What Is Static GNSS Survey? How It Works and When to Use
Static GNSS survey is a positioning method where a receiver remains stationary at a point for an extended observation period — typically 20 minutes to several hours — collecting raw satellite data that is later processed in office software to determine the point's precise coordinates. Static GNSS achieves millimetre to sub-centimetre accuracy (±3–10 mm) — better than RTK — but results are not available in real time. It is the standard method for establishing high-accuracy control networks, geodetic benchmarks, and monitoring points where RTK's real-time capability is not required and maximum accuracy is the priority.
In This Guide
1. What Is Static GNSS Survey?
Static GNSS survey is a differential positioning technique where two or more GNSS receivers simultaneously observe the same satellites from different known and unknown points for an extended period. Unlike RTK — where a rover moves continuously and receives real-time corrections — in static survey, every receiver stays completely still throughout the observation session.
The Key Principle
By recording carrier-phase observations over a long period from multiple receivers simultaneously, the post-processing software can resolve integer ambiguities with much higher reliability than is possible in real-time RTK. More observations, more satellite geometry changes, and more time for the processing algorithms to find the correct integer solution all combine to produce millimetre-level baseline vectors between the occupied points.
What Gets Recorded
Each receiver logs raw GNSS observations — carrier-phase measurements, pseudoranges, satellite ephemerides, and signal quality data — at a defined recording interval (typically 1–15 seconds) throughout the session. These files are saved in RINEX format (Receiver Independent Exchange Format) for processing in office software.
The Result
After post-processing, the coordinates of unknown points are determined relative to known control points with typical accuracy of ±3–10 mm horizontal and ±5–15 mm vertical — better than most RTK results.
2. How Static GNSS Works
Static GNSS Process — 5 Steps
Place Receivers on Known and Unknown Points
At minimum two receivers are required: one on a point of known coordinates (the reference) and one on the point to be determined (the rover). For network surveys, multiple receivers occupy multiple points simultaneously. All receivers must be precisely centred over their marks with correctly measured antenna heights.
Simultaneously Observe the Same Satellites
All receivers collect data at the same time, tracking the same satellites. The observation session length depends on baseline length and required accuracy: 20–30 minutes for baselines under 20 km, 1–4 hours for baselines up to 100 km, and several hours to days for very long baselines or geodetic control establishment.
Log Raw GNSS Data
Each receiver records all carrier-phase and pseudorange observations to its internal memory throughout the session. Data is recorded in the receiver's native format and later converted to RINEX for processing. Recording interval is typically set to 5–30 seconds for standard control surveys.
Download and Prepare Data for Processing
After the field session, RINEX files are downloaded from all receivers. The known reference station coordinates, antenna heights, and observation periods are confirmed and entered into the processing software.
Post-Process in Office Software
Processing software (e.g., Leica Infinity, Trimble Business Center, RTKLIB, or similar) computes the baselines between all occupied points, resolves integer ambiguities, and outputs final coordinates with quality statistics. Results include coordinate values, baseline precision, and variance-covariance matrices for network adjustment.
3. Static GNSS Accuracy: What to Expect
Static GNSS typically achieves better accuracy than RTK because the processing uses far more observations over a longer time window, allowing more reliable integer ambiguity resolution and better statistical averaging of atmospheric errors.
Typical Accuracy Figures
Short baselines (under 20 km), good conditions:
- Horizontal: ±3–5 mm
- Vertical: ±5–10 mm
Medium baselines (20–100 km):
- Horizontal: ±5–10 mm
- Vertical: ±10–20 mm
Long baselines (100+ km) or extended geodetic sessions:
- Horizontal: ±3–10 mm depending on session length and number of reference stations
Factors Affecting Static Accuracy
- Session length: longer = better ambiguity resolution
- Baseline length: shorter = better atmospheric correlation
- Number of satellites: more = better geometry
- Multipath at the antenna: site selection is critical
- Antenna height measurement: errors propagate directly
- Reference station quality: use IGS or national CORS reference stations where possible
Comparison to RTK
RTK in Fixed solution achieves ±8–15 mm under normal conditions. Static GNSS in good conditions achieves ±3–5 mm. For control network establishment, this additional precision justifies the time investment.
4. Static GNSS vs RTK: Full Comparison
Static and RTK are complementary techniques. The table below summarises the key operational differences.
| Parameter | Static GNSS | RTK GNSS |
|---|---|---|
| Results available | After office processing | Instantly in the field |
| Typical horizontal accuracy | ±3–10 mm | ±8–15 mm |
| Observation time per point | 20 min to several hours | 10–30 seconds |
| Operator movement | Stationary — receiver stays fixed | Moving — operator walks to each point |
| Number of receivers needed | Minimum 2 (simultaneous) | 1 rover + correction source |
| Real-time stakeout | Not possible | Yes — primary use case |
| Best for | Control networks, benchmarks, monitoring | Topographic survey, stakeout, mapping |
| Requires office processing | Yes — mandatory | No — optional |
| Works without internet | Yes — logs data for later processing | Needs CORS or local base for corrections |
| Satellite geometry changes | Benefits from geometry change over time | Fixed geometry at moment of observation |
Static and RTK are complementary, not competing. Most professional survey operations use static to establish the control network and RTK to pick up detail and stake out design within that framework.
5. When to Use Static GNSS (and When Not To)
Use Static GNSS When
1. Establishing control networks — When you need a set of precisely coordinated points that other surveys will reference throughout a project. Static GNSS provides the highest-accuracy coordinates for control monuments, benchmarks, and traverse stations.
2. Geodetic and cadastral control — National mapping agencies, universities, and large-scale engineering projects use static GNSS to establish or extend control frameworks tied to the national geodetic datum.
3. Subsidence and deformation monitoring — Mining subsidence, dam settlement, and landslide monitoring require repeated high-accuracy observations at the same points over time. The ±3 mm accuracy of static GNSS detects movements that RTK would miss in the noise.
4. Underground mine survey — Surface GNSS control points established by static survey at mine portals and shaft collars provide the starting coordinates for underground total station traverses.
5. Connecting to national datum — When your project must tie precisely into the national geodetic framework — not just approximate WGS84 — static GNSS sessions processed against national CORS reference stations provide the rigorous datum connection required.
Do Not Use Static GNSS When
You need results in real time, you are staking out design coordinates, or you are doing high-volume topographic pickup. RTK is faster and sufficient for all these tasks.
6. Static GNSS Field Procedure
The field procedure for static GNSS is straightforward but requires strict attention to several details that directly affect accuracy.
- Site selection: Choose points with open sky view above 15° elevation in all directions. Avoid reflective surfaces within 5–10 metres of the antenna — multipath is the largest single source of static GNSS error. For monitoring points, choose stable bedrock or deep concrete foundations.
- Centring and levelling: Set up the tripod and tribrach precisely over the mark using the optical or laser plummet. Centring tolerance should be within 1 mm. Level the tribrach carefully.
- Antenna height measurement: Measure the vertical height from the ground mark to the Antenna Reference Point (ARP) precisely. Measure twice, from both sides. Record to the nearest millimetre. This is the most common source of systematic error in static surveys.
- Start logging: Configure the receiver to log at the appropriate interval (5–30 seconds). Note the start time and confirm data is being recorded.
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Minimum observation times:
- Baselines under 20 km: 20–30 minutes minimum
- Baselines 20–100 km: 1–4 hours
- Baselines over 100 km or geodetic work: 4+ hours
- Do not disturb: Once logging starts, do not move or bump the receiver or tripod. Any movement during the session creates a cycle slip — a discontinuity in the carrier-phase data that degrades or destroys the session's accuracy.
7. Processing Static GNSS Data
Static GNSS data processing transforms raw receiver logs into precise coordinates. The processing workflow:
Step 1 — RINEX Conversion
Download raw data files from all receivers and convert to RINEX format. Most GNSS receivers export RINEX directly or include conversion software. RINEX is the universal exchange format accepted by all processing software.
Step 2 — Baseline Processing
Processing software computes the baseline vector between each pair of simultaneously occupied points. Integer ambiguities are resolved using the long observation window. The software reports baseline length, azimuth, and quality statistics (RMS, ratio test) for each baseline.
Step 3 — Network Adjustment
For surveys with multiple points, a least-squares network adjustment combines all baselines into a consistent solution. Known control points fix the network in the required datum and scale. The adjustment reports final coordinates and their standard deviations.
Free Processing Software
RTKLIB is a widely used open-source toolkit for static GNSS processing. Commercial options include Leica Infinity, Trimble Business Center, and Topcon Magnet Tools. APEKS receivers output standard RINEX files compatible with all processing platforms.
8. FAQ
How long does a static GNSS session need to be?
Minimum observation time depends on baseline length. For baselines under 20 km, 20–30 minutes is typically sufficient for centimetre accuracy. For baselines of 20–100 km, plan 1–4 hours. For geodetic control work or baselines over 100 km, sessions of 4+ hours are standard. Longer sessions improve ambiguity resolution reliability and reduce the effect of atmospheric errors.
Can I do static GNSS with a single receiver?
Not in the traditional sense. Static GNSS requires simultaneous observations from at least two receivers to compute a baseline. However, if a national CORS network archives its continuous observations, you can occupy your unknown point with one receiver and download the CORS reference data for the same time window afterward — effectively using the CORS station as your second receiver without needing to own one.
What is the difference between static and rapid static?
Rapid static (also called fast static) uses the same basic technique as static GNSS but with shorter observation times — typically 5–20 minutes per point. It achieves similar accuracy to standard static for short baselines under 10–15 km by using modern multi-constellation receivers with good satellite geometry. Rapid static is more productive for control surveys where many points must be occupied in a single day.
Can APEKS receivers log raw data for static processing?
Yes. All APEKS professional receivers — including the AP80 Pro, AP40 Laser+, AP10, AP20, and MAX5 — support raw GNSS data logging in RINEX format. The receiver records carrier-phase observations, pseudoranges, and satellite data to internal memory during a static session. Files are downloaded after the session and processed in standard office software. This allows the same APEKS hardware to be used for both real-time RTK survey in the field and static control establishment.
Is static GNSS used for monitoring?
Yes — deformation and subsidence monitoring is one of the most important applications of static GNSS. By re-occupying the same points repeatedly over weeks, months, or years and processing each session against stable reference stations, surveyors can detect ground movement of just a few millimetres. Applications include dam settlement monitoring, mine subsidence detection, landslide early warning, and building structural health monitoring. The ±3–5 mm accuracy of static GNSS is essential for detecting small movements — RTK's ±8–15 mm noise floor would mask the signal.
RTK IN THE FIELD. STATIC IN THE OFFICE. ONE RECEIVER.
All APEKS professional receivers log raw RINEX data for static post-processing and deliver real-time RTK Fixed solutions in the field — on the same 1408-channel hardware. Establish your control network with static, then stake out your design with RTK. No equipment change required.
View APEKS GNSS Receivers →References and Further Reading
- ISO 17123-8:2015 — Field Procedures for GNSS RTK
- RTCM Standard 10403.3 — Differential GNSS Services
- RTKLIB — Open Source GNSS Processing Software
- IGS — International GNSS Service: igs.org
- APEKS AP40 Laser+ Technical Datasheet, 2026
- APEKS MAX5 Base Station Datasheet, 2026
- ApekSurv Field Software User Guide, 2026