Differences Between Off-the-Shelf GNSS Receivers and RTK Systems
Let’s start by clarifying how a standard, consumer-grade GNSS (GPS) receiver differs from an RTK-capable receiver.

• Difference in Positioning Error: With a standard stand-alone GNSS receiver, satellite-clock drift, atmospheric delay, and multipath can degrade horizontal accuracy to a few metres—and under poor conditions, errors may reach 10 m or more. The position jumps you notice on a smartphone or car-navigation system are largely caused by this uncertainty.RTK positioning, on the other hand, employs two receivers at once—a fixed base station and a mobile rover—and corrects the rover’s data in real time using the differential between the two signal sets. By cancelling those error sources, RTK squeezes positioning error down to roughly 1–3 cm. Tasks that would be impossible with metre-level drift—such as fully autonomous drone flights or machine guidance for heavy equipment—become safe and reliable once the error is trimmed to only a few centimetres.

• How centimetre-level accuracy is achieved: In stand-alone GNSS positioning no corrections are applied, so orbit and clock errors of the satellites, ionospheric and tropospheric delay, and signal reflections (multipath) all introduce positional drift.

• In an RTK workflow, a base station installed at a precisely surveyed point computes those errors in real time and sends correction messages (RTCM, etc.) to the rover via radio or the internet. The rover instantly adjusts its own solution with the incoming data, yielding centimetre-class accuracy.In other words, having a constantly “known” partner to compare against lets the rover subtract the errors that it could never resolve on its own. This technique—called relative positioning—is what distinguishes RTK from the stand-alone, absolute positioning produced by consumer GNSS devices.

• Differences in dedicated equipment:Traditional high-precision GNSS surveying required bringing a lot of gear to the field— a bulky fixed base-station receiver, a rover receiver mounted on a tall pole, plus separate radios, external batteries, and other peripherals.

• Up-front costs also tended to be steep, putting RTK out of reach for all but the largest contractors. Recent technological advances, however, have driven equipment to become both smaller and more affordable—so much so that pocket-sized RTK devices like the LRTK (discussed later) are now available. In other words, a positioning technology that once demanded specialized, bulky hardware can today be deployed far more easily and inexpensively.

As you can see, mass-market GNSS units and RTK-capable GNSS receivers differ markedly in both accuracy and underlying methodology. The next section explores concrete ways to upgrade your existing handheld GNSS device so it can take advantage of high-precision RTK positioning.

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How to Upgrade Your Hand-Held GNSS Receiver for RTK Precision

There are several ways to modify or upgrade an existing GNSS / GPS unit so it can operate in RTK mode. Approaches range from adding external hardware to swapping internal modules or leveraging subscription-based correction services, each with its own advantages. Below, we outline the most common upgrade paths in turn.

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Add an External RTK Module
The quickest way to boost accuracy is to attach an external RTK module to your handheld receiver. By connecting a compact RTK-GNSS unit—such as Lefixia’s LRTK—to your current GPS device, you can keep using the hardware you already own while unlocking RTK positioning. The add-on module links to a smartphone, tablet, or survey controller via Bluetooth or a serial interface, receives correction data from a base station, and applies those corrections in real time. Because all that’s required is this dedicated external device, you gain centimetre-level precision without discarding your existing investment.

With this setup, the external receiver—the white antenna mounted on the vehicle—achieves high-precision positioning via wireless links such as Bluetooth or the 920 MHz band. When NTRIP is used, correction data is downloaded through the smartphone and then relayed to the module over Bluetooth.

For example, by pairing via Bluetooth with a smartphone, the LRTK becomes a palm-sized RTK rover that receives corrections directly from a base station. On site, you can operate simply by “plug-and-play” adding such a module instead of bulky proprietary equipment, resulting in minimal cabling and great mobility. Moreover, with an external module you can share one RTK unit across multiple terminals, delivering excellent cost efficiency.

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Swapping in an RTK-Capable GNSS Module
Another option is to physically replace your receiver’s internal GNSS module with an RTK-capable one. For example, u-blox’s ZED-F9P is a multi-band GNSS module that delivers centimeter-level accuracy. Some commercial handheld GNSS terminals and drone GPS units allow you to swap out the onboard module—simply remove the old single-frequency module (e.g. a NEO-M8N) and install an RTK-capable F9P (or equivalent) in its place. This upgrade transforms your existing device into an RTK-enabled receiver.

One major advantage of swapping in an RTK-capable module is that the upgrade stays fully integrated within the device, preserving its portability and seamless form factor. Because the RTK hardware is embedded rather than tacked on, field handling becomes much more convenient. However, performing a module swap requires electronics know-how and firmware configuration, and it may void your manufacturer’s warranty. You proceed at your own risk, but if successful it can dramatically boost the accuracy of your handheld receiver.

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Using NTRIP (Networked RTK Correction Data)
NTRIP (Networked Transport of RTCM via Internet Protocol) is a method for distributing and receiving RTK correction data over the Internet. You can achieve centimeter-level accuracy without physically modifying your handheld GNSS receiver simply by subscribing to an NTRIP-enabled service.

In practice, correction streams are broadcast from government or commercial reference-station networks (e.g. CORS or national Continuously Operating Reference Stations). You use a smartphone or data terminal to receive these corrections over the Internet and feed them in real time to your GNSS receiver.

For example, you launch an NTRIP client app on your phone to pull down the RTCM corrections, then forward them via Bluetooth to your GNSS unit—instantly enabling RTK positioning on site. This lets you enjoy network-RTK performance without ever installing your own base station.

Key points for NTRIP use are ensuring reliable network coverage and subscribing to an appropriate correction service. In areas with cellular reception (and most of Japan is covered by the national reference-station network), you can easily pull corrections over LTE/4G. While some public services offer free correction streams, a paid high-precision service typically delivers the most stable centimeter-level performance.

Your equipment needs an NTRIP-capable receiver or app, but increasingly robust smartphone apps and cloud platforms make it straightforward to ingest corrections in the field and achieve RTK accuracy.

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Upgrading Your Smartphone or Tablet GPS to RTK
You can also boost the positional accuracy of your existing smartphone or tablet GPS to RTK-level precision. The typical approach is to pair an external RTK module with an NTRIP correction stream and link it to your device. For example, by attaching a Bluetooth-enabled LRTK module to your phone and using a companion app to receive network-RTK corrections, you can achieve centimeter-level positioning that the built-in GPS on your smartphone alone cannot provide.

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Example Use Case: LRTK Phone, a Compact RTK-GNSS Receiver for Smartphones
By simply mounting the ultra‐compact LRTK Phone onto the back of your iPhone via its custom case, your smartphone transforms into a centimeter-accurate surveying instrument using network-RTK corrections. Despite integrating both battery and antenna, the device weighs only 125 g and measures just 13 mm thick, yet delivers full RTK performance.

Recent innovations in smartphone-integrated RTK devices mean that each field technician can now “turn their own phone into an RTK terminal.” In tests with the LRTK Phone, positional error dropped from several meters (typical of standard smartphone GPS) to just a few centimeters merely by attaching the LRTK module.

With solutions like this, you no longer need dedicated surveying equipment to capture high-precision location data in daily operations. You can tag field photos with centimeter-level coordinates or instantly upload RTK data to the cloud for on-the-fly map creation. Equipping every team member with a “one-phone-fits-all” RTK tool will dramatically accelerate DX (digital transformation) on the job site.

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How to Make a Drone RTK-Capable
Even when using drones (UAVs) for aerial photogrammetry or infrastructure inspection, adding RTK for high-precision positioning offers huge benefits. In this section, we explain how to retrofit a commercial drone for RTK, the key differences between RTK-equipped and non-RTK models, and share a case study of drone surveying using the LRTK system.

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Adding an RTK Module to a Commercial Drone
Even off-the-shelf consumer drones can often be upgraded for RTK. For example, some higher-end DJI models offer an optional RTK module that simply snaps onto the airframe and is enabled via firmware settings. While DJI’s industrial Mavic series (e.g. Mavic 3 Enterprise) and the Phantom 4 RTK ship with RTK built in, many other drones can be made RTK-compatible using an expansion port or a third-party RTK unit.

The basic approach is to mount a compact RTK receiver on the drone and sync its corrections with the vehicle’s GNSS data. On the ground you can stream NTRIP corrections over cellular, or you can operate the drone itself as the rover by installing its RTK receiver and running a base station on the ground. The latter setup avoids extra weight on the UAV and also supports post-processing kinematic (PPK) workflows—tagging high-precision flight logs onto images after landing.

Each drone model requires its own installation steps according to the manufacturer’s instructions or published guides, but dedicated RTK modules make the upgrade surprisingly straightforward. For instance, DJI has released a video tutorial showing how to attach the genuine RTK module to a Mavic 3 Enterprise: you mount the module, pair it with the aircraft, and enter your NTRIP credentials—and you’re ready to fly with centimeter-level positioning. In this way, adding a simple hardware module can transform an existing drone into a precision surveying platform.

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Differences Between RTK-Enabled Drones and GPS-Only Drones
There are several operational distinctions between drones equipped with RTK support and those that rely solely on standard GPS.

• Reduction of Ground Control Points (GCPs):Traditional drone photogrammetry requires deploying and surveying numerous ground control points—physical markers with known coordinates—to accurately align aerial images. An RTK-equipped drone, however, embeds high-accuracy position metadata directly into each photograph. This greatly reduces or even eliminates the need for pre-installed GCPs, cutting setup time dramatically and delivering far higher efficiency compared with non-RTK workflows.

• Improved Survey Accuracy:An RTK‐enabled drone can capture position data with centimeter‐level accuracy in a mapped coordinate system without any post‐processing. For example, even when surveying large agricultural or development sites, RTK yields orthoimagery and point clouds with minimal distortion or positional shift. In contrast, non-RTK drones suffer from GPS errors that can introduce offsets of several decimeters to meters in the model, requiring additional corrections for precise volume calculations or as-built verification. By integrating RTK, the raw imagery and point-cloud accuracy is significantly higher, which also streamlines subsequent georeferencing and adjustment workflows.

• Flight Stability & Safety:High‐accuracy RTK positioning enhances the stability of drone autonomous flight. With GPS alone, accumulated errors can cause a drone to drift off its planned path during waypoint navigation, increasing the risk of deviation. RTK’s centimeter‐level position control enables safer, more precise adherence to the flight plan. This is especially critical for inspection missions conducted near structures, where even a few meters of drift could result in a collision. An RTK‐equipped drone significantly reduces that risk.

In summary, RTK‐equipped drones offer clear benefits in reduced preparation effort, improved data quality, and lowered operational risk. While the initial investment is somewhat higher, for operations that routinely perform wide‐area surveys or infrastructure inspections, this outlay delivers corresponding gains in efficiency and precision.

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Use Cases of Drone Surveying with LRTK
The LRTK device introduced earlier isn’t just for handheld use—it’s also finding applications in drone surveying. For example, one team built a low-cost RTK survey system by mounting an LRTK module on a small survey drone and streaming NTRIP corrections from a ground-based tablet. Because the LRTK is so lightweight and compact, it can be carried by small drones without affecting flight performance, and its built-in battery means wiring is kept to a minimum.

At another site, a non-RTK drone was converted into a makeshift RTK platform by equipping it with an LRTK unit as the rover and receiving electronic reference-point data from the Geospatial Information Authority of Japan via NTRIP. All captured images were automatically tagged with high-precision corrected coordinates, eliminating the need for post-flight geotagging. In a different case, operators used the LRTK’s centimeter-level position data to display the drone camera’s capture points in AR, filling in point-cloud data behind structures that couldn’t be seen directly. These creative setups demonstrate that LRTK can serve as an affordable, flexible solution in drone surveying.

As integration between drones and LRTK advances, more teams will be able to achieve RTK-equivalent accuracy without replacing their existing UAVs or renting costly RTK-equipped models. Conducting a pilot deployment in your own operation can be a great way to evaluate its potential benefits.

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Cost, Accuracy & Implementation Difficulty by Upgrade Method
Finally, let’s compare each upgrade method introduced above in terms of initial cost, achievable accuracy, and ease of implementation. Use this comparison as a guide to select the most suitable approach for your field requirements.

For example, “add-on RTK modules” are well suited for retrofitting existing handheld GNSS units or total stations, while “module replacement” is effective for boosting the accuracy of in-house devices or open-source GNSS receivers.“Using NTRIP” is especially convenient for survey teams working across Japan who need high-precision positioning without installing their own base station, while “smartphone RTK support” is ideal for site supervisors or inspectors who require high-accuracy data on a daily basis. Equipping drones with RTK delivers powerful performance for large-area surveying projects.In this way, by taking into account factors such as the scale of the site, the required level of accuracy, and whether it will be used in conjunction with leveling surveys, choose the most appropriate method.

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Introduction to LRTK
Finally, let us introduce LRTK, one of the latest compact, lightweight, high-precision RTK upgrade products. Developed around the concept of “anyone, anywhere, anytime can leverage RTK,” LRTK is a next-generation RTK-GNSS solution. Here are some of its key features:

• Compact, All-in-One Design: LRTK integrates battery, antenna, and receiver into a single compact unit. For example, the smartphone-mounted LRTK Phone fits into a custom phone case, delivering pocket-sized portability on site. Variants such as helmet-mounted units and a fixed “Pro” model are also available, allowing you to choose the form factor that best suits your application.

• High-Precision, Highly Reliable Positioning: Equipped with a state-of-the-art multi-band GNSS receiver, LRTK supports not only GPS but also GLONASS, Galileo, BeiDou, and Japan’s QZSS (Michibiki). Its triple-frequency capability makes it resilient against multipath and ionospheric errors, facilitating stable RTK Fixes. Some models even receive Michibiki’s CLAS centimeter-level correction signals, allowing true centimeter-accuracy directly from the satellites—even in mountainous or offshore areas with no cellular coverage.

• Ease of Use & Integration: One of LRTK’s most compelling features is its simplicity compared to traditional RTK systems. No specialized training is required—just pair it with your smartphone over Bluetooth, tap “Start Positioning” in the dedicated app, and you’re up and running. Correction sources (NTRIP, CLAS, etc.) are all configurable with a single tap. Position data streams live to the cloud for instant sharing between the field and the office. Designed so that field engineers can operate it as intuitively as a smartphone, LRTK truly “democratizes” high-precision GNSS positioning.

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Thus, the LRTK is a field-honed, high-precision instrument that combines the best of standalone GNSS and RTK. By deploying it, you can streamline and elevate a wide range of workflows—from surveying through construction management. In fact, in Construction ICT and infrastructure maintenance operations, its ability to turn a smartphone into a full-blown surveying instrument has made it a game-changing asset for on-site digital transformation.