Carlson RT4

Carlson RT4 rugged field tablet for surveying and construction

Carlson RT4 is a rugged Windows data collector designed for professional land surveying, construction layout, stakeout and GIS fieldwork. It provides the processing power and screen size of a compact tablet while retaining the physical controls, environmental protection and survey-instrument connectivity needed for regular outdoor use.

The RT4 is particularly well suited to surveyors and construction crews using Carlson SurvPC with external GNSS receivers, robotic total stations or conventional total stations. Project information can be collected, checked and edited directly in the field, helping reduce the amount of manual data handling required between the site and office.

Designed for Carlson SurvPC field workflows

Carlson developed the RT4 around its Windows-based SurvPC field software. This makes the tablet suitable for workflows such as topographic surveying, RTK GNSS measurement, construction stakeout, coordinate geometry, surface stakeout and total station data collection when the appropriate SurvPC modules and survey instruments are used.

For a land surveyor, the RT4 can act as the main controller connected to a GNSS rover or total station. A construction crew can use the same type of setup to stake points, lines, offsets and design elevations. GIS users can also use the Windows environment for field mapping and attribute collection.

Because the controller runs Windows rather than a restricted embedded operating system, project files can also be reviewed and managed with familiar desktop-style tools while still on site.

7 inch display for drawings maps and survey information

The RT4 uses a 7-inch 1280 × 800 display, providing considerably more working area than a traditional handheld survey controller. This is useful when viewing CAD drawings, maps, surfaces and graphical stakeout information in SurvPC.

The optically bonded high-visibility display is designed for outdoor viewing and uses chemically strengthened Dragontrail glass for additional resistance to impact and scratching. The touchscreen supports finger and small-tip stylus input and can be configured for different field conditions.

Carlson’s user manual provides dedicated touchscreen profiles for normal finger use, stylus operation, gloves and wet conditions. This gives crews more practical control when the weather or required PPE makes an ordinary consumer touchscreen difficult to operate.

Physical keys for field operation

A touchscreen is useful for working with drawings, but survey work often benefits from physical controls. The RT4 includes illuminated hardware keys, a four-way navigation pad and programmable function buttons alongside the touchscreen.

These controls can make common operations easier when the tablet is mounted on a survey pole or when the operator is wearing gloves. Programmable keys can also provide quicker access to frequently used functions rather than requiring every command to be selected from the screen.

Connect to RTK GNSS receivers and total stations

Long-range Bluetooth is one of the most important features of the Carlson RT4 for survey work. It allows the controller to communicate wirelessly with compatible GNSS receivers, robotic total stations and other surveying equipment supported by the field software.

This is particularly useful for robotic total station work, where the operator and controller move away from the instrument during one-person surveying or stakeout. For RTK GNSS, Bluetooth provides the data connection between the field controller and a compatible external rover receiver.

Wi-Fi and USB are also available for project transfer, peripheral connections and other field or office tasks. CELL configurations add 4G LTE hardware for workflows that require mobile internet connectivity.

Mobile internet for network RTK workflows

The CELL and GEO/CELL versions add integrated cellular connectivity. For surveyors using network RTK corrections, an internet connection can allow compatible SurvPC and GNSS configurations to connect to an NTRIP or other correction service without relying on a separate phone hotspot.

This can simplify a rover setup where the controller is used for both communication with the GNSS receiver and access to the correction network. Actual correction-service compatibility and availability depend on the connected receiver, software configuration, mobile network and correction provider.

Optional integrated GNSS for mapping and general positioning

GEO versions of the RT4 include an integrated 72-channel u-blox GNSS receiver and antenna. Carlson specifies typical standalone positioning accuracy of approximately 2 to 5 metres and support for real-time SBAS corrections such as EGNOS.

This integrated receiver is useful for general navigation, GIS mapping, geotagging photographs and other tasks where metre-level positioning is sufficient. It should not be confused with a survey-grade centimetre-level RTK receiver.

For cadastral surveying, precise construction stakeout and other high-accuracy work, the RT4 is normally used as the controller connected to an appropriate external RTK GNSS receiver or total station.

Built for rain dust and demanding construction sites

Consumer tablets are convenient in an office but can be vulnerable to dust, water and accidental drops. The Carlson RT4 was developed specifically for professional field conditions.

Its housing carries an IP68 rating for water and dust protection and is designed around MIL-STD-810G environmental test procedures. Carlson also specifies resistance to multiple drops onto concrete, together with impact-absorbing external bumpers.

The specified operating-temperature range is -20°C to 50°C, allowing the controller to be used across a wide range of surveying and construction environments. These characteristics make it suitable for crews working around earthmoving equipment, roads, utilities and undeveloped sites where ordinary office electronics may not be practical.

All day removable battery

The RT4 uses a removable 43.2 Wh lithium-ion battery with a specified operating time of approximately 12 to 15 hours on one charge. Actual runtime will depend on screen brightness, wireless communications, connected peripherals and the applications being used.

The removable design is useful for crews that work extended shifts or travel between remote sites. A discharged battery can be exchanged instead of waiting for the complete controller to recharge.

Carlson also designed the battery system for operation in cold field conditions, making the RT4 more appropriate for professional outdoor work than tablets intended primarily for indoor use.

Windows 10 with 8 GB RAM

The original Carlson RT4 uses Microsoft Windows 10 and a quad-core Intel Pentium N4200 processor with 8 GB of RAM. Storage configurations include 128 GB and, depending on version, 256 GB options, with a user-accessible MicroSDXC slot for additional storage.

For field crews this provides enough computing capability to run SurvPC while handling drawings, coordinate files and survey information directly on the controller. The Windows environment also allows the RT4 to be used for compatible Carlson office applications when required.

This can be useful for surveyors travelling between projects who want to perform basic file preparation, checking or data management without immediately returning to an office workstation.

Useful for land surveying

For land surveyors, the RT4 provides a large-screen controller for GNSS and total station measurement. Coordinate information, descriptions, linework and drawings can be viewed while measurements are being collected rather than relying on a separate field sketch.

When paired with a suitable RTK GNSS receiver, it can support centimetre-level field workflows through SurvPC. When connected to a robotic or conventional total station, the same controller can be used for optical surveying and setting out.

This flexibility is particularly useful for companies that use several types or brands of surveying instruments but want field crews to work with a consistent Carlson software interface.

Useful for construction layout and stakeout

Construction teams can use the RT4 to take design coordinates from the office into the field and stake them using connected surveying equipment. Foundations, utilities, kerbs, roads, building corners and other design features can be located from digital project information.

The large screen is useful when field staff need visual context from a CAD drawing rather than working from point numbers alone. Crews can see the surrounding project geometry while navigating to the required stakeout position.

For surveyors supporting machine-control or site-grading operations, the controller can also provide a practical connection between office-prepared design information and field verification measurements.

Useful for GIS and asset mapping

The RT4 is also suitable for GIS fieldwork where a rugged Windows controller is preferred. The GEO version’s internal GNSS can provide metre-level positioning for general mapping, while an external GNSS receiver can be used where the project requires greater accuracy.

Typical applications include mapping utilities, street furniture, environmental features, construction assets and other objects that need a geographic location together with descriptive field information.

The integrated camera available on applicable models can also support geotagged field photographs, giving GIS teams another way to document the condition or identity of mapped features.

STANDARD CELL and GEO CELL configurations

The Carlson RT4 was offered in several configurations so users could select the hardware required for their work. The STANDARD configuration provides the main tablet and wireless survey-controller functionality. CELL adds cellular communication, while GEO/CELL combines cellular hardware with the integrated GNSS receiver.

The correct version depends on how the controller will be used. A surveyor working exclusively with an external RTK receiver may not need an internal GNSS board, while a GIS user may benefit from integrated positioning. Network RTK users may prefer built-in cellular connectivity where supported.

Carlson RT4 or Carlson RT4 Plus

The product on this page is the original Carlson RT4. Carlson subsequently introduced the RT4+, which uses newer hardware including Windows 11, a faster Intel processor, 16 GB RAM and 256 GB storage.

This distinction is important when selecting accessories, comparing specifications or planning software deployment. Existing RT4 units remain useful as rugged SurvPC controllers, but buyers comparing new hardware should check which RT4 generation is being supplied and whether its operating system and performance match the intended software workflow.

Carlson RT4 from Global GPS Systems

Global GPS Systems can help determine which Carlson RT4 configuration is appropriate for your surveying, construction or GIS workflow and whether the controller will communicate correctly with the GNSS receiver or total station you intend to use.

For customers building a complete RTK setup, Global GPS Systems can also help match the data collector with compatible GNSS hardware, Carlson SurvPC and the correction method used in the field. This is especially important when deciding whether integrated cellular connectivity or internal GNSS is useful for the way your crews actually work.