Five Basic GNSS Knowledge Items for Solar Power Plant Surveying

Contents

• First, correctly understand what GNSS is

• Understand the differences in positioning methods and choose the use appropriate for your purpose

• Know the situations where GNSS is useful in solar power plant surveying

• Grasp on-site conditions and error factors that affect accuracy

• Establish operational rules before and after introduction to stabilize survey quality

• Summary

First, correctly understand what GNSS is

The use of GNSS in surveying for solar power plants is increasing year by year. It used to feel like it was only used for specialized tasks, but now it is becoming easier to use across a wide range of processes such as checking land development plans, installing control points, confirming racking positions, and assessing as-built conditions. Therefore, as a site person in charge, it is important not only to know the device names but to understand what GNSS technology actually does. Mastering the basics makes conversations with surveying companies smoother and improves your ability to interpret deliverables and make on-site judgments.

GNSS is a general term for satellite positioning that obtains positions by receiving signals transmitted from artificial satellites. It is widely known as a system for measuring positions, but in practice it does more than just tell you the current location. Because latitude, longitude, and height can be handled as numerical values, GNSS directly supports surveying tasks such as understanding site shape, managing coordinates of measured points, and checking designs. In wide-area sites like solar power plants where managing plots and equipment positions is important, the strength of GNSS in efficiently handling large areas becomes especially evident.

An important point here is that GNSS and the commonly heard GPS are not exactly synonymous. GPS is one satellite positioning system, and GNSS is the collective term that includes it. Actual surveying equipment uses signals from multiple satellite systems to increase the number of receivable satellites and achieve more stable positioning. This is especially important in locations where sky visibility is inconsistent, such as near ridgelines or on developed slopes—having access to more satellites affects positioning stability. Candidate sites and construction areas for solar power plants can include not only flat land but also slopes and valley terrain, so this consideration is very important in practice.

Also, GNSS is not omnipotent. Because it uses satellites, there are prerequisites such as having a sufficiently open sky, a stable reception environment, and appropriate availability of correction information. In other words, bringing equipment to any location does not guarantee the same accuracy everywhere. That is why you need to consider not only device performance but also the surrounding environment, work procedures, and verification methods on site. The first step in correctly understanding GNSS is to view it not as a convenient gadget but as a surveying technology that delivers high benefits only when conditions are met.

In surveying for solar power plants, you want to grasp large areas quickly while design and construction require fine positional accuracy. GNSS is a very effective means to reconcile these two needs. However, to maximize its effectiveness you must understand the meaning of coordinates, the mechanism of positioning, and the relationship with site conditions, and choose the appropriate method for each use. Recognizing GNSS as a foundational technology that supports planning and construction of solar power plants, rather than just a tool for position checking, is the starting point for practitioners.

Understand the differences in positioning methods and choose the use appropriate for your purpose

One of the most important basic pieces of knowledge when using GNSS on site is the differences in positioning methods. Even when using the same satellite signals, the chosen method for determining position greatly affects achievable accuracy, work speed, necessary preparation, and suitable tasks. In solar power plant surveying there are tasks that require quickly grasping a relatively wide area, such as terrain checks, and tasks that require high accuracy, such as setting control points or construction positions. If you operate without understanding the differences in methods, you may spend more time than necessary or proceed with inadequate accuracy.

The simplest method is standalone positioning. This determines position using only the received satellite signals. It is easy to use to find the current location but often lacks sufficient accuracy for surveying purposes. It is suitable for on-site reconnaissance or rough checks that aim to grasp general positional relationships, but it is often not usable as-is for managing construction positions such as racking or pile centers. Standalone positioning is convenient but should not be considered a method that can cover all surveying processes.

More important in practice are positioning methods that use correction information to improve accuracy. A representative method is real-time correction positioning, which can enable centimeter-level (half-inch level) position accuracy in some situations. Because you can obtain measurement points while moving across a large site, this method is highly effective for terrain assessment before and after development, staking based on design coordinates, and as-built verification. Solar power plants often have long, expansive plots and require measuring multiple points continuously in a short time, so real-time correction-based operations suit these sites well.

On the other hand, methods that assume stricter control point management or post-processing observation may be more suitable in some cases. For example, if you want to increase the reliability of control coordinates via long-duration observation, or if the communication environment is unstable and real-time corrections are difficult to use, different operational methods may be selected. Although real-time operation tends to be preferred in the fast-paced construction of solar power plants, if the concept of control points is ambiguous, subsequent staking and as-built verification can propagate misalignments. It is important to understand that opting for a faster method and correctly establishing control points are separate issues.

When choosing a positioning method, consider not only the required accuracy but also operator skill level, communication means, availability of correction information, and site masking conditions. For instance, in mountainous sites with unstable communications, a theoretically high-accuracy method may not perform well in practice. Conversely, in an open developed site with good communications, you can efficiently carry out high-precision surveying. Do not choose a positioning method based solely on specification numbers; judge whether it can be realistically reproduced on site—this perspective is especially important in solar power plant surveying.

As a practitioner, what you should keep in mind is not which method is superior but which method is suitable for each task. The required accuracy and speed differ at the stages of site reconnaissance, design checking, and construction management. Deciding on GNSS usage after organizing these differences makes it easier to plan surveys without excess or deficiency. Understanding the differences in positioning methods helps you assess the validity of survey deliverables and reduces unnecessary rework and overlooked checks.

Know the situations where GNSS is useful in solar power plant surveying

In solar power plant surveying, how much you can concretely imagine the situations where GNSS is helpful greatly affects its introduction benefits. Merely knowing the word GNSS is not enough—you need to know in which processes its use brings efficiency and in which tasks it should be used alongside other methods. In practice, it is important to consider the flow from site reconnaissance to design, construction, and as-built verification. Solar power plant construction is not the installation of a single piece of equipment at points but the planned development of a wide area while managing numerous equipment positions, so there are many situations in which GNSS’s strengths are advantageous.

One of the first areas where GNSS is effective is early-stage site assessment. If you can capture the site boundary, existing roads, slopes, drainage directions, level differences, and surrounding structures with coordinates, you can better organize assumptions for design studies. This is especially effective when there are discrepancies between drawings and actual site conditions or when prior development has created a complex current state; simply walking the site and measuring key points can be useful. In solar power plants, small differences in elevation or the placement of pathways can affect equipment layout and constructability, so accurately capturing current conditions in the early stages contributes to stability in subsequent processes.

Next, establishing control and management points is crucial. If positional references are ambiguous during construction, misalignments can accumulate across multiple trades—racking, piles, fencing, drainage facilities, and cable routes. Having a coordinate-based reference that can be shared across the entire site using GNSS makes it easier to coordinate each task. Because solar power plant sites often extend long distances, relying on a single control point can lead to errors and communication mistakes, so the advantage of coordinate-based management is significant. The ability to link design drawings and the site using the same reference is a major value of GNSS utilization.

During construction, GNSS becomes highly convenient for staking and verification tasks. For example, when working continuously over a wide area—such as establishing row reference positions, confirming equipment placement, or checking positions of pathways and perimeter facilities—the ability to measure while moving is beneficial. Of course, you should not complete everything using only GNSS; it is essential to cross-check with other surveying instruments or existing references when necessary. Still, being able to immediately confirm coordinates and positional relationships on site is a major advantage for layout checks and progress management over wide areas.

As completion approaches, GNSS is also effective for as-built documentation and record-keeping. If you can manage post-development terrain checks, differences from design, and equipment placement records with coordinates, it makes inspections and handovers easier to explain. For solar power plants, maintenance management becomes important after completion, so organizing where equipment is located in coordinate terms has long-term value. Considering operations after commissioning, position information obtained with GNSS holds more value than mere construction records.

At the same time, it is equally important to know the situations where GNSS is not suitable. In locations with obstructed sky views, heavy multipath, or where detailed dimensional checks take priority, other methods may be more appropriate. Although solar power plant sites are generally easy to use GNSS on, careful judgment is required near slope toes or close to structures. In other words, GNSS is a highly effective tool within solar power plant surveying, but it is not universal; it is most effective when you organize its role by process.

Grasp on-site conditions and error factors that affect accuracy

An unavoidable topic when using GNSS in practice is understanding the site conditions that affect accuracy. In solar power plant surveying, a major advantage is the ability to measure large areas efficiently, but conversely, positioning results can become unstable due to environmental conditions. Do not be reassured by survey numbers alone; it is important to consider under what conditions those numbers were obtained. Especially for staking and as-built verification directly tied to construction, the level of quality control depends on whether personnel understand error factors.

The most basic condition is sky visibility. GNSS determines position by receiving signals from satellites, so the more open the sky, the better. Although prospective solar power plant sites are often open, surrounding trees, slopes, the top of embankments, temporary structures, and existing constructions can bias the number and geometry of receivable satellites. Even if positioning does not stop, stability can decrease and results at the same location can vary by time of day. Do not assume that a large site guarantees acceptable results—be aware of reception conditions at each survey point.

Next, be aware of the effects of signal reflection. If satellite signals are received after reflecting off surrounding objects rather than directly, position calculations can be disturbed. Metal temporary materials, vehicles, fences, and building facades near the measurement location can have more impact than they appear. On solar power plant sites, temporary structures and material layouts change as construction progresses, so conditions at the same site may vary over time. A location that was stable before may become unstable after moving a storage area, so avoid treating site conditions as fixed.

Correction information and communication environment also strongly affect accuracy and workflow. When performing high-precision real-time positioning, stable reception of correction information is a prerequisite. In mountainous areas or wide undeveloped land, communication conditions may vary, causing interruptions or the need for reinitialization. If operators focus only on on-screen numbers, they may continue observations without noticing communication disruptions. On expansive construction sites like solar power plants, it is essential to understand communication conditions by location in advance and determine the range where stable operation is possible.

Human factors must not be overlooked. Pole tilt, input mistakes for antenna height, insufficient observation time, and omission of verification procedures—errors in basic operations directly translate into coordinate errors. While GNSS enables efficient work, that speed can lead to skipping checks. On solar power plant sites it is common to acquire many points continuously, so if each observation is handled carelessly, systematic offsets may only be discovered later. Even with high-performance equipment, poor operational discipline undermines quality. In practice, operational accuracy is as important as device accuracy.

You cannot eliminate errors completely, but understanding the conditions that tend to produce them can greatly reduce risk. Basic practices include checking sky visibility and nearby reflective objects before observation, confirming correction information and communication status, performing re-observations or cross-checks at key points, and periodically verifying consistency with control points. To safely leverage GNSS in solar power plant surveying, pursue more than just convenience—understand where errors are likely to arise and establish an operational system that allows on-site judgment.

Establish operational rules before and after introduction to stabilize survey quality

To leverage GNSS in solar power plant surveying, how you establish operational rules is more important than simply introducing equipment. Even if a device is convenient to use on site, results will not be consistent unless it is decided who uses it, by which standards, at what timing, and what checks are performed. Solar power plants commonly involve interlinked processes—design, land development, racking, electrical work, and landscaping—so ambiguous handling of positional information readily reveals discrepancies between processes. If you introduce GNSS, consider it not merely as a labor-saving tool but as a mechanism to stabilize survey management across the entire site.

The first thing to standardize is the reference system. If it is unclear which coordinate system to manage in, where to place control points, or which reference the site drawings and data should use, then no matter how accurately GNSS measures, comparisons with design values cannot be correctly made. In solar power plants the terrain often changes before and after development, and provisional and formal references can easily coexist. Therefore, it is essential that all parties share the same reference and that handling of updates is clearly defined.

Next, standardize observation procedures. If pre-observation checks, in-observation decision criteria, and post-observation recording methods vary by person, results will differ even when using the same equipment. For example, decide in advance what level of stability is required to accept observation values, when to re-observe, and how to perform checks at key points. Because work on solar power plant sites tends to prioritize schedule, reliance on individual experience leads to skipped verifications during busy times. That is why rules that ensure consistent quality regardless of the operator are necessary.

Considerations for data management are also important. Coordinates obtained by GNSS should not end as on-site checks; they need to be organized so they can be reviewed later. If you can trace point names, acquisition times, observation conditions, and links to relevant drawings and processes, it becomes easier to respond when rework or inquiries arise. Solar power plant projects tend to generate many measurement points, and as the project progresses the value of records increases. Considering post-completion maintenance and additional work, it is important not to treat positional information as ephemeral site notes.

Furthermore, do not depend solely on GNSS for decisions. While GNSS’s attractiveness lies in its efficiency for wide areas, this can lead to overconfidence. Confirm critical positions by other methods, periodically review consistency with control points, and apply stricter observation criteria in locations with questionable visibility. In solar power plant construction, a single misalignment can propagate along the same row or block, so you need an operating approach that can detect anomalies early. Because GNSS is convenient, retaining verification mechanisms is key to stable quality.

When practitioners understand GNSS, there is a significant advantage even when outsourcing surveying. It becomes easier to specify what accuracy is required, what to focus checks on, and what deliverables are needed. Conversely, if you request surveying without that preparation, you may end up with surveys that are complete but impractical for site use. To make the most of GNSS in solar power plant surveying, design operations that include not only device performance but also standards, procedures, records, and verification workflows. Doing so is the quickest way to stabilize schedule, quality, and reproducibility.

Summary

As basic GNSS knowledge for solar power plant surveying, first understand that GNSS is a general term for satellite positioning and that it is a technology capable of efficiently handling positional information over large sites. Beyond that, recognize that standalone positioning and correction-based high-precision positioning serve different roles; GNSS can be used across many processes from site assessment to control point management, staking, and as-built verification; and that accuracy is affected by sky visibility, reflections, communication environment, and work procedures. In wide, multi-process sites like solar power plants, properly understanding GNSS and using different methods as appropriate leads to both efficiency and quality assurance.

In practice, it is more important to be clear about which process you will use GNSS for and why than merely owning equipment. The accuracy needed for site reconnaissance and the accuracy needed for construction staking are not the same. Control point setup and daily point acquisition cannot be handled in the same way. Therefore, after understanding differences in positioning methods, variability due to site conditions, and the need for verification procedures, organize how GNSS will be used for each process. GNSS can greatly improve efficiency in solar power plant surveying, but to realize its benefits you must consider operational design as well.

Going forward, solar power plant sites will increasingly require managing larger areas with fewer personnel and detecting design–construction discrepancies early. How to incorporate GNSS into daily site operations will become an important theme. If you want to more easily bring high-precision position checks to site, it is useful to know options such as LRTK (iPhone-mounted GNSS high-precision positioning device). After mastering GNSS basics, consider solutions that fit your company’s site scale and operational system so you can more readily achieve both accuracy and efficiency in solar power plant surveying.