In the construction industry’s surveying field, the term “RTK” has attracted significant attention in recent years. What differs between traditional optical surveying (using a total station) and the latest satellite positioning technology, RTK surveying, and which is superior? This article provides a detailed comparison of RTK surveying vs total station surveying, focusing on cost-performance. We explain the advantages, disadvantages, and effects of introducing each method, hoping to help site supervisors, survey technicians, and municipal staff involved in surveying work consider efficiency and labor-saving measures.

Table of Contents

• What is total station surveying?

• What is RTK surveying?

• Cost-performance comparison between RTK and total station

• Simple surveying enabled by LRTK

• FAQ

What is total station surveying?

A total station (TS) is an optical surveying instrument that has long been widely used on survey sites. It is an electronic-optical instrument that integrates a theodolite for measuring horizontal and vertical angles and an electronic distance meter for measuring distances, allowing high-accuracy measurement of both angles and distances with a single instrument. Usually a surveying prism (reflector) is set up at the target, and by sighting the prism from the total station, the three-dimensional coordinates between survey points are determined.

Overview of procedures: First, mount the total station on a tripod and carefully level it on a known point (control point). Then determine the precise coordinates and orientation of the setup point using methods such as backsight resection. Once prepared, an operator looks through the total station’s telescope and sights the prism held by another crew member. The instrument automatically measures horizontal angle, vertical angle, and slope distance, and its internal computer calculates the three-dimensional coordinates of the target point (prism position). Repeat this measurement for each required point to collect survey data on site. When measuring many points, it is necessary to move the total station as appropriate and extend the survey network from new control points.

Accuracy: A total station delivers extremely high accuracy at the millimeter level (mm) for short distances. High-end models can achieve errors of only a few millimeters even for targets several hundred meters away. Angle accuracy is also very high, making total stations suitable for precise alignment of structures and displacement measurements.

Advantages:

• High accuracy: As noted above, measurement accuracy at short range is extremely high, making total stations suitable for precision surveys. Especially for vertical measurements, using a level in combination can keep errors to a few millimeters.

• Stable measurements: Another advantage is that measurements are less affected by weather or surrounding materials. They can be used without issue at night or on cloudy days and can accurately measure distances to metal targets. Because they are optical measurements, they are not affected by radio noise.

• Measurable where line-of-sight exists: Measurements can be made anywhere as long as there is a clear line of sight between the instrument and the prism. For example, surveying is possible in tunnels or forests—places where GPS satellite signals do not reach—so long as a direct line of sight is maintained. In urban areas with buildings, measurements are fine as long as the prism is visible.

Disadvantages:

• Time-consuming and labor-intensive: Work generally requires a two-person team (operator + prism holder), increasing labor costs. Robotic total stations that one person can operate do exist but are expensive. When surveying large areas, setting up and re-leveling the tripod and sighting at each survey point take time and reduce efficiency.

• Line-of-sight and direct-distance limitations: Measurements always require a direct line of sight between the instrument and the prism. If buildings or obstacles are between them, measurements cannot be taken, requiring detours or additional relay points. Measurement distance is also limited; accuracy slightly decreases as distance increases.

• Equipment maintenance burden: Total stations are expensive and require regular calibration and maintenance. Each setup requires skill, so training takes time. The equipment is relatively heavy, making transportation and setup burdensome.

What is RTK surveying?

RTK (Real Time Kinematic) surveying is a technique that enhances the real-time accuracy of satellite positioning such as GPS. Typically, two high-precision GNSS receivers are used—a rover (mobile unit) and a base (reference) station—with the base station set up on a known coordinate. The base station computes positioning errors from the satellite signals it receives in real time and sends correction information to the rover via radio or the internet. By applying those corrections, the rover can achieve centimeter-level high-accuracy positioning in real time.

Overview of procedures: First, set up a GNSS antenna and receiver for the base station on a known point near the site (alternatively, you can use public control points or commercial reference station services and omit setting up your own base station). Then the surveyor mounts the rover antenna on a pole and carries the receiver to each point to be measured. The rover receives correction data from the base station at regular intervals and applies the corrections to compute its precise position (this is called obtaining a FIX solution). At each survey point, confirm that the receiver has a FIX solution, then record the point’s coordinates by pressing a button on the device. Repeating this process yields a list of high-accuracy coordinates for multiple points in real time.

Accuracy: RTK-GNSS surveying generally achieves about ±1–2 cm (±0.4–0.8 in) horizontally and ±2–3 cm (±0.8–1.2 in) vertically, depending on distance from the base station and satellite geometry. When the base station is nearby the error is usually within a few centimeters, sufficient for typical civil engineering surveys. However, because satellite signal reception conditions can deteriorate and prevent maintaining a FIX solution, RTK does not match a total station for consistent millimeter-level stability. Still, RTK’s ability to acquire absolute coordinates over wide areas and quickly measure many points at once is a major advantage.

Advantages:

• Labor saving and fast work: RTK surveying can basically be done by a single person. The surveyor walks with the rover and simply presses a button at each point to collect coordinates, allowing fast surveying of large areas. There is no time lost for re-setting instruments or ensuring line of sight, so the number of points obtainable in a day is significantly higher than with a total station.

• Wide-area surveying and immediate results: Using satellite positioning enables simultaneous positioning of distant multiple points based on the same base station. Results are obtained as numerical coordinates on site, so data can be checked immediately and compared with design values.

• Easy coordinate system unification: If the base station is set on a known point in a public coordinate system (such as a global geodetic system), the acquired points’ coordinates are automatically absolute coordinates in that system. This removes the need to later convert to a local coordinate system and makes it easier to integrate and compare survey results with GIS data or design drawings.

Disadvantages:

• Dependence on satellite signals: RTK’s biggest weakness is that its performance depends heavily on satellite signal reception conditions. In urban areas with tall buildings, forests, or other environments where satellite signals are blocked or reflected (multipath), a FIX solution may not be obtainable. Positioning is generally impossible in tunnels or indoors, in which case optical methods like total stations are required.

• Initial cost of introduction: To implement RTK, you typically need at least two high-precision GNSS receivers (base and rover), and the unit price can be comparable to or higher than that of a total station. The overall system cost is not cheap. However, lower-cost GNSS receivers and services that leverage existing control point networks to omit a personal base station have emerged in recent years, lowering the cost barrier.

• Operational difficulty: Specialized knowledge and settings unique to GNSS are required. Understanding satellite geometry, ionospheric effects, formats for base station data, and communication methods (radio modem frequency settings, NTRIP configuration, etc.), plus know-how to obtain FIX solutions, all require experience. Real-time positioning also requires a reliable communication environment, so in mountainous areas without mobile coverage you may need special radios or consider switching to post-processed kinematic (PPK) methods.

Cost-performance comparison between RTK and total station

Traditional optical total stations and new GNSS-based RTK surveying each have different strengths and weaknesses. Here we compare the two in terms of accuracy, working time, personnel (labor cost), environmental adaptability, cost, and ease of operation to consider which offers better cost-performance.

• Accuracy: Total stations deliver millimeter-level accuracy at short distances, excelling at fine dimensional control and displacement measurement. RTK typically achieves about 1–2 cm (0.4–0.8 in) horizontally but can cover wide areas and directly obtain absolute coordinates even without local control points. Vertical accuracy does not match that of a total station combined with leveling, but RTK’s accuracy is practically sufficient for general surveying tasks.

• Working time: Total stations require time for setup and backsight measurements, and moving the prism between points takes time. When surveying wide areas, frequent re-setup is necessary, limiting the number of points observable per day. RTK requires initial setup of a base station, but once a FIX solution is obtained, points can be measured on the move, dramatically reducing total surveying time. For cases with hundreds of points, RTK is overwhelmingly faster.

• Personnel (labor-saving effect): Total station surveys typically require teams of 2–3 people (operator, recorder, prism holder). RTK surveys can be completed by a single person, enabling significant labor savings. Robotic total stations with automatic tracking can also enable single-person operation, but that requires additional costly equipment. Overall, for wide-area surveys or many-point observations, RTK’s labor reduction is pronounced.

• Environmental adaptability: In urban areas or indoors where the sky is obstructed, total stations have an advantage. Optical surveys can work where line of sight is maintained, while RTK-GNSS cannot function without satellite signals. Conversely, RTK shines on large sites, mountainous areas, and disaster sites where there may be no ground control points—if the sky is open, RTK can quickly survey distant points without line-of-sight constraints.

• Cost: Looking at unit prices, both total stations and RTK GNSS receivers are expensive surveying instruments. High-end models of either can require initial investments in the millions of yen. Operating costs for total stations include periodic calibration and consumables (batteries). RTK also incurs communication costs (data SIMs or terminals) and, if using commercial correction services, service fees. While initial costs depend on circumstances, RTK’s potential to reduce labor and shorten work time can make it more economical in the medium to long term. Affordable RTK equipment and convenient positioning services have become more common recently, lowering initial cost barriers.

• Ease of operation: It’s hard to say definitively which is easier. Total stations require skill for each setup and measurement but are generally intuitive and encounter fewer unexpected issues. RTK-GNSS needs more know-how for initial settings and radio conditions, but once operators are familiar, setup is simpler and the acquired data are ready as digital coordinates, minimizing post-processing. Both require experience, but RTK tends to offer easier data integration and is better suited for ICT construction and BIM/CIM workflows. Considering the ongoing digitalization of construction sites, RTK’s operational advantages are significant.

Simple surveying enabled by LRTK

Among the latest RTK technologies, LRTK has attracted particular attention in recent years. LRTK is an evolution of conventional RTK that balances high positioning accuracy and mobility. Its main feature is that, by receiving dedicated correction information via satellite communication or proprietary networks, it can achieve centimeter-level positioning in real time without installing a site base station. As a result, equipment preparation is greatly simplified and the time required to start positioning is dramatically reduced. The high mobility that allows you to turn on the receiver on site and begin surveying immediately represents a leap from “RTK that carries a base station” to “RTK not tied to a base station.”

LRTK-compatible devices provide accuracy comparable to or better than conventional RTK (errors within a few centimeters) using the latest GNSS technology. Because correction data can be obtained over a wide area, there is no need to move the base station or switch to another reference station during a large-area survey. Even in mountainous regions where radio communication previously made RTK operation difficult, bringing an LRTK-compatible receiver enables surveying. In short, the labor of installing and maintaining a base station is eliminated, so surveyors can bring a single set of necessary equipment to the site, start measuring immediately, and obtain results on the spot.

Sites that have introduced LRTK report dramatic improvements in efficiency and productivity. For example, on a road construction project, an LRTK-compatible GNSS receiver measured pavement subsidence over an area in a short time, reducing a survey that previously took days to just a few hours. For railway infrastructure inspections, workers carrying LRTK devices measured track deformation in real time while moving and could immediately determine whether repairs were needed. In the construction industry, companies are increasingly adopting LRTK as part of ICT construction supporting the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction initiative, and LRTK is expected as a new surveying method that combines dramatic labor saving and immediacy that were difficult to achieve with total stations alone.

Thus, LRTK incorporates the strengths of both RTK and total station surveying and is revolutionizing on-site surveying. Centimeter-level rapid surveying leads directly to shortened construction periods and cost reduction. Since one person can cover a wide area, it is also effective against the growing labor shortage. The equipment is compact and portable and designed to be easy to use even for sites adopting RTK for the first time. LRTK will be a powerful tool for future infrastructure inspection and disaster response. If you want to dramatically improve surveying cost-performance, it is worth considering the next-generation solution of LRTK.

FAQ

Q: Which is more accurate, RTK surveying or total station surveying? A: Total stations provide higher relative accuracy at short ranges and can measure at the millimeter order. RTK achieves about 1–2 cm (0.4–0.8 in) horizontally but has the advantage of directly obtaining absolute coordinates. For general civil engineering surveys, RTK accuracy is sufficient in most cases, but where millimeter-level precision is required, a total station is preferable.

Q: Can RTK surveying be used at any site? A: RTK is powerful in open outdoor sites, but it does not function where satellite signals cannot reach—such as in urban canyons with tall buildings, forests, tunnels, or indoors. In such places, optical methods like total stations are necessary. Conversely, RTK is effective in rugged mountainous terrain or for wide-area surveys where line-of-sight is difficult.

Q: What is needed to start RTK surveying? A: Basically, two high-precision GNSS receivers (for base and rover) connected via communication are required. However, if you use an existing network of reference stations or regional correction services, RTK positioning is possible without setting up your own base station. For example, network RTK via internet corrections or LRTK systems that do not require a base station can achieve centimeter-level surveying with a single GNSS receiver.

Q: How much does it cost to introduce RTK? A: Costs vary by model and system. Purchasing dedicated high-performance RTK-GNSS equipment new can require investments in the millions of yen. On the other hand, low-cost receivers and subscription-based correction services have appeared. Considering not only initial costs but also labor savings and reduced work time, RTK often has better overall cost-performance.

Q: What is LRTK and how does it differ from conventional RTK? A: LRTK is a surveying solution that applies the latest RTK technology and enables real-time high-accuracy positioning without installing a base station. By obtaining dedicated correction data, it removes the need for a personal reference station and reduces the amount of equipment to bring to the site. Accuracy is comparable to conventional RTK, while ease of use and mobility are greatly improved. With LRTK, a single operator can efficiently survey wide areas and achieve results with less cost and time than before.