RTK GPS Beginner’s Guide: Fundamental Knowledge from How It Works to How to Use It

Table of Contents

• Introduction

• What is RTK GPS?

• RTK GPS Mechanism and Methods - Standalone RTK (own base station method) - Network RTK (VRS method) - Utilizing Satellite Augmentation Service (CLAS)

• How to Use RTK GPS — Procedures

• Use Cases for RTK GPS (from public surveying to agriculture)

• Benefits of Introducing RTK GPS

• Simple RTK Surveying Using Smartphone-Attached LRTK

• Frequently Asked Questions (FAQ)

Introduction

On surveying sites, ordinary GPS (GNSS) position measurements typically incur errors of several meters, which is insufficient for fine positioning or precise height measurements. For example, in topographic surveys or confirming land boundaries, meter-level offsets can be critical, and in construction quality control (inspection of the shape and dimensions after construction) centimeter-level accuracy is required to verify whether work matches the drawings. Traditional methods to achieve high accuracy require skilled surveyors and significant effort, consuming large amounts of personnel time. Operating surveying equipment (total stations or large GNSS receivers) normally requires two people, and surveying wide areas requires enormous working time.

RTK GPS surveying is a trump card to solve these problems. RTK (Real Time Kinematic) is a method that dramatically improves positioning accuracy by using correction information from a base station to correct GPS measurement errors in real time. Ordinary GPS can have errors of up to about 2 m (6.6 ft), but using RTK can reduce errors to within a few centimeters. By combining a base station and a rover receiver for relative positioning, errors that would be 5-10 m (16.4-32.8 ft) with single-point positioning can be corrected down to a few centimeters. As a result, RTK surveying generally achieves around 2-3 cm (0.8-1.2 in) horizontal accuracy and about 5 cm (2.0 in) in height, enabling high-precision positioning and height management on site that was previously difficult.

RTK is also revolutionary in terms of efficiency. Because it provides high-precision positioning in real time, the need for post-processing is reduced and work can proceed while confirming results on site. Advances in equipment also mean that one person can increasingly perform surveying tasks alone. While two-person teams were once the norm, compact RTK-GNSS receivers paired with smartphones now allow many situations where a single person can survey with a smartphone in hand. In an era of labor shortages and demand for reduced work time, RTK GPS is attracting attention as a solution that simultaneously solves precision deficiencies and improves efficiency.

What is RTK GPS?

RTK GPS is a high-precision GNSS positioning method that enables centimeter-level positioning by correcting GPS measurement errors in real time. Ordinary GPS positioning incurs meter-level offsets due to atmospheric effects and satellite orbit errors, but RTK uses "correction information" to cancel these errors. Specifically, a base station installed at a known, accurate coordinate location and a moving rover that receives satellite signals simultaneously both receive satellite signals; the error information obtained at the base station is sent to the rover. The rover applies that correction to its raw positioning values, reducing errors that would be several meters on a single receiver to a few centimeters. Through this mechanism, RTK positioning allows acquisition of high-precision position information in real time.

In other words, RTK GPS is a method of improving your own positioning by sharing the "satellite positioning errors as seen from a base station." Corrections are exchanged via radio or the Internet, and the closer the base station is to the rover, the more effective the error cancellation. Traditionally, users had to provide their own base station, but nowadays national and private base station networks are available and can be used to obtain correction data. In Japan, there is also CLAS, a system that uses QZSS (Quasi-Zenith Satellite System) to receive correction information directly from satellites without a base station. Thus, while RTK GPS broadly refers to the same concept, there are several methods depending on how correction information is obtained. Next, let’s look at representative RTK positioning methods.

RTK GPS Mechanism and Methods

To achieve centimeter-level accuracy with RTK positioning, it is necessary to continuously receive correction data from a base station. Depending on how correction data is obtained, RTK operation is mainly classified into the following methods.

Standalone RTK (own base station method)

This method involves installing your own GNSS receiver as a base station near the survey site and continuously transmitting correction information from it to the rover by radio. It is a standalone RTK where you set up your own base station; the configuration is a simple one-to-one system, but preparing and installing the base station equipment requires effort. Radio communication range is limited (on the order of several km to 10 km), and accuracy gradually declines as you move away from the base station. For example, errors that cannot be fully corrected tend to increase if you are more than 10 km away. Still, this method is used where mobile communication is unavailable or when a company wants to manage accuracy in-house. Although setting up a base station requires effort, it can be operated without relying on communication infrastructure, so it is usable in mountain areas or other sites without network connectivity (provided radio coverage is available).

Network RTK (VRS method)

This method receives correction information via the Internet using an electronic reference point network established nationwide by the Geospatial Information Authority of Japan or private providers. Users equip the rover with cellular data (mobile network) and connect to a distribution service with client settings using the Ntrip standard protocol. The service generates and transmits data from a virtual reference station (VRS) near the user, so no personal base station is needed and distance-related accuracy degradation is largely eliminated. Because a wide-area reference network is shared, this method is very rational, but generally service fees are charged monthly or annually. It also cannot be used in areas without mobile coverage. Nonetheless, because it removes the hassle of setting up a base station, network RTK services (e.g., regional survey bureaus or private VRS providers) are widely used in urban and large-area surveys.

Utilizing Satellite Augmentation Service (CLAS)

Japan has a unique system called CLAS (Centimeter Level Augmentation Service) provided by the Quasi-Zenith Satellite System (QZSS). This system transmits correction information directly from satellites, so no base station or communication line is required to achieve centimeter-level positioning. As long as the user has a compatible GNSS receiver, CLAS can be used free of charge across almost all of Japan (where satellite sky visibility exists, including mountainous areas, remote islands, and offshore locations). Technically, CLAS adopts a PPP-RTK method: error information observed by the Geospatial Information Authority’s GEONET is aggregated and transmitted via QZSS on an L6 band signal. The user’s receiver receives and analyzes that signal and performs real-time correction, so a standalone receiver can achieve centimeter-level accuracy without setting up a base station or fetching data over the network.

Traditional RTK required either installing a base station or using communication infrastructure, but CLAS removes those hurdles. In environments where base station equipment or networks are unusable—such as deep mountains or right after a major disaster—CLAS-compatible receivers can continue real-time positioning, which is a major advantage. For example, after recent large earthquakes in rural areas where local base stations and networks were cut, small CLAS-compatible RTK receivers proved useful for recording the disaster site; high-precision data obtained via satellite enabled rapid 3D modeling of damage and sharing among stakeholders. CLAS thus represents a new form of RTK positioning and is extremely useful for sites with unstable networks or for wide-area surveying.

How to Use RTK GPS — Procedures

Let’s review the general procedure and key points for using RTK GPS in the field. Below we explain the workflow step by step from preparation to positioning (measurement) and finally data storage and sharing.

• Preparation of equipment and environment: Before going to the site, assemble and inspect all RTK equipment. Prepare an RTK GNSS receiver (rover terminal) and a controller device (field tablet or smartphone), and make sure the dedicated app or software is installed. Fully charge batteries for long work periods and bring spare power if available. A monopod or pole and a bubble level for centering are useful for placing the device precisely above the survey point. Scout the site environment in advance and confirm that the sky is sufficiently open. Buildings and trees can block satellite visibility or cause signal reflections (multipath), which reduce accuracy, so choose as clear a location as possible. Note that RTK positioning cannot be performed in environments where satellite signals cannot be received, such as under elevated structures or inside tunnels. Communication environment is also important: if you plan to use network RTK, check beforehand whether mobile communication is available at the site (if no coverage, consider using your own base station or CLAS as discussed later).

• Connecting to base station (receiving correction data): Upon arrival, power on the RTK receiver and controller, and set up the equipment. Start the dedicated app on the smartphone or tablet, pair it with the GNSS receiver via Bluetooth, and configure correction data reception. There are three main ways to obtain correction information: (a) For network RTK, enter the Ntrip server address and login information specified by the service provider into the app to connect the rover to the correction data stream. Selecting the appropriate regional base station or virtual reference point provides accurate corrections. (b) If using your own base station, set up another GNSS receiver on a known point in base station mode and distribute corrections to the rover via WLAN or low-power radio (920 MHz band, etc.). When operating a local base station, you must preconfigure the base station’s accurate coordinate values. (c) If using CLAS, a receiver that supports CLAS can receive augmentation signals directly from satellites without special communication. For compatible equipment, simply enable CLAS mode in the app and satellite corrections are automatically applied (available across almost all of Japan). With any method, once correction data is correctly received, the GNSS positioning mode will switch from normal “single” or “float solution” to a “fixed solution (Fix).” A Fix solution means integer ambiguities based on carrier-phase differences have been resolved, providing centimeter-level accuracy. Achieving a Fix solution is the primary goal in RTK surveying.

• Positioning (measuring and recording points): Once corrections are applied and positioning stabilizes with a Fix solution, begin observing points. For single-point positioning, move the rover to the point to be measured and press the “position” button on the device or app; the high-precision coordinates at that moment are recorded. Latitude, longitude, and height (ellipsoidal height or orthometric height) are saved along with time, point name, and RTK quality info such as Fix/Float status. Many systems allow you to add identifiers or notes—e.g., “XX control point” or “center of YY intersection”—which is useful for later clarity. Some devices and apps offer a continuous logging mode, which automatically records positions at set intervals while you walk through an area. For example, setting 10 points per second allows you to collect many point-cloud data while moving, which is useful for mapping ground elevations over an area or scanning the 3D shape around structures. Recent smartphone apps integrate LiDAR scanning with RTK to perform high-precision 3D surveys, enabling real-time point-cloud measurements combined with RTK coordinates. During surveying, always monitor the current positioning status (Fix or Float, number of satellites, estimated precision); if a temporary Float occurs, exclude those data or remeasure the same point.

• Saving and checking measurement data: After observations are complete, properly save the acquired data and verify accuracy. RTK devices or apps display a list of measured points and quality information for each point (Fix/Float status, estimated error, number of satellites used), so check for any uncertain points. Points recorded with a Fix solution are generally high precision, but take care if a point was recorded as Float. If necessary, remeasure that point or use an average of multiple measurements for the same point to increase reliability. If a nearby known control point (e.g., bench mark or electronic reference station) is available, measure it as well and compare the obtained coordinates to the known values. If errors are within a few centimeters, the system is functioning normally; large discrepancies may indicate coordinate system misconfiguration or wrong correction data selection and require reconfiguration. Performing such double checks and catching errors early is key to producing accurate deliverables.

• Sharing and utilizing data: Saved positioning data should be shared and utilized as needed both within and outside the organization. Many systems allow one-click upload of measured data to cloud services from the field device, enabling office PCs to view field measurement results immediately. Storing data in the cloud protects it in case a field device is lost or damaged, and eliminates the need to manually transfer data via USB or cable. With sharing settings enabled, colleagues or clients elsewhere can review measurement results nearly in real time, facilitating smooth communication. It is also important to import acquired data into CAD or GIS for practical use: export measured point coordinates from the app as CSV or DXF and overlay them on design drawings to check as-built conditions, or plot measurement points on GIS maps for management. Compared to the era of handwritten field notebooks, digital data can be used directly for drawing and calculation, dramatically improving work efficiency. Thus, high-precision data obtained by RTK surveying can be verified and shared on site and seamlessly connected to office design and reporting workflows.

Use Cases for RTK GPS (from public surveying to agriculture)

RTK GPS, leveraging its high precision and mobility, is used across a wide range of fields from surveying and construction to disaster response and agriculture. Here are representative practical use cases.

• Public surveying and infrastructure development: RTK is used for control point surveys and land surveys on public works conducted by national and local governments. Using network RTK services based on an electronic reference network allows you to obtain survey results directly linked to the public coordinate system anywhere in Japan. Traditionally, a lot of effort was required for traverse and leveling from known points, but RTK enables rapid acquisition of control coordinates and elevations, improving productivity. For example, in topographic surveys for roads or bridges, using RTK-GNSS allows rapid elevation data acquisition even in difficult sites, which is valuable for post-disaster recovery planning.

• As-built management and quality inspection: RTK positioning is used at construction sites to verify whether completed structures or earthworks meet required specifications. For instance, when checking curb or pavement positions in road construction, comparing design coordinates with RTK-measured coordinates immediately reveals discrepancies. RTK-acquired coordinates meet accuracy requirements typically demanded by the Ministry of Land, Infrastructure, Transport and Tourism’s electronic delivery standards and as-built management guidelines (generally around ±5 cm (±2.0 in)), allowing quality to be demonstrated directly with coordinate data rather than relying on photogrammetry. Measurement results can be organized in Excel to create as-built management tables, or shared on the cloud with supervising staff to immediately discuss corrective actions, making RTK a powerful tool for digital construction.

• Disaster response and emergency surveying: Right after a major disaster, roads and communications may be cut, making conventional surveying difficult. Even in such environments, RTK-capable GNSS receivers allow rapid on-site recording. In disaster zones where mobile communications are down, RTK devices that can receive satellite-based corrections such as QZSS CLAS are especially effective in initial surveys. For example, a lone investigator can walk a quake or landslide site with an RTK receiver, measuring the positions of collapsed structures and ground fissures. Acquired data can be used to instantly generate 3D damage maps and shared among stakeholders, greatly speeding up initial response and restoration planning.

• Agriculture and forestry (smart agriculture): RTK use is advancing in surveying and work support for large farmland and forest areas. Centimeter-level positioning helps accurately measure boundary lines between fields and assess elevation differences for drainage planning; meter-level errors are inadequate for boundary confirmation, but RTK or CLAS-capable GNSS enables precise boundary surveys that are difficult with tape measures or small stakes. RTK is also indispensable for automatic steering systems in autonomous tractors. GPS alone yields meter-level errors that make straight driving difficult, but combining RTK-GNSS reduces errors to centimeter levels, eliminating variability in planting or harvesting runs. Improved accuracy reduces duplicate work and missed areas, saving fuel and time. In forestry, RTK supports boundary confirmation and road network planning in mountainous terrain. Even where base stations are not nearby, CLAS-capable devices allow a technician to enter a forest and perform precise positioning, dramatically improving survey efficiency in steep, variable terrain.

• Land boundary confirmation and property surveys: RTK is also useful for private land and property surveys related to boundary confirmation and land acquisition. Previously, setting out involved referencing existing boundary markers and using a total station, but if you input known boundary point coordinates from the legal records into an RTK receiver, you can navigate to those positions in the field. RTK apps can display the distance and direction from the current position to the target point in real time, enabling you to locate the exact stake position within centimeters. Old boundary stakes hidden by vegetation can be easily found by following RTK guidance. RTK-based positioning guidance is effective during on-site inspections and directly speeds up and reduces labor for property surveys.

As described above, RTK GPS is active in various fields from public infrastructure to private use. High-precision positioning may have seemed specialized in the past, but now not only surveyors but also site supervisors, technicians, and independent farmers are starting to use RTK as a practical tool.

Benefits of Introducing RTK GPS

Finally, from a practitioner’s perspective, here are the benefits of introducing RTK GPS. Beyond accuracy improvements, RTK can transform how field work is conducted.

• Dramatic improvement in positioning accuracy: The main benefit is improved accuracy. While single-receiver GPS can deviate by several meters, RTK can determine positions with errors of a few centimeters. Vertical accuracy of around 5 cm (2.0 in) is achievable, so tasks that required leveling may be simplified. Higher accuracy makes as-built management and quality verification straightforward, providing numerical evidence of conformance to design drawings. Improved accuracy also reduces surveying errors, preventing rework and additional surveys.

• Improved work efficiency and speed: Because high-precision results are available in real time, work can proceed while checking data on site. Tasks that once required returning to the office for calculation and adjustment can now be completed on site, saving significant time. RTK-GNSS can measure many points over a wide area in a short time, which is valuable for speed-focused tasks like measuring numerous topographic points to calculate earthwork volumes. Increased throughput per hour helps meet tight project schedules. Reduced mistakes and rework also smooth overall project progress.

• Labor savings and reduced personnel: Introducing RTK allows reduction of survey staffing. Tasks once done by two-person teams can often be performed by a single person using an RTK rover to walk measurement points. Especially with recent smartphone-connected RTK devices, one person can mount the receiver on a pole and handle setup, observation, and staking without assistants. In the labor-short construction and surveying industries, the ability for one person to conduct accurate surveys is a major advantage. Combined with time savings, this helps reduce overtime and long work hours, supporting work-style reform.

• Instant sharing and digital integration: RTK survey data are digital and can be used immediately on site. Systems integrated with cloud services allow field-obtained data to be shared instantly with the office so remote managers can check in real time, reducing communication loss and speeding decision-making. Data can be exported as CSV or DXF and imported into CAD or GIS, enabling seamless integration with subsequent tasks (design, analysis, reporting). Eliminating paper records and manual re-entry reduces human error and enhances overall workflow efficiency. Digital archives such as geo-tagged photos are easily created and become valuable records for maintenance and future comparisons.

• Democratization of technology (making surveying accessible to anyone): High-precision survey instruments used to be expensive and required specialized knowledge, limiting them to trained surveyors. But with advances in RTK-GPS systems, surveying tools are becoming usable by non-specialists. If site supervisors, construction managers, or in-house workers each carry a device and can measure or stake points when needed, the efficiency and accuracy of work will improve dramatically. Being able to survey without waiting for a survey team increases on-site autonomy and overall organizational productivity. Modern smartphone-connected devices are designed with intuitive operation so even beginners can use them, advancing this democratization of technology.

From these benefits, RTK GPS is more than a tool for improving survey accuracy; it can be a key technology to promote field DX (digital transformation). Real-time access to high-precision location information helps reveal previously hidden issues and enables efficient construction management that eliminates waste, producing various ripple effects.

Simple RTK Surveying Using Smartphone-Attached LRTK

Understanding RTK GPS’s usefulness may raise concerns that implementing it is complicated or burdensome. Indeed, until recently RTK surveying required expensive dedicated equipment and advanced expertise. However, technological innovation has produced RTK-GNSS receivers that anyone can use easily. A representative example is the smartphone-attached high-precision GNSS terminal series called “LRTK.”

LRTK is a pocket-sized RTK-GNSS receiver system developed by a startup from the Tokyo Institute of Technology, designed for integration with smartphones. The ultra-compact device integrates antenna, receiver, battery, and communication module in one unit and weighs a few hundred grams. It attaches to a dedicated smartphone case with one touch and only slightly increases the phone’s thickness; despite its compactness, its performance rivals traditional survey-grade equipment. Attach it to a smartphone and launch the dedicated “LRTK” app, and smartphone GPS that previously deviated by several meters instantly becomes centimeter-level accurate. Correction reception from base stations is automated in the app, and models supporting network RTK or CLAS can start high-precision positioning as soon as they are powered on in the field.

With smartphone-attached RTK devices like this, RTK surveying stops being something special. Anyone can carry a pocketable surveying tool, take it out when needed, and measure points—realizing the concept of “one versatile surveying device per person.” If site supervisors or construction managers carry LRTK-like devices, simple measurements that once required a survey team can be done in-house. This not only increases on-site responsiveness and eliminates small surveying wait times, but also enables immediate cloud sharing of results for rapid decision-making among stakeholders. The price is also far more accessible than traditional equipment (specific pricing is omitted here), so small companies and sole proprietors can more readily adopt it.

As this guide has described, RTK GPS is a powerful solution that can resolve surveying challenges, and the arrival of new tools like LRTK has greatly lowered the barrier to access. If your site suffers from problems like frequent rework due to insufficient accuracy, construction halted by waiting for surveys, or lack of personnel to devote to surveying, consider introducing RTK GPS. With a compact device that attaches to a smartphone and an easy-to-use app, you can start centimeter-level surveying tomorrow. RTK GPS, offering accuracy improvement, efficiency, and labor savings, can become a reliable ally to greatly boost productivity at surveying and construction sites.

Frequently Asked Questions (FAQ)

Q: What is the difference between RTK-GPS and ordinary GPS positioning? A: The main difference is the magnitude of positioning error. Ordinary GPS (GNSS) single-receiver positioning typically produces meter-level errors due to satellite signal errors, while RTK-GPS uses correction information from a base station to cancel those errors and keeps errors within a few centimeters. In short, RTK achieves high accuracy by relative positioning with reference to base stations rather than relying solely on a single receiver. RTK also provides high-precision results in real time, so you can obtain results on site without waiting for post-processing.

Q: What equipment and preparation are needed to perform RTK surveying? A: The basics are an RTK-capable GNSS receiver (rover) and a source of base station correction data. Rover devices can be dedicated standalone receivers or smartphone/tablet-combined types (e.g., smartphone-attached LRTK terminals). To obtain base station corrections, consider the following preparations: (1) If subscribing to a public or private RTK base station service: ensure mobile connectivity at the site so you can receive corrections over the Internet (configure login information in the compatible app). (2) If setting up your own base station: prepare another GNSS receiver and place it on a known coordinate point, and provide radio distribution of corrections to the rover (e.g., using low-power radio). (3) If using CLAS: compatible receivers can obtain corrections from satellites without additional communication, so no special preparation is required. In any case, it’s useful to bring stable poles, tripods, bubble levels, and mobile batteries as field accessories.

Q: What level of accuracy can be achieved with RTK-GPS? A: Under good conditions, typical accuracy is about 2–3 cm (0.8–1.2 in) horizontally and about 5 cm (2.0 in) vertically. This is achievable with a Fix solution when satellites are well tracked and base station corrections are properly applied. Time to obtain a Fix is relatively short—usually from a few seconds to a few tens of seconds. However, surrounding environments can block satellite signals or cause multipath effects that increase errors. Accuracy may also degrade slightly (on the order of a few centimeters) when far from the base station. For CLAS use in Japan, published nominal values include approximately 6 cm (2.4 in) horizontal and 12 cm (4.7 in) vertical within 95% confidence. In any case, RTK is significantly more accurate than meter-level ordinary GPS.

Q: Can RTK surveying be performed where the Internet is not available? A: Yes. In such cases, use methods that do not depend on the network. First, install your own base station near the site and transmit corrections by radio; this conventional method enables RTK positioning without cellular coverage. Another option in Japan is CLAS: CLAS-compatible receivers can obtain satellite corrections directly and achieve centimeter-level positioning without an Internet connection. For example, in mountainous areas or disaster sites where networks are down, if CLAS signals are receivable, high-precision positioning can be continued on site. By switching methods according to area and situation, RTK surveying can be performed without relying on the Internet.

Q: I want to introduce RTK for the first time. Is operation and management difficult? A: Compared to the past, it has become much easier and more intuitive. Current RTK-GNSS equipment is user-friendly, and beginner users can start positioning by following app-guided setup. Especially for smartphone- or tablet-connected products, app screens are clear, and functions such as point recording and coordinate system conversion are often automated. You do need to understand basic satellite positioning and coordinate systems at first, but once you learn the workflow, operations are mostly straightforward. Manufacturers commonly offer training and support, so help is available if needed. Even those unfamiliar with field surveying can master the devices after a few days of practice. In fact, people outside surveying specialties—such as civil engineers and site workers—are increasingly using RTK equipment and often report it’s easier than expected.

Q: I heard you can do RTK surveying with a smartphone. Is that true? A: Yes. Using recent smartphone-attached RTK-GNSS receivers, your everyday smartphone can become a centimeter-accuracy surveying device. For example, attaching a device like the “LRTK Phone” to your phone and running the dedicated app enables high-precision positioning that the phone’s built-in GPS alone cannot achieve. These compact devices integrate antenna and battery, and are easy to carry. Some products let you record positions, compare with drawings, and display AR guidance on the smartphone screen, making the smartphone a truly versatile surveying tool. Smartphone-based RTK is accessible even without specialized survey equipment, so use is spreading among site supervisors, construction engineers, and agricultural workers. It may sound surprising, but trying it will likely impress you with the accuracy and convenience.