How to Increase RTK Fix Rate: Practical Techniques That Work on Site

Table of Contents

• Introduction

• Optimizing Satellite Geometry (Reducing GDOP)

• Thorough Multipath Countermeasures

• Keep an Appropriate Distance to the Base Station

• Verify the Quality of Correction Data

• Avoid Radio Interference

• GNSS Antenna Installation Tips

• Measurement and Operational Techniques

• Use of High-Precision Equipment and Settings

• Real-Time Verification of Positioning Accuracy

• What to Do When You Can’t Get a Fix

• Recommendation: Simple Surveying with LRTK

• FAQ

Introduction

RTK positioning (Real-Time Kinematic) is an essential technology that enables real-time, centimeter-level high-precision positioning for surveying and construction sites. In particular, obtaining a high-precision Fix solution with RTK dramatically improves the efficiency and reliability of field tasks such as as-built control and infrastructure inspection. However, in actual fieldwork, various factors—such as radio signal reflections called multipath, biased satellite geometry, communication delays, and radio interference—often combine and make it difficult to obtain a reliable Fix solution.

This article explains practical points in detail to increase the RTK fix rate (the proportion of times a Fix solution is obtained) that are useful on site. Covering basic countermeasures such as satellite geometry and environmental preparation, through optimization of device settings and responses when problems occur, this guide compiles techniques that even beginners can apply. Please use it as a reference to reliably obtain Fix solutions and maximize the potential of RTK positioning.

Optimizing Satellite Geometry (Reducing GDOP)

One major factor that affects RTK accuracy and the ease of obtaining a Fix is the satellite geometry—how satellites are distributed in the sky. If the satellites used for positioning are clustered in a particular direction, the geometric strength is weak and the GDOP (Geometric Dilution of Precision) value becomes large. A large GDOP leads to increased positioning error and makes it difficult to obtain a stable Fix. Conversely, when satellites are well distributed across the sky, the geometry is strong and GDOP is kept low.

Therefore, when deciding the date/time and location for surveying, it is effective to simulate satellite geometry in advance using a GNSS planner and aim for time windows with low DOP values. Recent high-precision GNSS receivers support not only GPS but also GLONASS, Galileo, and QZSS (Michibiki)—i.e., multi-GNSS—and increasing the number of usable satellites tends to lower DOP and improve fix rate. Additionally, avoid setting the receiver’s elevation mask (which excludes low-elevation satellites) excessively high. Setting the elevation mask to around 15° and using low-elevation satellites in balance can be advantageous for both satellite count and geometry, making it easier to obtain a high-precision Fix.

Thorough Multipath Countermeasures

In urban high-rise areas or near rock faces in mountainous regions, signals from satellites are easily reflected by buildings and the ground, causing the multipath phenomenon, which is a major enemy of RTK positioning. Reflected signals arrive later than direct signals, causing range measurement errors, hindering Fix acquisition and degrading accuracy. To prevent this, it is important to improve the surrounding environment where you perform positioning. Choose a location with as much open sky as possible and away from surfaces that cause reflections, such as building façades, metal fences, or large vehicles. If working near buildings is unavoidable, install the GNSS antenna as high as possible to reduce the impact of reflected waves. If available, attaching a ground plane (metal plate) to the antenna can block reflections coming from the ground or from below. Some high-performance GNSS antennas and receivers include multipath mitigation functions, but the basic principle is to create an environment that minimizes reflections. Additionally, appropriately set the elevation mask mentioned earlier, and consider excluding low-angle satellite signals that are prone to reflect from the ground or buildings (for example, signals below 15°). Thorough application of these measures ensures a lower-noise environment and leads to more stable Fix acquisition.

Keep an Appropriate Distance to the Base Station

Because RTK improves accuracy via relative positioning between a base station and a rover, if the distance between the base and rover (the baseline length) is too long, accuracy and fix rate decrease. This is because uncorrectable differences in ionospheric delay, tropospheric errors, and other effects grow with the differing signal paths between the two stations. In practice, a baseline length of within 10 km (6.2 mi) is considered ideal, and beyond this the time to obtain a Fix tends to increase and stability can suffer. If possible, install your own base station close to the work area. If that is difficult, use nearby electronic reference points or VRS (Virtual Reference Station) services provided by national agencies, local governments, or private companies. With network RTK (NTRIP services) using a VRS method, a virtual base station near the user can be generated, effectively keeping the baseline to a few kilometers. Keeping the baseline short reduces differential errors between the stations and, as a result, makes it faster and easier to obtain a stable Fix.

Verify the Quality of Correction Data

When using network RTK, the quality of the correction data received over the Internet (e.g., data streamed via NTRIP) directly affects fix rate. First, confirm that the type of correction data you use matches your rover receiver. For example, a single-frequency (L1-only) receiver requires data streams for single-frequency use (e.g., RTCM MSM4), whereas a multi-frequency receiver needs MSM7 or streams containing higher-precision information that cover all frequencies. If you can choose among multiple base station networks or correction services, select correction data that is close to your positioning location or a service with a proven track record for greater stability. In addition, the NTRIP connection’s communication status is important: when using mobile data or pocket Wi-Fi, connect in areas with good signal strength and take care to avoid communication delays or dropouts. Large time lags in correction data can destabilize the Fix or degrade it to a Float solution. Make it a habit to check the receiver or app’s status screen for Age of Differential and RTCM message reception status to ensure corrections are arriving in real time. If needed, switch NTRIP mount points or change the communication line to maintain high-quality correction data reception.

Avoid Radio Interference

RTK deals with very weak satellite signals, so be attentive to interference noise from strong surrounding radio sources. For example, high-voltage power lines can generate strong electromagnetic fields that affect GNSS reception. Radio transmissions used on construction sites, nearby Wi‑Fi routers, and cellular base stations can also infiltrate the receiver and act as noise sources. The basic countermeasure is to position measurements as far as possible from strong noise sources. Avoid working directly under power lines or near broadcast towers for TV and radio. If you must work in such environments, consider using a noise filter that can be attached to the receiver. You can also reduce interference by changing rover settings—turn off unused wireless functions (Bluetooth or built-in radios) and keep other electronic devices at a distance. Choosing an electromagnetically clean environment is the quickest way to obtain a fast, reliable Fix.

GNSS Antenna Installation Tips

Did you know that RTK accuracy and Fix stability can change depending on how the GNSS antenna and receiver are installed? First, always install the antenna level so it is not tilted. A tilted antenna can create reception bias and potentially introduce biased errors into positioning results. When using a tripod or pole, use a bubble level to ensure it is truly horizontal. Antenna height is also important. Placing an antenna close to the ground increases susceptibility to ground reflections and increases shielding from nearby objects. Mounting the antenna on a sufficiently tall pole (approximately 1.5-2 m (4.9-6.6 ft)) improves visibility and reduces noise sources. However, attaching the antenna to the tip of a long, slim pole risks wind-induced sway, so secure it firmly with brackets. In strong winds, consider installing lower rather than using an excessively long pole. If you set up your own base station, calibrate it beforehand at known points to ensure the correct coordinates are set (base station coordinate error directly impacts rover results). Also be sure to measure and record the antenna height accurately when installing. These basic installation practices remove unnecessary error sources and help maintain RTK Fix accuracy.

Measurement and Operational Techniques

To reliably obtain an integer Fix solution on site, proper measurement procedures and operational tips are as important as device handling. First, after starting positioning, do not move immediately; wait tens of seconds for satellite signal acquisition and correction data reception to stabilize. Keep the antenna stationary until you see a Fix solution, and only then begin moving. If you start walking immediately after initializing, you may record position data while the solution is still Float and unstable, leaving inaccurate results.

For static measurements, maintain the Fix at a single point for a sufficient period (sometimes tens of seconds or more) and use the app’s averaging function to record averaged values during that time to further improve accuracy. For kinematic or continuous mobile surveying, if the Fix is lost and reverts to Float, positional data recorded during that interval will not be high-precision, so be cautious. Even during mobile surveying, stop briefly at important points and wait until the receiver returns to Fix status before recording positions. Prior to measuring, warm up the receiver to check satellite reception, and if signal conditions are poor, slightly move the antenna to try to improve reception—this kind of preparation is effective. If Fix becomes unstable during measurement, a full reset (reacquiring correction data or restarting the receiver) can help. Always enforce the practice of recording data only when a stable Fix is being obtained to maximize the potential of RTK positioning.

Use of High-Precision Equipment and Settings

The performance and settings of the GNSS equipment you use greatly influence RTK fix rate. Using a high-quality multi-frequency GNSS receiver significantly speeds ambiguity resolution compared to single-frequency receivers, shortening time to Fix and improving stability. Receivers that support multiple satellite systems in addition to GPS naturally increase the number of usable satellites, improving geometry and reducing the risk of signal loss. Optimize various receiver and app settings as well—for example, base station data format settings, selection of positioning mode (static/kinematic), and filtering options—following the manufacturer’s recommended values to extract expected performance. Keep firmware and apps up to date to take advantage of new satellites and algorithm improvements.

Recently, high-precision GNSS devices designed to connect to smartphones and tablets have become widespread. By linking with a phone via Bluetooth or Wi‑Fi and using a dedicated app to intuitively set corrections and record logs, these devices are easier for inexperienced users to operate. They also make on-site data verification simple, providing real-time information useful for maintaining Fix (such as satellite count, DOP, Fix/Float status). Review your device’s settings once and create an optimal profile so that surveying runs smoothly during actual work.

Real-Time Verification of Positioning Accuracy

With RTK, it is important to judge the quality of the obtained position data on site as you work. If you only notice back in the office that the accuracy was insufficient, it’s already too late—so make it a habit to continuously check data reliability during surveying. The basic check is to look at the receiver or app display for the solution type. A displayed status of “FIX” is the prerequisite for high-precision positioning; “FLOAT,” “DGNSS,” or “SINGLE” indicate lower accuracy. Keep an eye on whether you are consistently getting a Fix, and if you fall into Float, immediately remove the cause (for example, move away from obstructions or reacquire correction data).

Monitoring DOP is also indispensable. The horizontal DOP (HDOP) is generally considered high-precision at 2.0 or lower, acceptable around 2–5, and a cause for concern above 5. If HDOP or PDOP temporarily increases significantly during measurement, it may be necessary to pause and wait for satellite geometry to improve. If known reference points or stake points with accurate coordinates exist on site, perform a trial measurement there to check errors—a “known-point verification” is an effective method. If repeated measurements at the same point differ by several centimeters, some problem may exist in the system or environment. For important points, observe them multiple times at different times and compare coordinates; if the same point yields differences of 5 cm (2.0 in) or more between two measurements, it is a sign you should recheck data quality. When recording data, also save logs such as date/time, positioning mode, and satellite counts so you can analyze issues later if they arise.

What to Do When You Can’t Get a Fix

Even with thorough preparation, field conditions may sometimes prevent obtaining a Fix or the Fix may collapse quickly. To handle such situations calmly, keep the following checkpoints in mind.

• Check satellite reception: Confirm that the number of available satellites is not extremely low and that there are no directions with weak signals. Look around the antenna for obstructing buildings or obstacles and avoid them if possible. In some cases, moving the antenna just a few meters can capture additional satellites and improve the situation.

• Check correction data reception: If receiving correction data via NTRIP, verify that the connection is not dropped and that there are no issues at the base station. Fix cannot be obtained without correction data, so try restarting smartphone tethering or the mobile router, or move to a place with better signal. Even if correction data is arriving, errors can occur if the base station coordinates are set incorrectly or the chosen coordinate reference frame does not match. If using your own base station, double-check the configured coordinates and compare with an official reference point if necessary.

• Reset receiver or software settings: Temporarily stop RTK, reset receiver settings, and try again. Switching positioning mode to Single and then back to RTK, restarting the receiver, or trying a different correction method (for example, switching to QZSS CLAS satellite correction if the Internet is unstable) may resolve the situation.

• Consider hardware faults: Physical issues such as a broken antenna cable or loose connector can prevent Fix acquisition. For cable-connected receivers, reseat all connections and clean connector contacts. If the problem persists, try another antenna or receiver.

• Change location or time: If none of the above works, as a last resort change your measurement location substantially. Moving to a more open location often results in an immediate Fix. Changing the time of day can also improve satellite geometry or ionospheric conditions and lead to a Fix.

The important thing is not to wait aimlessly but to isolate causes and take measures promptly. Prepare multiple fallback options so you don’t get stuck on site insisting on a Fix—this will let you respond calmly in critical moments.

Recommendation: Simple Surveying with LRTK

The above described various points to increase RTK fix rate, but perfect on-site implementation of all these measures requires some experience and know-how. Recently, as a solution that makes advanced RTK positioning easier to use, simple surveying with LRTK has attracted attention. The LRTK series provided by Lefixea Inc. is a state‑of‑the‑art RTK-GNSS system designed to be easy for field technicians to use. Its greatest strengths are the threefold advantages of “compact and lightweight,” “easy operation,” and “high precision.”

• Compact and lightweight: Conventional high-precision GNSS gear, including antennas and large batteries, tended to be bulky, but LRTK terminals are smartphone-sized and weigh just a few hundred grams. For example, the integrated smartphone model LRTK Phone features an ultra-compact design weighing approximately 125 g and a thickness of 13 mm (0.51 in), developed as a one-person-per-device surveying tool attachable to an iPhone. This portability means it can be carried on-site without burden and used instantly when needed.

• Easy operation: The LRTK series is operated intuitively via a dedicated smartphone app. Connect the receiver to your phone via Bluetooth or Wi‑Fi and follow the app prompts to complete GNSS settings. On site, simply power on and tap the “Start Positioning” button on the smartphone to obtain centimeter-level positioning immediately. It also provides one-stop functionality such as automatic geotagging of photos, 3D scanning, and AR-assisted staking, lowering the barrier to civil engineering surveying even for those without specialist knowledge.

• High precision: Crucially, positioning accuracy is excellent; under good conditions the system consistently yields centimeter-level Fix solutions. Higher-end LRTK Pro series models support CLAS satellite correction signals from Japan’s QZSS (Michibiki), enabling high-precision positioning via satellite corrections even in mountainous areas without Internet connectivity. Some models also include tilt compensation, which automatically corrects the tip position when the pole is slightly tilted, making surveying effective even where a vertical pole cannot be used due to obstacles.

By leveraging LRTK in this way, RTK positioning—which once relied heavily on expert knowledge—is becoming accessible for anyone to perform high-precision surveying. Because the system optimizes complex settings and environmental adjustments internally, users can concentrate more fully on fieldwork. If interested, please also visit the [LRTK series official site](https://lefixea.com) to check out how simple surveying with the latest technology works.

FAQ

Q1: What do “Fix” and “Float” in RTK mean? A: In RTK positioning, a “Fix solution” means the integer ambiguity (based on carrier phase differences received from satellites) has been correctly resolved—an integer-fixed solution. In simple terms, this indicates a high-precision position typically within a few centimeters. On the other hand, a “Float solution” is a state where ambiguities are unresolved; the solution is unstable and errors can be on the order of several tens of centimeters. For high-precision fieldwork, always confirm the receiver’s status shows “FIX” and wait for the solution to converge to Fix when it is Float.

Q2: What are common causes for RTK not achieving Fix easily? A: Common causes include: (1) insufficient satellite visibility due to tall buildings or trees, (2) signal degradation from multipath reflections off metal structures, (3) baseline distance to the base station being too long for corrections to keep up, (4) correction data not being received properly, and (5) strong radio interference. Applying the countermeasures discussed in this article (moving to open sky, raising the antenna, reviewing correction data and settings, etc.) often improves fix rate.

Q3: How long does it usually take to get a Fix? A: Under good conditions, a Fix is often obtained within a few seconds to a few tens of seconds after powering on the RTK receiver. The latest multi-frequency receivers have faster initialization and can sometimes Fix within 10 seconds. However, poor satellite reception conditions or long baseline distances may mean Fix takes several minutes. If Fix does not occur within 1–2 minutes, examine environmental factors and apply the troubleshooting steps described. Also, if a previously obtained Fix is lost, the receiver can often reacquire Fix quickly once conditions improve.

Q4: Can a single-frequency (L1-only) GNSS receiver get a Fix? A: Single-frequency (L1-only) RTK receivers can obtain Fix solutions, but compared to multi-frequency receivers they generally take longer to reach Fix and are more prone to reverting to Float. This is because single-frequency receivers cannot mitigate ionospheric errors using multiple frequencies, making them less favorable especially at greater distances from the base station. In practice, L1-only receivers can achieve Fix on short baselines with little obstruction, but for professional surveying and stable centimeter-level accuracy, using a receiver that supports multiple frequencies (e.g., L1/L2) is recommended.

Q5: Is centimeter-level positioning possible with a smartphone? A: With current general-purpose smartphones (built-in GNSS chips) alone, achieving centimeter-level accuracy is difficult. Built-in smartphone GNSS is typically designed for meter-level accuracy, and integration with RTK corrections is limited. However, by combining a smartphone with an external high-precision GNSS receiver, centimeter-level positioning is possible. For example, a smartphone-mounted RTK receiver like the LRTK Phone can receive real-time corrections via the phone’s app and obtain high-precision Fix solutions. Using the smartphone as a display and controller while relying on dedicated hardware for positioning achieves a good balance of convenience and accuracy.