Table of Contents

• What is RTK (Overview of Real Time Kinematic Positioning)

• Characteristics of Own Base Station RTK

• Characteristics of Network RTK

• Own Base Station vs Network RTK: Which Is Easier?

• Simple Surveying with LRTK

• FAQ

RTK is a technology that performs high-precision satellite positioning in real time. Standalone GPS positioning typically produces errors on the order of several meters, but by using RTK (Real Time Kinematic), positions can be determined with errors within a few centimeters (within a few inches). RTK positioning is increasingly used in civil engineering and construction sites, becoming an indispensable technology for achieving efficient and accurate surveying. This article compares the two main methods of introducing RTK—“own base station” and “network RTK”—and explains the advantages and disadvantages of each. We also consider which one is easier to implement, and at the end introduce a new simple surveying method called LRTK.

What is RTK (Overview of Real Time Kinematic Positioning)

RTK is a positioning method that uses correction information transmitted from a reference station (base station) to correct the position of a mobile station (rover) in real time. Standalone GNSS positioning with a single receiver can produce position deviations of about 5–10 m (16.4–32.8 ft) due to satellite signal errors, but RTK positioning uses two GNSS receivers to cancel out error factors and can improve accuracy to the level of a few centimeters (a few inches) in both horizontal and vertical directions. Specifically, a base station installed at a known coordinate observes satellite data and the data from the rover whose position is to be measured are compared; the difference (error) between the two is sent to the rover as correction information. The rover applies this correction information in real time to compute high-precision coordinates that cannot be obtained by standalone positioning.

The advantages of RTK surveying are that it achieves both “immediacy” and “high accuracy.” Traditionally, obtaining centimeter-level accuracy required static GNSS surveying or optical surveying with long observation times, but with RTK you can take equipment to the point to be measured and get results on the spot in a short time. For this reason, RTK is used in a wide range of applications such as as-built surveys and batter board (layout) work on civil engineering projects, guidance for autonomous tractors in agriculture, and improving the accuracy of drone surveys.

To use RTK, it is necessary to transmit correction data from the base station to the rover by communication. There are broadly two communication methods: “install your own base station and transmit corrections by radio” and “receive correction information via the Internet using an existing reference station network (network RTK).” Below we look at the characteristics of these two approaches: own base station RTK and network RTK.

Characteristics of Own Base Station RTK

The own base station method involves installing and operating a GNSS receiver as a base station at the site oneself. An antenna is set up on a known point near the site (a point whose accurate coordinates are already known) to serve as the base station, and the base station sends correction information by radio to correct the rover’s positioning. For example, when performing own RTK at a construction site, one GNSS receiver may be fixed to a local control point or a Class 4 triangulation point, and the surveyor carries a second receiver to perform the survey. If the base station and the rover can communicate directly, cm-level positioning is possible in real time even without an Internet connection, provided radio signals can be received.

Advantages:

• Autonomous communication: Because the base station and rover are connected directly by radio, operation does not depend on cellular signals or external services. RTK positioning can continue wherever radio reaches, even in mountainous areas or places without communication infrastructure. Using local radios (UHF band or specified low-power radios, etc.) can deliver correction data stably within a small site.

• Low running costs: Although initial investment in base station equipment is required, once you own a base station you do not need to pay for external correction services (monthly subscription fees, etc.). For long-term, frequent RTK surveying, self-operation can be more cost-effective than continually paying service fees. If multiple rovers are used simultaneously, one base station can distribute correction information to all of them, allowing multiple people to survey without additional usage fees.

• Manageable stable accuracy: If you install your own base station at a known point, you can always achieve consistent accuracy within that site. Keeping the baseline length between the base station and rover short reduces atmospheric error effects and yields consistently high accuracy. By strictly managing the base station coordinates internally, you can guarantee the absolute accuracy of measurements in your own reference frame.

Disadvantages:

• Initial installation hurdles: You need a full set of equipment for the base station, including a GNSS receiver and antenna, radio equipment, tripods/fixings, and batteries. High-performance GNSS receivers are expensive, so initial investment can be large. Also, depending on the radio frequency used, you may need to apply for a radio station license. Selecting equipment and handling license procedures require specialized knowledge and preparation, which can be a hurdle.

• Operational effort: Each time you start surveying you must set up and configure the base station. The base station should be placed in a stable location with a clear view of the sky; if it is on a known point, you input its coordinates, and if it is on an unknown point you need to observe it for later offset correction. Setting up and leveling equipment can take time, so you cannot always start surveying instantly. For short jobs or quick inspections, the setup effort can reduce efficiency.

• Limited applicable range: Because accuracy degrades when the base station and rover are too far apart, the own base station method is basically suitable for surveys near the base station. Generally, high accuracy is maintained within a few kilometers, but if the site is tens of kilometers from the base station, errors accumulate and it becomes difficult to obtain an RTK fixed solution. To cover large areas you must move the base station sequentially or prepare relay stations, complicating operations. When surveying distant separate sites, you need to re-establish the base station each time, reducing mobility.

Characteristics of Network RTK

Network RTK receives correction information via the Internet from a pre-established regional reference station network. Also called network RTK, this method lets users utilize correction data from fixed stations deployed nationwide, such as the Geospatial Information Authority of Japan’s Continuously Operating Reference Stations, without installing their own base station. In practice, the rover’s receiver connects to the Internet via a cellular connection or mobile router, and accesses a correction data distribution service via a protocol called Ntrip. The service provider’s server generates a virtual reference station (VRS) near the user’s position and returns real-time correction information for that virtual point. This enables positioning with accuracy as if a nearby base station were present.

Advantages:

• Easy initial setup: There is no need to prepare additional base station equipment as with the own base station method; you can start with just an RTK-capable GNSS rover and a communication device (smartphone or tablet). There is no need to set up a base station in the field, so preparation time before starting surveying is short. Even without specialized knowledge, users can follow settings provided by the service (connection ID, coordinate system settings, etc.) to start operation relatively easily, making it friendly to beginners.

• Usable over wide areas: Because network RTK uses a network of reference stations covering a region, it can maintain accuracy even at locations far from any single base station. Errors that increase with long distances are reduced by interpolating data from multiple reference stations on the network side to create correction information. Except in extremely remote mountain locations, cm-level positioning is achievable anywhere nationwide where cellular signals are available. Because you can always receive appropriate correction data while moving, network RTK is well suited for surveying tasks with large movement ranges or for crews that move between multiple sites.

• Positioning results tied directly to public coordinate systems: Network RTK correction information is typically generated based on official coordinate references (in Japan, JGD2011/JGD2022, etc.). Therefore, the resulting coordinates correspond directly to the official geodetic system. Unlike the own base station method, you generally do not need to tie results later to known points for coordinate correction. Being able to always obtain positions in the public coordinate system makes it easy to compare data across sites and to check coordinates against design plans.

Disadvantages:

• Dependence on communication environment: Internet connectivity is essential, so in locations with poor signal you cannot receive correction data and RTK positioning will not work. This is a major constraint for work in mountainous areas, underground, or areas outside cellular coverage. Additionally, if there are communication outages or server maintenance on the service side, users cannot resolve the issue and work will be interrupted. Compared with own base stations, there is a risk from factors you cannot control.

• Ongoing usage costs: Using a network RTK service usually requires a contract with a correction data provider and payment for the correction data. Pricing varies by service—monthly or yearly flat rates or usage-based billing are common. Long-term frequent use can lead to substantial total costs. Also, if multiple GNSS devices are used simultaneously, each may require its own contract or license, increasing costs as the number of units grows.

• Service area limitations: Coverage of reference station networks varies by country and region, so some services may not cover all areas. In Japan, VRS services utilizing the Geospatial Information Authority’s CORS are nationwide, but abroad or on remote islands the available network RTK services may be limited. Also, different providers may use different geodetic or height reference systems, so coordinate transformation or vertical datum corrections may be necessary depending on the application.

Own Base Station vs Network RTK: Which Is Easier?

We have reviewed the characteristics of own base station RTK and network RTK; which is actually easier to use in practice? In short, for those introducing RTK for the first time or who are not familiar with the equipment, network RTK is the easier option. Network RTK requires minimal equipment and the field setup is simple. The own base station method demands more equipment preparation and prior knowledge, making the initial adoption feel somewhat more difficult. Especially for short-duration measurements or spot surveys, the convenience of network RTK—where correction information is available as soon as you power on—stands out.

On the other hand, depending on the operational scenario, the own base station method can be more suitable and feel “easier.” For example, in deep mountain surveys where there is no communication infrastructure, preparing your own base station is the only practical solution and thus the simplest option available. Also, if you survey the same site almost daily, once you install and fix the base station you can secure stable accuracy on your own; repeated use improves efficiency and can feel easier over time. Ultimately, which method feels easier depends on the operating environment and objectives.

Overall, network RTK wins on “ease of initial setup and configuration,” while own base stations win on the “freedom to operate anywhere regardless of communication environment.” Which one feels easier for your company depends on site conditions, operating costs, and the level of accuracy management required. Below is a summary of cases suited to each method.

Own base station method is suitable when:

• Surveying in areas without cellular coverage or in mountainous regions where Internet connectivity cannot be expected

• Long-term, large-scale projects where repeated surveys in the same area require stable in-house reference control

• Operating multiple survey instruments and it is judged more economical to provide your own base station than to pay for multiple service subscriptions

• Your company has surveying expertise and can manage equipment handling and reference point control internally

Network RTK is suitable when:

• You want to perform agile surveying in urban or plain areas with cellular coverage (you can receive corrections while moving)

• You want to keep surveying equipment minimal and introduce RTK quickly even as a first-time user

• You need to save setup time for short-term jobs, inspections, or spot surveys that require high accuracy

• You survey multiple sites spread over a wide area where one base station cannot cover all sites

Both methods have pros and cons, but today the prevailing approach is often: “start easily with network RTK, and consider your own base station as needed.” Use services at first to build know-how, and when usage frequency rises and economic or operational benefits of self-operation become clear, introduce your own base station as a second step.

Simple Surveying with LRTK

As described above, RTK normally requires either installing your own base station or contracting with an external network service, but recently new approaches have emerged that further reduce these burdens and make high-precision positioning simpler. One such system is called LRTK. LRTK is a smartphone-integrated positioning solution that aims to eliminate specialized surveying equipment and complex settings as much as possible, allowing “anyone to easily handle cm-level positioning.”

LRTK combines a dedicated small GNSS receiver with a smartphone app to achieve RTK-level high-precision positioning via simple procedures. For example, a receiver attached to a smartphone can be held in one hand and by pressing a button at the point to be measured, the high-precision coordinates of that point can be obtained. It enables vertical positioning not possible with standard GPS, and errors are about horizontal ±1–2 cm (±0.4–0.8 in) and vertical errors within a few centimeters (within a few inches), achieving professional surveying accuracy while keeping operation intuitive and eliminating complicated settings and adjustments typical of conventional RTK equipment.

Unlike conventional RTK, LRTK users do not need to prepare their own base station or subscribe to an external correction service. Behind it are proprietary algorithms that utilize cloud correction data and positioning information from multiple points to achieve high accuracy even with a single receiver. Acquired coordinates can be converted on the spot to Japanese geodetic coordinates and displayed on a map, and post-processing is automated. In short, even non-specialists can perform precise surveying with just a smartphone and an LRTK device.

Having examined which of the two traditional methods is easier, LRTK can be seen as a third option that removes the hassles of both. It minimizes equipment to carry, removes concerns about communications, and provides results by simply pressing a button—an ease not found in conventional methods. Of course, the optimal choice depends on use and site conditions, but for those who want to try high-precision surveying more casually, LRTK is a compelling solution. Detailed installation guides and case studies for LRTK are available, so interested readers should refer to those materials. With the power of modern technology, high-precision surveying will become more accessible.

FAQ

Q: What is the difference between RTK and regular GPS positioning? A: Standalone GPS (GNSS) positioning relies only on satellite signals and typically yields errors of about 5–10 m (16.4–32.8 ft). RTK positioning uses correction information from a base station to cancel error factors and can determine positions with centimeter-level accuracy. In short, RTK is dramatically more accurate than standalone GPS.

Q: What accuracy can be achieved with RTK surveying? A: With proper RTK operation, horizontal positions are generally within ±1–3 cm (±0.4–1.2 in), and vertical (height) accuracy is about ±3–5 cm (±1.2–2.0 in). Accuracy depends on baseline length from the base station and satellite reception conditions—errors tend to increase with distance. Obstructed environments can also reduce accuracy. Under a clear sky and with short baselines, you can generally expect errors of about 2 cm (about 0.8 in).

Q: What is needed to use network RTK? A: To use network RTK you need an RTK-capable GNSS rover and a way to connect to the Internet. Specifically, a GNSS receiver and antenna plus a communication device (a SIM-enabled terminal or smartphone) to connect to the correction service are sufficient. You also need to sign a contract with a network RTK service provider and input login ID, server information, and coordinate system settings into your receiver or app in advance. Then, power on the receiver in the field and connect via your smartphone to start receiving correction data.

Q: Are there advantages to installing your own base station? A: Yes. Installing your own base station has advantages under certain conditions: it enables RTK positioning where there is no communication infrastructure, reduces long-term costs by avoiding service fees, and allows you to manage and guarantee stable accuracy internally. However, owning a base station requires equipment costs and operational effort, so it is not suitable for everyone. Consider site conditions and usage frequency to determine whether the benefits outweigh the drawbacks.

Q: What is LRTK and how does it work? A: LRTK is a new positioning system that achieves cm-level accuracy with a small standalone receiver and a smartphone, without the need for a user-owned base station or complex communication setup. Proprietary algorithms and cloud technology allow RTK-like accuracy with the simple operation of pressing a button on a smartphone. It is intended to make RTK-style positioning easy to adopt and operate, reducing the burden of introduction and use so that non-specialists can handle high-precision positioning.