Spherefix SP35 RTK GNSS Rover Base Set with Laser and AR Stakeout

A Complete Local RTK Rover and Base Solution

The Spherefix SP35 Rover Base Set gives field teams the equipment required to create their own local RTK correction setup. One SP35 receiver operates as the base station while the second SP35 is used as the rover. The included C100T Android controller manages survey projects, receiver settings, point collection and stakeout in the field.

This configuration is particularly useful on sites where a mobile RTK correction network is unavailable, unreliable or unsuitable for the project. It can also give surveyors greater control over the correction source, radio connection and working area. The system is suited to land surveying, construction layout, civil engineering, utility work, GIS collection, earthworks and drone mapping.

How the Rover and Base Setup Works

The base receiver is positioned over a known control point or a project position established by the surveyor. It continuously compares its known coordinates with the satellite measurements it receives and calculates correction data. These corrections are transmitted by radio to the rover, which applies them to its own GNSS observations in real time.

Using a local base can be practical on remote projects, large construction sites, agricultural land, quarries, roadworks and infrastructure projects where internet coverage is limited. It is also useful when a team wants to work independently of a subscription-based correction network. Correct base coordinates, antenna heights and coordinate-system settings remain essential because any error entered at the base will also affect the rover results.

Integrated Radio for Local RTK Corrections

Each SP35 includes a 410–470 MHz UHF and LoRa radio with selectable 0.5 W and 1.5 W transmission power. The base can therefore broadcast corrections directly to the rover without relying on mobile internet between the two receivers.

Actual radio performance depends on terrain, antenna height, surrounding buildings, vegetation, interference and local radio regulations. Positioning the base in an open and elevated location normally provides better communication than placing it behind machinery, buildings or other obstructions.

The SP35 also includes 4G, Wi-Fi, Bluetooth and NFC. This means the receiver can be configured for local radio work, network RTK operation or a combination of both, depending on the available infrastructure and project requirements.

Camera-Assisted Laser Point Measurement

The rover includes an integrated camera and laser module for measuring points that cannot be occupied directly with a survey pole. This can help when collecting building corners, trench edges, façades, walls, stockpiles, utility features, fenced assets and other points that are obstructed or unsafe to approach.

The operator aims at the required feature while the SP35 combines the measured laser distance with its GNSS position and inertial orientation. At measurement distances up to 5 metres, the published three-dimensional laser-surveying error is no more than 2.5 cm. This makes the function useful for site details and general topographic work where direct pole placement is impractical.

AR Real-Scene Stakeout

The SP35 uses an ultra-wide-angle camera to display stakeout guidance over a live view of the working environment. Instead of following only numerical distances and direction arrows, the user can see where the target lies in relation to the actual site.

This can make point navigation easier on open ground, busy building sites and projects with few visible reference features. It is also helpful for construction workers and occasional GNSS users who may find real-scene guidance easier to understand than a conventional plan view. Standard northing, easting and height offsets remain available for completing the final precise placement.

Survey with the Pole Tilted

The tightly coupled IMU compensates for pole tilt of up to 60°, with stated positioning accuracy below 2 cm within the supported tilt range. The survey pole therefore does not need to remain perfectly vertical during every observation.

In practical fieldwork, this helps users collect points beside walls, under vegetation, near parked machinery and on uneven or sloping ground. It can also improve productivity during routine surveys because the operator spends less time centring the pole bubble. The inertial system does not depend on a conventional magnetic compass, reducing disruption from nearby steel structures, vehicles and electrical equipment.

Multi-Constellation GNSS Performance

Each SP35 receiver has 1,408 channels and tracks signals from GPS, GLONASS, BeiDou, Galileo, QZSS, SBAS and NavIC. Multi-frequency and multi-constellation tracking gives the system access to a broad satellite pool, helping it maintain suitable satellite geometry as conditions change across the site.

Under appropriate correction, satellite and environmental conditions, the SP35 provides RTK accuracy of ±(8 mm + 1 ppm) horizontally and ±(15 mm + 1 ppm) vertically. The receivers also support static GNSS observations for control work and post-processing applications. A data update rate of up to 20 Hz provides responsive coordinate information during stakeout and moving surveys.

Final accuracy will still depend on satellite visibility, radio quality, base coordinates, baseline distance, multipath and the operator’s field procedures. Buildings, trees, machinery and reflective surfaces can reduce performance, as they can with any precision GNSS system.

C100T Android Field Controller

The included C100T controller provides a dedicated platform for operating the rover and managing survey data. Its 5.45-inch sunlight-readable touchscreen is designed for outdoor visibility, while the physical keypad provides additional control when wearing gloves or working in wet conditions.

The controller runs Android 11 and uses an eight-core 2.0 GHz processor with 4 GB of RAM and 64 GB of internal storage. This provides a practical hardware platform for compatible survey, mapping and stakeout software. Wi-Fi, Bluetooth, mobile data and dual-SIM support allow the controller to communicate with the receiver, access online services and transfer project information.

A 9000 mAh battery provides up to 18 hours of stated operation. The IP68 housing is intended for work in dusty and wet environments, making the controller suitable for daily use on construction and surveying projects.

Lightweight Receivers for Long Field Days

Each SP35 receiver weighs no more than 780 g. The relatively low weight reduces the load at the top of the survey pole and makes the two-receiver set easier to transport between control points and working areas.

The magnesium-alloy receiver housing is IP68 rated and specified to withstand a two-metre pole drop at room temperature. The operating-temperature range extends from −30°C to +65°C, supporting work through a wide range of seasonal and site conditions.

The internal 6500 mAh receiver battery provides more than 16 hours of typical operation when used as a GSM rover. Battery endurance in base-radio operation will vary with transmission power, temperature, configuration and working conditions.

Applications for Surveying Construction and GIS

Land surveyors can use the set for topographic surveys, cadastral work, site control, detail measurement and stakeout. Construction teams can establish a base on site and use the rover to position foundations, drainage, utilities, kerbs, roads, columns and other design elements.

Civil engineers and site managers can use the system to verify coordinates, check completed work and record progress. GIS teams can collect utility assets, inspection points, poles, signs, chambers and environmental features. Drone operators can establish accurately measured ground control points and checkpoints for photogrammetry and mapping projects.

The local base configuration is especially relevant for remote work, temporary project sites and regions without dependable correction-network coverage. Where an NTRIP service is available, the rover can also be configured to receive corrections through mobile internet.

Configuration and Support from Global GPS Systems

A rover-base system must be configured for the correct radio frequency, protocol, coordinate reference system, base position and survey software. Local regulations governing radio frequencies and transmission power should also be checked before the equipment is used.

Global GPS Systems can help configure the Spherefix SP35 Rover Base Set for local radio corrections, network RTK, construction stakeout, GIS data collection or drone ground-control surveys. Support is available for compatible accessories, field-controller software, coordinate-system setup and practical rover-base workflows.