.
Check the box for Inject MSG Type, Send GCA, M8P/F9P Autoconfig and M8P FW 130+/F9P.
Select the correct base module com port in the top left corner and click connect. In the SurveyIn Acc section, enter the absolute geographic accuracy that you expect your H-RTK M8P base station to achieve. In the Time column, enter the minimum survey time you expect. Click on Restart, the ground station will transfer the data you have entered to the H-RTK M8P base module and the base module will start a new round of surveying for GPS satellites.
As part of the search, the box on the right side of the Mission Planner displays the current star search position. Below are some of the status messages you may see:
  • Position is invalid: the base station has not been effectively positioned yet
  • Duration: the number of seconds in which a star search has been performed
  • Observation: Number of observations obtained
  • Current Acc: Absolute geographic accuracy that the base station is able to achieve
The green bar below the Mission Planner shows the current satellite search and satellite signal strength.
The GPS base station will need some time to find enough GPS satellites to achieve the level of accuracy you selected, less accuracy requires less GPS satellites. With a good view of the sky, it can take several minutes to achieve the absolute accuracy of 2m, about an hour to achieve the absolute accuracy of 30cm, and several hours to achieve the accuracy of 10cm.
It should be noted that the absolute geographic accuracy of the base station here will affect the absolute geographic accuracy of the mobile station (as they act as a pair) but will not affect the relative accuracy of the base station and Rover module. If you don’t need the higher accuracy, then do not set it as this will dramatically increase the time taken for the system to establish a GPS lock of sufficient quality. Note that even if the accuracy of the base station is 1.5m to 2m, the position accuracy of Rover module relative to the base station can still reach centimeter level.
After the star search for H-RTK M8P Base station is completed, the Mission Planner will display the following page:
The indicator statuses should look like this. All green. This shows status of base station (BASE) is ready, along with GPS and GLONASS satellite systems.
When your screen looks like this, store the Current location on Mission Planner: Click Save Current Pos, before opening the plan.
Enter a name in the box for the save and click OK. In the following figure, you can see where you stored in the list. You can now select this location using this saved file.
With the Use button corresponding to the stored location, the base station will enter the fixed-point mode and display the status in the box on the right. When you set the base station at the same location in the future, you don't need to search again; just click on your Saved location the Use button corresponding to the location to load the location data.
After the base station is set up, you can turn on the UAV.

Using Mission Planner to connect to the UAV via telemetry radios

The RTCM GPS data of the base station will be transferred to the H-RTK M8P Rover Lite module on the UAV through the telemetry radios.
On the Mission Planner's main page, you can see that the current GPS status of the UAV is shown as RTK Float/RTK Fixed/3D RTK (as shown above), showing that the positioning of the UAV has entered the RTK status.
RTK Float is a floating-point solution, and RTK Fixed is a fixed solution. RTK Fixed has a higher accuracy and only available then the signal is good enough. 3D RTK is the uniform display mode of RTK Float/RTK Fixed for the Chinese version of Mission Planner. Refer to the latest Mission Planner documentation for the latest updates.
TIP: If you use F9P Base and Rover, the orange RTK FIX led on F9P Rover Lite module will blink when receiving RTCM data. And the RTK FIX led will stay on when the Rover module has entered the RTK status.
Congratulations, you successfully have setup the Holybro H-RTK GPS system!

Updating your GPS units

This step is optional but highly recommend for the optimum performance of your new Holybro GPS products. To update your GPS units, you will need to download and use the free u-Center software. Use at least version is V19.03.
To download u-Center, please go to the official website at https://www.u- blox.com/en/product/u-center-Windows then follow the prompts to install the U-Center software onto your computer. During installation, you will be prompted to install a windows driver. Make sure that only ‘Standard Driver for Windows’ is checked, as shown below.

Downloading the firmware for the GPS Units

The default firmware version of the H-M8P module is the firmware version of Ublox-1.40. This version of firmware supports other satellite systems (Glonass/ Beidou) and GPS fusion for RTK computing that increases the performance of RTK positioning. Version 1.40 also supports the function of mobile base stations, that is, base stations do not need to be fixed in one place, but can be moved whenever they are in use. If a new firmware version of Ublox is available, it is recommended that all users upgrade to the latest version of the firmware before using the H- M8P module.
Before the firmware update, download NEO - M8P - FW301 - HPG140_RNwithFW. Zip from Ublox website to download firmware 1.40: https://www.u-blox.com/en/product/neo-m8p- series#tab-documentation-resources
When downloaded unzip the NEO - M8P - FW301 - HPG140_RNwithFW. Zip file and save the DO_EXT_301_HPG_140_REFERENCE. Ab799cc302b64f28ba73b55dfa945a04. Bin file.

Uploading the new Firmware

To upgrade the base station module, connect the base station module to the COMPUTER using a USB cable. To update the H-RTK M8P Rover Lite module, you need to connect the module to the USB-UART small board, and the small board is then connected to the computer. As shown in the figure below:
Open u-Center software, click the connect button (in the red circle as shown below), and select the corresponding COM port for your GPS unit
Select tools-> Firmware Update and check the corresponding options in the diagram.
Uninstall and select the Firmware you downloaded in the above step. For the base station use:
DO_EXT_301_HPG_140_REFERENCE.ab799cc302b64f28ba73b55dfa945a04.bin For the H-RTK M8P Rover use:
DO_EXT_301_HPG_140_ROVER.91bbd17d889e0fe40c2d823991595224.bin
In the Flash Information Structure (FIS) File, select Flash.xml, which is located in the u-Center installation directory
Under, u-center_v19.03 select flash.xml.
Click OK and wait for the firmware to upload to the GPS. It usually takes less than a minute to flash. If the writing of the file is successful, then the upgrade interface status is displayed in green.

Confirming the version of the newly loaded firmware

Once the upload is complete you can confirm the updated version of the firmware on the module.
With the base station/mobile station connected to u-center, click the View option to enter Message view-> UBX-> MON-> VER, the interface is as shown below:
As shown in the figure, the current firmware version is FWVER=HPG 1.40 REF, indicating that the current firmware version is 1.40 base station version.
Success!

Using U-Center for Real Time Recording and Playback

U-Center can record the data of the currently connected GNSS module for later analysis and use.
To do this make sure that the GNSS module is connected to U-Center (the connection mode is the same as the upgrade process above), click the bug icon below to open the Debug Message:
Then, click enter view-> message view-> UBX-> RXM-> RTCM input status, and right-click to enable message.
Click the red record icon in the upper left corner of the interface (as shown), select an address to save the recorded content and click on OK to start the recording. Select STOP when you no longer want to record the data.
To play the recorded data, click the green play icon, select play speed, and select save in the specified file, you can start playing.

Using U-Center for diagnostics

You can also use the more advanced features of the U-Center software to see how the GPS units are performing and working. This can be especially useful for troubleshooting.
To do this, connect the base station to the U-Center software, and check whether the Fix Mode column is displayed as TIME in the box in the upper right corner of the software interface.
In Fix mode the screen will display all of the statuses of your GPS unit including the position, accuracy and HDOP details. In the figure below, Fix Mode is displayed as 3D Mode, so it has not yet reached the RTK standard needed for more accuracy.
There are a number of common reasons for the base station not entering TIME Mode:

The signal received by the base station is not strong enough.

Check the current star search signal of the base station and view the dialog box at the bottom right corner of the software interface. The bar in the dialog box represents the current satellite received by the base station, and one bar represents a satellite (GPS or Beidou /GLONASS, depending on the navigation system you choose to receive). The requirements for the base station to enter TIME Mode are as follows: 5 GPS satellite signals +2 GLONASS satellite signals with a strength above 40; Or 5 GPS satellite signals +3 Beidou satellite signals above 40. In the figure below, if only one satellite has a strength higher than 40, the signal condition fails to meet the RTK standard.
Try repositioning the GPS unit to get a clearer view of the sky.

The star searching precision of survey-IN set in advance is too strict, or the base station has not completed the star searching process.

Use U-Center to set up the specific survey-in. See the following section for more detail on common errors, issues, and tips for operation.

Check whether Rover module receives base station data (Timeout)

After the base station enters TIME Mode, RTCM data needs to be transmitted to the Rover module before the Rover module can enter RTK Mode. Therefore, the real-time and efficient data transmission of Rover module and base station is an important part to ensure the system is ready.
Check whether there is delay in data transmission between the Rover module and the base station and connect the Rover module to U-Centre (or read the previously stored log of the Rover module). Enter the Messages view-> nmea-> GxGGA directory and observe the Age of DGNSS Corr parameter parameters. This parameter represents the time when the Rover module has not received the base station data. In the case of the default base station extinction transmission frequency of 1HZ, if this parameter exceeds 1s, it means that the data transmission has a certain delay. Check your telemetry radio setup as a first step.

Set the base station as star search mode/fixed mode

Similar to the page used by RTK in The Mission Planner, the time and accuracy of star searching by base station can also be set in u-Centre. Enter the Messages View option, UBX CGF menu, and enter the TMODE3 TAB for setting. Select Survey-in in the Mode dropdown option, and then set the time of star search (and the minimum time required by base station for star search), as well as the absolute precision to be achieved when star search is completed. The higher the
absolute accuracy of the base station, the longer the star search time will take. The data of star search and location of base station can be viewed in the nav-> SVIN page in Message View.
The base station can also be set to fixed-point mode. When the current precise geographic coordinates of the base station are known you can manually input those into the base station.
This can be used instead of waiting for the base station GPS to establish a lock of sufficient accuracy. You only need to change the Mode to Fixed Mode on the TMODE3 tab, and then enter the known base station location as shown below.
After setting the star search and fixed-point mode, please click the Send button at the bottom left of the page to transfer the modified data to the base station.

Changing the GPS satellite systems (GPS+GLONASS)

By default, the uBlox 1.30 firmware uses the GPS+GLONASS navigation system for location services. If you want to change to GPS+ Beidou navigation system, then you need to enter Messages view-> Cancel the Enable option, and then check Beidou's Enable option. After selecting, click Send to store the changes.
To make sure the current settings are saved, go to the Messages view -> UBX -> CFG (Configuration) page and click Save Current Configuration option, then click Send (as shown below).
Note: The base station and Rover module must have the same Settings and use the same navigation system configuration; otherwise, the system will not be able to use RTK.

Base station input/output ports and protocol Settings problems

The uBlox M8P chip supports a variety of input and output protocols, including USB, UART, I2C, and more. H-RTK base station module USES USB protocol for data communication by default and gets and outputs RTK data.
If the current setting needs to be confirmed, enter the Messages view-> UBX-> CGF-> PRT directory to set it and select USB in the target column. The correct input and output protocols are shown in the figure below:
You can select the type of output you want and the protocol you want on this page.
In addition to these settings, you can also set a specific string of messages to be output under multiple protocols. To set this up, enter Messages view-> ubx-> cgf-> MSG directory, select a specific message, and then check the type of protocol you want to use.
To ensure that the current Settings have been saved, go to the Messages view - > ubx-> CFG (Configuration) page, click Save Current Configuration option, and then click Send.

Change the output frequency of mobile station

In the default frequency of position information output by Rover module is 1HZ. If you need to speed up the position output frequency, you can enter the Messages view -> ubx -> cgf-> RATE setting and change the Measurement Period. For example, change the Measurement Period to 200ms and the Measurement output Frequency will rise to 5HZ.
To make sure the current Settings are saved, go to the Messages view -- > ubx-> CFG (Configuration) page and click Save Current Configuration option, and then click Send.
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On this page
Plug and Play Installation
Before you start
Basic configuration
Using Mission Planner to connect to the UAV via telemetry radios
Updating your GPS units
Downloading the firmware for the GPS Units
Uploading the new Firmware
Confirming the version of the newly loaded firmware
Using U-Center for Real Time Recording and Playback
Using U-Center for diagnostics