July 27, 2021

Utilizing RTK Support In Global Mapper Mobile Pro

Written by: Jeff Hatzel

 

The recent addition of Advanced GPS to Global Mapper Mobile Pro brought new and exciting functionality to the app: the ability to connect to external Bluetooth GNSS (Global National Satellite System) devices. This functionality had been highly requested from our users, and as they began to work with it, it became clear that we could expand it even further by adding support for RTK – Real-Time Kinematics, a location technique used when high precision positioning is required. RTK corrections often provide centimeter-level positions, compared to the meter-level accuracy that is common with non-RTK GNSS.

Global Mapper Mobile Pro v2.2 now supports connection to select RTK devices (see the Android and iOS documentation for complete lists of supported vendors). This allows users to utilize a new built-in NTRIP client to connect to their correction source directly in Global Mapper Mobile. The Advanced GPS information pages will now reflect that information as well.

Using the RTK functionality within Global Mapper Mobile Pro requires just a few settings to get started. The first step is to set up the NTRIP client to connect to your correction source of choice. Many states in the US have free sources, but proprietary ones are available as well. As you’ll see below, I connected to my state’s public network.

 

RTK Configuration is found under the Advanced GPS menu in the app. Entering your correction service’s credentials allows you to choose an available mount point along with viewing the relevant details. Choosing to Enable (start NTRIP on Adv GPS connect) ensures that when you connect to your external device, the correction service starts as well. Once connected to your external device, you will see a more detailed alert outlining your NTRIP status, elevation source information, and a pole height if one has been set in Configuration.

 

At this stage, you’ll be able to use the Advanced GPS information pages, which have been updated to show relevant RTK information. The Location page now shows information such as the fix type, geoid separation (if provided from your device), and, in the Status section of this page, a variety of details pertaining to communication between your device and Global Mapper Mobile Pro. 

The Satellites page has seen some updates as well. It now reflects all constellations along with fix status and SNR information. The NMEA stream, read directly from the external unit, can now be recorded in the background, allowing you to continue gathering data in the field simultaneously.

 

When working on the map and displaying GPS location information, the dialog will show the name of your connected device, along with horizontal and vertical accuracy information.

 

All location-based functionality within the app — from auto-line creation to GPS averaging — can now leverage RTK-corrected location information. This further expands the ability of professional users to confidently take Global Mapper Mobile Pro into the field for any high accuracy work they may need to conduct.

Global Mapper Mobile version 2.2 is available for download from the iOS App store and Google Play. If you would like to utilize the new RTK correction updates, consider a Pro Module subscription

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