RTK vs PPK: Differences, Accuracy, and Which Is Easier On Site | LRTK

Table of Contents

• Differences between RTK and PPK and a comparison of accuracy

• RTK advantages and disadvantages

• PPK advantages and disadvantages

• Which is easier to use on site?

• Simple surveying with LRTK

• Conclusion

• FAQ

In recent years, there has been growing demand for centimeter-level high-precision positioning in situations such as construction and civil engineering quality control and autopilot systems in smart agriculture. Tasks that were traditionally performed with optical surveying instruments like total stations have also been streamlined through the use of GNSS. Furthermore, RTK/PPK technologies are used in drone (UAV) photogrammetry, enabling the creation of highly accurate terrain models. Responding to this demand, RTK (Real-Time Kinematic) and PPK (Post-Process Kinematic) positioning using GNSS satellites are widely deployed. For surveying practitioners and those considering adopting high-precision positioning technologies, understanding the differences between RTK and PPK and how to use them is important. In particular, since both methods are said to achieve nearly the same final accuracy, many people wonder, “Which one actually makes fieldwork easier?” This article compares RTK and PPK in detail from the perspectives of ease of use, immediacy, on-site efficiency, and cost-effectiveness. Finally, we introduce a new solution, LRTK, for simplified surveying. RTK/PPK are becoming indispensable across a wide range of fields, from infrastructure to agriculture.

Differences between RTK and PPK and a comparison of accuracy

RTK (Real-Time Kinematic) is a method in which the rover—a positioning receiver—and a base station installed at a known coordinate exchange correction information in real time via radio or network during positioning. Because positional errors are corrected simultaneously with measurement, highly accurate coordinates can be obtained on the spot. There is also a widespread practice of using public network-based RTK correction services over mobile networks (virtual reference station methods), eliminating the need to set up a dedicated base station on site. PPK (Post-Process Kinematic) is a method in which GNSS observation data are recorded at both the rover and the base station during positioning, and the data are matched and corrected after measurement. No real-time communication is required on site; high-precision results are obtained by post-processing the recorded data with dedicated software after returning to the office. Base station data can be recorded with your own equipment or downloaded later from public observation data such as the Geospatial Information Authority of Japan’s Continuously Operating Reference Stations.

Both RTK and PPK rely on GNSS (e.g., GPS) observation data to correct errors and achieve centimeter-level positioning. With proper operation, the achievable accuracy is very high: typically several centimeters horizontally and several centimeters to a dozen centimeters vertically. Theoretically, PPK has a slight advantage because all data can be analyzed after measurement, and RTK carries a risk of temporary accuracy degradation if communication is lost. However, under stable communication conditions RTK can maintain a high-precision “fixed solution” throughout, and there is no major difference in the final positioning accuracy obtained. In short, it is fair to say that, under appropriate conditions, both methods can achieve almost equivalent high accuracy.

RTK advantages and disadvantages

Advantages:

• Because centimeter accuracy is obtained simultaneously with measurement, you can perform on-site quality checks and progress management immediately.

• Data do not require post-processing and can be used as deliverables as-is, shortening work time.

• Real-time high-precision information can be directly used for machine guidance of construction equipment and automatic steering of agricultural machinery.

Disadvantages:

• Setting up a base station and configuring communications on site are needed, so startup procedures can be complicated.

• RTK depends on radio or network connections, making high-precision positioning difficult in mountainous areas or sites with no signal.

• If communication is interrupted during measurement, accuracy can temporarily drop from centimeter-level to meter-level, risking discontinuities in the data.

• RTK-capable high-precision GNSS receivers and communication equipment are required, and there may be additional fees for GNSS correction services, resulting in high initial costs.

As described above, RTK’s major strength is its real-time convenience, while it also faces some challenges in terms of communication environment and equipment preparation.

PPK advantages and disadvantages

Advantages:

• Unaffected by communication conditions, PPK enables high-precision surveying even in areas without signal, such as mountainous regions or wide areas.

• On-site operations are simple; you only need to set up a base station and record logs, minimizing on-site procedures.

• Post-processing allows all data to be analyzed and corrected, making it easier to stabilize final accuracy even under challenging conditions (temporary satellite reception disturbances can be compensated for later).

Disadvantages:

• Positioning results are not available immediately on site, so real-time verification or additional measurements are impossible.

• Post-processing requires time and effort and typically needs dedicated analysis software and GNSS knowledge.

• Deliverables are not finalized until data processing is complete, lengthening the overall lead time. If data issues are discovered later, you may need to revisit the site, which is inefficient.

• Depending on required equipment and software, initial costs can be comparable to RTK, so it is not necessarily always lower cost.

Thus, PPK offers on-site simplicity and high stability, but lacks immediacy and requires post-processing effort.

Which is easier to use on site?

If accuracy is the same, which method makes on-site work easier? The conclusion is that what feels “easier” depends on site conditions and the intended use. The cases in which each method demonstrates its strengths are summarized below.

Cases where RTK is suitable for on-site work:

• Tasks that require immediate accuracy verification or data use after measurement (e.g., daily as-built reporting at construction sites).

• Environments where communication with the base station can be stably maintained (within a radius of several km (several miles) from the base station with good line of sight, or sites where mobile networks are available).

• Work areas that are relatively small and can be completed in a short time.

Cases where PPK is advantageous:

• Surveying roads or rivers over several km or more (several miles or more), or conducting aerial surveys/measurements of large areas at once.

• Sites without established communication infrastructure, such as mountainous areas or remote islands, or environments with many trees or structures that may block radio signals.

• Situations where there is adequate time for post-processing and you want to verify accuracy as much as possible to ensure reliable deliverables.

Overall, communication-friendly daily tasks that require quick deliverables favor RTK for reducing on-site burden, whereas large-scale surveys in areas with poor communication favor PPK for simplifying on-site work. From a cost-effectiveness perspective, RTK can reduce labor costs by completing work in real time on site, while PPK can achieve high accuracy while suppressing equipment and communication costs in some cases. Choose the optimal method by considering total cost and effort relative to your frequency of work and site conditions. RTK and PPK are not mutually exclusive; they can be used complementarily according to field conditions. For example, you can record raw data during RTK surveys and reprocess later with PPK if needed to hedge against positioning accuracy risks.

Simple surveying with LRTK

Recently, solutions that further simplify on-site work while leveraging the benefits of RTK/PPK have emerged. One such solution is LRTK. LRTK is a next-generation compact RTK-GNSS system developed to enable “anytime, anywhere, anyone” RTK use. Traditionally, RTK surveying required bulky base station equipment mounted on large tripods or poles, plus radios and batteries, making transport and setup cumbersome. LRTK devices, however, are compact enough to fit in the palm of your hand, and models include versions that can be mounted on a dedicated helmet for walking surveys or integrated with a smartphone. For example, attaching a pocket-sized LRTK device to a smartphone enables centimeter-level positioning anytime, anywhere. Miniaturization has also drastically reduced equipment costs, lowering the barrier to adoption.

In practice, some local governments have begun experimenting with smartphone-only on-site surveying using LRTK to speed disaster recovery and reduce costs (in 2023 Fukui City introduced LRTK for disaster recovery). Technically, LRTK adopts the latest GNSS solutions to deliver both high accuracy and ease of use. LRTK devices support multiple satellite constellations such as GPS, GLONASS, and Galileo, and use multi-frequency positioning (L1/L2/L6, etc.) to reduce ionospheric errors and multipath reflections. Additionally, they support Japan’s Quasi-Zenith Satellite System “Michibiki” centimeter-level augmentation service (CLAS), enabling high-precision positioning from satellite augmentation signals alone even in mountainous or offshore areas outside mobile coverage. This allows LRTK devices to receive corrections and achieve real-time centimeter-level positioning single-handedly in locations where conventional RTK would fail due to lack of radio signal.

LRTK also offers high operational flexibility and supports both RTK and PPK modes. For example, by using two LRTK devices—one as a simple base station and the other as a rover (e.g., mounted on a drone)—you can create your own radio link and obtain centimeter accuracy in real time without existing communication infrastructure. Conversely, you can mount a single LRTK on existing surveying equipment or a drone, log data, and perform PPK processing later. These approaches make LRTK an evolved high-precision positioning terminal that any field technician can handle easily. Its adoption can dramatically improve surveying accuracy and work efficiency and contributes to the construction industry’s DX initiatives, such as the Ministry of Land, Infrastructure, Transport and Tourism’s “i-Construction.”

Conclusion

RTK and PPK both enable centimeter-level high-precision positioning, but they differ significantly in real-time capability and operational characteristics. RTK is effective when you need immediate results on site and when communications are available, while PPK excels in wide-area surveys and sites where communication is difficult. Understanding the advantages and disadvantages of each and using them appropriately or in combination according to site conditions will maximize surveying efficiency and accuracy.

For example, on one construction site, an RTK base station enables immediate daily measurements of embankment volumes, which are reflected in construction management the same day. On the other hand, in mountain road surveying, GNSS data are logged while moving and later processed with PPK to create detailed terrain maps. In agriculture, combining RTK-based tractor auto-steering and fertilizer control with PPK-based field-wide terrain measurement improves precision agriculture efficiency.

High-precision positioning technologies are evolving daily, and devices like LRTK that are easy to use without specialized knowledge have appeared recently. Going forward, we can expect even wider access to high-precision positioning in the field. Further development of satellite positioning systems and device cost reductions will likely expand RTK/PPK use cases even more.

FAQ

Q: What is the difference between RTK and PPK? A: RTK is a method that performs positioning while communicating with a base station in real time, allowing immediate high-precision positions on site. PPK records data and corrects positions afterward, so high precision can be achieved without communication, but results are available only after post-processing.

Q: Which is more accurate, RTK or PPK? A: Under appropriate conditions, both achieve nearly equivalent accuracy (on the order of several centimeters). However, in unstable communication conditions PPK may provide more stable results. Conversely, with good communication, RTK can consistently maintain high accuracy, and there is no significant difference in final accuracy.

Q: Which should I use at a site without communication infrastructure? A: PPK is suitable for sites without communication infrastructure. Since it does not require real-time communication, surveying can be conducted in mountainous or out-of-coverage areas, and high-precision results can be obtained through post-processing.

Q: What equipment and environment are required for RTK positioning? A: Basically, you need a GNSS receiver for the base station installed at a known point and a GNSS receiver for the rover. You also need a radio communication device or a mobile network connection to link the two. Alternatively, you can use correction information distributed by public base station networks (VRS, etc.) without setting up a base station on site; in that case, the rover requires internet connectivity. It is also important to know the precise coordinates of the base station in advance.

Q: How much does it cost to implement RTK or PPK systems? A: Costs vary by equipment configuration and use case, but high-precision GNSS receivers and RTK-capable drones can require initial investments on the order of several million yen. However, operational efficiencies can yield significant labor savings and good cost-effectiveness. Recently, low-cost GNSS devices (such as LRTK) have appeared, making it easier to set up high-precision positioning environments at lower cost than before.

Q: What is LRTK? A: LRTK is a compact, lightweight high-precision GNSS positioning device developed so that anyone can easily achieve centimeter-level positioning. It supports both real-time RTK and post-process PPK positioning and can receive Japan’s satellite augmentation signal (CLAS) to achieve high precision even when out of mobile coverage.

Q: For drone photogrammetry, should I use RTK or PPK? A: It depends on the target area and work environment. For relatively small areas captured in a short time or when you need immediate deliverables, RTK is appropriate. For long-distance flights or missions in mountainous areas, PPK is more reliable because it is not affected by communications and can provide stable accuracy after processing.

Q: How far can RTK positioning work? A: Generally, with your own base station, a practical guideline is within about a 5 km (3.1 mi) radius from the base station. Beyond that, correction errors accumulate and it becomes difficult to maintain accuracy. Using network-based RTK (wide-area corrections) provided by mobile carriers or similar services, centimeter-level positioning may be possible tens of km (tens of miles) away, but accuracy then depends on the wide-area network correction quality. In urban areas, RTK may be unstable regardless of distance due to signal reflections from tall buildings.

Q: How long does PPK data processing take? A: It depends on observation time and data volume, but because dedicated software can process data automatically, typical surveying data can often be processed in tens of minutes to about an hour. Even for photogrammetry software calculating positions from a large number of photos, processing time does not necessarily increase dramatically compared to RTK workflows.

Q: How can I start high-precision positioning easily? A: Traditionally, expensive surveying equipment and specialized knowledge were required, but now simplified GNSS solutions such as LRTK are available. Using these modern devices, you can introduce centimeter-level positioning without large-scale base station setup or complex communication configuration. We recommend first considering such solutions according to your company’s use cases.