iOS

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There are a variety of 3rd party apps available for GIS and surveying for Android, iOS, and Windows. We will cover a few examples below that should give you an idea of how to get the incoming NMEA data into the software of your choice.

The software options for Apple iOS are much more limited because Apple products do not support Bluetooth SPP. That's ok! The SparkFun RTK products support additional connection options including TCP and Bluetooth Low Energy (BLE).

ArcGIS Field Maps

For reasons unknown, Esri removed TCP support from Field Maps for iOS and is therefore not usable by SparkFun RTK devices at this time.

If you must use iOS, checkout SW Maps, ArcGIS QuickCapture, or ArcGIS Survey123.

Field Maps for Android is supported.

ArcGIS QuickCapture

ArcGIS QuickCapture is a popular offering from Esri that works well with SparkFun RTK products.

ArcGIS QuickCapture connects to the RTK device over TCP. In other words, the RTK device needs to be connected to the same WiFi network as the device running QuickCapture. Generally, this is an iPhone or iPad operating as a hotspot.

Note: The iOS hotspot defaults to 5.5GHz. This must be changed to 2.4GHz. Please see Hotspot Settings.

The RTK device must use WiFi to connect to the iPhone or iPad. In the above image, the device will attempt to connect to iPhone (a cell phone hotspot) when WiFi is needed.

Next, the RTK device must be configured as a PVT Server. The default port of 2948 works well. See TCP/UDP Menu for more information.

Once the RTK device connects to the WiFi hotspot, its IP address can be found in the System Menu. This is the number that needs to be entered into QuickCapture. You can now proceed to the QuickCapture app to set up the software connection.

From the main screen, press the hamburger icon in the top left corner.

Press the Settings button.

Select the Location Provider option.

Select Via Network.

Enter the IP address and port previously obtained from the RTK device and click ADD.

That provider should now be shown connected.

From the main screen, click on the plus in the lower left corner and then BROWSE PROJECTS.

For this example, add the BioBlitz project.

Above, we can see the GPS accuracy is better than 1ft. Click on the map icon in the top right corner.

From the map view, we can see our location with very high accuracy. We can now begin gathering point information with millimeter accuracy.

ArcGIS Survey123

ArcGIS Survey123 Home Screen

ArcGIS Survey123 is a popular offering from Esri that works well with SparkFun RTK products.

ArcGIS Survey123 connects to the RTK device over TCP. In other words, the RTK device needs to be connected to the same WiFi network as the device running ArcGIS. Generally, this is an iPhone or iPad.

Adding WiFi network to settings

The RTK device must use WiFi to connect to the data collector. Using a cellular hotspot or cellphone is recommended. In the above image, the device will attempt to connect to iPhone (a cell phone hotspot) when WiFi is needed.

TCP Server Enabled on port 2948

Next, the RTK device must be configured as a TCP Server. The default port of 2948 works well. See TCP/UDP Menu for more information.

RTK device showing IP address

Once the RTK device connects to the WiFi hotspot, its IP address can be found in the System Menu. This is the number that needs to be entered into ArcGIS Survey123. You can now proceed to the ArcGIS Survey123 app to set up the software connection.

ArcGIS Survey123 Home Screen

From the home screen, click on the 'hamburger' icon in the upper right corner.

ArcGIS Survey123 Settings Menu

From the settings menu, click on the Settings gear.

ArcGIS Survey123 Settings List

From the settings list, click on Location.

ArcGIS Survey123 List of Location Providers

Click on the Add location provider.

ArcGIS Survey123 Network Connection Type

Select Network.

ArcGIS Survey123 TCP Connection Information

Enter the IP address previously found along with the TCP port. Once complete, click Add.

ArcGIS Survey123 Sensor Settings

You may enter various sensor-specific settings including antenna height, if desired. To view real-time sensor information, click on the satellite icon in the upper right corner.

ArcGIS Survey123 Sensor Data

The SparkFun RTK device's data should now be seen. Click on the Map icon to return to the mapping interface.

ArcGIS Survey123 Map Interface

Returning to the map view, we can now begin gathering point information with millimeter accuracy.

QField

QField is a free iOS app that runs QGIS.

Modified NMEA messages on RTK Torch

First, configure the RTK device to output only the following NMEA messages:

• GPGGA
• GPGSA
• GPGST
• GPGSV

QField currently does not correctly parse other messages such as GPRMC, or RTCM. These messages will prevent communication if they are enabled.

These NMEA message settings can be found under the Messages menu, using the web config page or the serial config interface.

Adding WiFi network to settings

Next, the RTK device must use WiFi to connect to the data collector. Using a cellular hotspot or cellphone is recommended. In the above image, the device will attempt to connect to iPhone (a cell phone hotspot) when WiFi is needed.

TCP Server Enabled on port 9000

Next, the RTK device must be configured as a TCP Server. QField uses a default port of 9000 so that is what we recommend using. See TCP/UDP Menu for more information.

RTK device showing IP address

Once the RTK device connects to the WiFi hotspot, its IP address can be found in the System Menu. This is the number that needs to be entered into QField. You can now proceed to the QField app to set up the software connection.

QField Opening Screen

Click on QFieldCloud projects to open your project that was previously created on the QField Cloud or skip this step by using one of the default projects (Bee Farming, Wastewater, etc).

QField Main Map

From the main map, click on the 'hamburger' icon in the upper left corner.

QField Settings Gear

Click on the gear to open settings.

Click on the Settings menu.

QField Positioning Menu

From the Positioning menu, click Add.

QField Entering TCP Information

Select TCP as the connection type. Enter the IP address of the RTK device and the port number. Finally, hit the small check box in the upper left corner (shown in pink above) to close the window.

Once this information is entered, QField will automatically attempt to connect to that IP and port.

QField TCP Connected

Above, we see the port is successfully connected. Exit out of all menus.

QField Connected via TCP with RTK Fix

Returning to the map view, we see an RTK Fix with 11mm positional accuracy.

SW Maps

SWMaps is available for iOS here.

Make sure your RTK device is switched on and operating in Rover mode.

Make sure Bluetooth is enabled on your iOS device Settings.

The RTK device will not appear in the OTHER DEVICES list. That is OK.

iOS Settings Bluetooth

Open SWMaps.

Open or continue a Project if desired.

SWMaps will show your approximate location based on your iOS device's location.

iOS SWMaps Initial Location

Press the 'SWMaps' icon at the top left of the screen to open the menu.

iOS SWMaps Menu

Select Bluetooth GNSS.

iOS SWMaps Bluetooth Connection

Set the Instrument Model to Generic NMEA (Bluetooth LE).

iOS SWMaps Instrument Model

Press 'Scan' and your RTK device should appear.

iOS SWMaps Bluetooth Scan

Select (tick) the RTK device and press 'Connect'.

iOS SWMaps Bluetooth Connected

Close the menu and your RTK location will be displayed on the map.

You can now use the other features of SWMaps, including the built-in NTRIP Client.

Re-open the menu and select 'NTRIP Client'.

Enter the details for your NTRIP Caster - as shown in the SWMaps section above.

iOS SWMaps NTRIP Client

Click 'Connect'

At this point, you should see a Bluetooth Pairing Request. Select 'Pair' to pair your RTK with your iOS device.

iOS Bluetooth Pairing

SWMaps will now receive NTRIP correction data from the caster and push it to your RTK over Bluetooth BLE.

From the SWMaps menu, open 'GNSS Status' to see your position, fix type and accuracy.

iOS SWMaps GNSS Status

If you return to the iOS Bluetooth Settings, you will see that your iOS and RTK devices are now paired.

iOS Settings Bluetooth - Paired

Other GIS Packages

Hopefully, these examples give you an idea of how to connect the RTK product line to most any GIS software. If there is other GIS software that you'd like to see configuration information about, please open an issue on the RTK Firmware repo and we'll add it.

What's an NTRIP Caster?

In a nutshell, it's a server that is sending out correction data every second. There are thousands of sites around the globe that calculate the perturbations in the ionosphere and troposphere that decrease the accuracy of GNSS accuracy. Once the inaccuracies are known, correction values are encoded into data packets in the RTCM format. You, the user, don't need to know how to decode or deal with RTCM, you simply need to get RTCM from a source within 10km of your location into the RTK device. The NTRIP client logs into the server (also known as the NTRIP caster) and grabs that data, every second, and sends it over Bluetooth to the RTK device.

Where do I get RTK Corrections?

Be sure to see Correction Sources.

Don't have access to an NTRIP Caster or other RTCM correction source? There are a few options.

The SparkFun RTK Facet L-Band gets corrections via an encrypted signal from geosynchronous satellites. This device gets RTK Fix without the need for a WiFi or cellular connection.

Also, you can use a 2nd RTK product operating in Base mode to provide the correction data. Check out Creating a Permanent Base.

If you're the DIY sort, you can create your own low-cost base station using an ESP32 and a ZED-F9P breakout board. Check out How to Build a DIY GNSS Reference Station.

There are services available as well. Syklark provides RTCM coverage for $49 a month (as of writing) and is extremely easy to set up and use. Point One also offers RTK NTRIP service with a free 14 day trial and easy to use front end.