Alpha 4i RTK GNSS Rover Set with IMU and Controller

Complete RTK GNSS Rover Set for Professional Fieldwork

The Alpha 4i Rover Set provides the main equipment needed for network RTK surveying in one practical field package. It combines the compact Alpha 4i GNSS receiver with a data collector, DiMap Pro surveying software, a telescopic survey pole and a controller bracket. This gives surveyors, construction crews, GIS technicians and engineering teams a coordinated system for measuring points, setting out designs and managing survey data on site.

The set is particularly suitable for professionals who want a lightweight rover that can connect to an NTRIP correction network through the data collector. It can also receive corrections through its internal UHF radio when used with a compatible local base station. The receiver does not contain an integrated mobile modem, so internet-based RTK corrections are normally provided through the connected controller or another compatible Android device.

Compact Receiver for Long Days in the Field

The Alpha 4i receiver measures approximately 98 mm by 53 mm and weighs only 380 g. Its small size reduces the weight carried at the top of the survey pole, which can make a noticeable difference during long topographic surveys, construction layout work and GIS data-collection projects involving hundreds of measurements.

The housing combines an aluminium-alloy reinforced structure with a signal-transparent top cover. It is rated IP67 for resistance to dust and temporary water exposure and is specified to withstand a 1.5 m drop under stated test conditions. This makes the receiver suitable for regular use on construction sites, roads, utility projects and other demanding outdoor environments.

Multi-Constellation GNSS Signal Tracking

The Alpha 4i uses 1,408 channels to track GPS, GLONASS, Galileo, BeiDou, QZSS, SBAS and NavIC signals across multiple frequencies. Tracking several satellite systems gives the receiver access to more available satellites throughout the working day.

In practical fieldwork, increased satellite availability can help the receiver maintain a more stable solution when part of the sky is obstructed by buildings, trees, machinery or surrounding terrain. The integrated full-frequency antenna uses a compact multi-feed design intended to provide dependable tracking without the bulk of a traditional large GNSS antenna.

Centimetre-Level RTK Measurements

Under suitable operating conditions, the receiver is specified for horizontal RTK accuracy of ±(8 + 1 ppm) mm and vertical accuracy of ±(15 + 1 ppm) mm. This performance is appropriate for common survey-grade work such as topographic measurement, construction setting out, road and utility surveys, control checks, earthwork verification and ground control point collection for drone mapping.

Actual results depend on satellite geometry, correction quality, baseline distance, mobile or radio coverage, nearby obstructions, multipath and correct field procedures. Operators should always check the RTK fix status, reported precision and site control before accepting an important measurement.

IMU Tilt Compensation for Difficult Points

The integrated IMU allows the pole to be tilted while collecting a point. This reduces the need to level the pole carefully at every measurement and makes it easier to reach positions beside walls, fences, kerbs, excavations, vegetation and other obstacles.

The IMU supports a wide operating range and updates at 100 Hz, allowing it to react quickly as the pole moves. For normal site work, this can create a smoother measuring workflow and reduce repeated attempts to place the pole directly above a point. Tilt compensation is especially useful during detail surveys, GIS asset collection and construction layout where access is often restricted.

Network RTK and UHF Correction Options

For network RTK surveying, the receiver connects by Bluetooth to the included data collector or a compatible Android device running field software. The controller can then provide access to an NTRIP correction service through its mobile internet connection. This configuration is useful for crews working within an established RTK network because it removes the need to set up a local base station at each project.

The Alpha 4i also contains a 1 W UHF transceiver operating across the 410–470 MHz frequency range. It supports several commonly used RTK radio protocols and can receive corrections from a compatible base receiver. The specified local radio range is up to approximately 3 km in suitable open conditions, although real working range depends heavily on terrain, antenna height, interference and local radio regulations.

DiMap Pro Surveying Software

DiMap Pro provides the field interface for receiver configuration, point measurement, stakeout and data management. The software supports base and rover setup, basemap display, point databases, stakeout record management and CAD-based fieldwork. Survey data can be exported in commonly used formats such as CSV, DXF and KML for further processing in CAD, GIS and office software.

This combination gives the rover set a practical workflow from the first measurement through to office delivery. Construction teams can load design information for stakeout, surveyors can collect and code detail points, and GIS users can record asset locations and attributes directly in the field.

Suitable Applications

• Topographic and detail surveying
• Construction layout and stakeout
• Road, utility and infrastructure surveys
• GIS asset and feature collection
• Earthwork and elevation checks
• Ground control points for drone mapping
• Boundary and cadastral support work where local regulations allow

Included Rover Equipment

The Alpha 4i Rover Set is supplied as a coordinated field package rather than a receiver-only product. The standard configuration includes the Alpha 4i GNSS receiver, UHF antenna, charging and data accessories, Alpha B55 data collector, DiMap Pro software, telescopic survey pole, controller bracket, documentation and carrying equipment. Exact accessories can be adjusted to suit the required controller, pole or field workflow.

Choosing the Right RTK Configuration

This rover set is a strong option for users who mainly work with an NTRIP correction network or already have access to a compatible GNSS base station. Buyers who need an independent two-receiver system for sites without network corrections should consider a complete rover and base configuration instead.

Global GPS Systems can help determine whether the Alpha 4i Rover Set matches the available correction service, regional radio frequencies, preferred field software and required accessories. This helps construction companies, survey businesses and GIS teams select a configuration that fits their actual work rather than paying for equipment they do not need.