🚧 Under construction — VoTechWorks is being built. A free tech program — complimentary, as our commitment to get America working.
voTechWorksGrade 13 · a vocational technology learning center, by urbanicity
newSchoolWorks.com › VoTechWorks › Technology & Design › GIS / Surveying / Drone Operations › GNSS Field Operations and Data Processing › Lesson 12
TEC-GIS45-03 · Lesson 12 · 12 clock hours · lab

Integrated GNSS Survey Project and Report Preparation

Objective. Students will plan, execute, and document a complete GNSS control traverse connecting at least two published control monuments, producing a final deliverable report meeting a simulated client specification.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by an industry-certified professional or by a certification or approval body. It is a study draft and may contain errors. Do not use it as instructions for work on a job site or on live equipment. Always follow your instructor, your supervising professional, and current official references and regulations.

VoTechWorks program approval and accreditation are still in progress. Credentials are issued only by the certifying bodies named in each program, after their own exams.

Integrated GNSS Survey Project and Report Preparation

A GNSS control survey is only as valuable as the documentation that accompanies it. Clients, licensed surveyors, and review agencies cannot verify field work they did not witness; your report is the legal and technical record that stands in for your presence. This lab brings together every skill from the course—benchmark research, field occupation, quality control, and GIS mapping—into one deliverable that mirrors real professional practice.

Phase 1: Planning

Begin by downloading the NGS datasheet for each published control monument you will use. The National Geodetic Survey (NGS) datasheet lists the monument's designation, PID (Permanent Identifier), published horizontal and vertical coordinates, datum, stability rating, and recovery notes. Read the recovery notes carefully; a monument described as "mark not found" in a recent recovery should prompt you to select an alternate. Confirm each monument's published coordinate system and epoch so your final coordinates are consistent.

Next, sketch your survey route on a campus map and calculate approximate baseline lengths between monuments. Identify any locations where overhead obstructions—trees, buildings, power lines—may degrade satellite geometry. A site with a PDOP (Position Dilution of Precision) routinely above 4 should be avoided or rescheduled.

Complete a Job Hazard Analysis (JHA) before fieldwork begins. List every foreseeable hazard: traffic, uneven terrain, electrical infrastructure, heat or cold exposure, and working near active roadways. For each hazard record the control measure: high-visibility vest, traffic control plan, buddy system, sun protection, or other appropriate measure. Your instructor must review and sign the JHA before you leave the building. A JHA with any critical safety omission—such as no traffic control measure noted for a roadside setup—must be corrected before the grade is recorded.

Select your GNSS method. RTK (Real-Time Kinematic) uses a dedicated base receiver set over a known point to broadcast corrections by radio link to your rover. Network RTK (also called VRS or RTN) connects your rover via cellular data to a network of continuously operating reference stations (CORS); no separate base radio is required. Network RTK is efficient for a single-rover crew and avoids baseline-length limitations associated with a single base, provided cellular coverage is adequate at your site. Document your choice and the reason for it in your project description.

Prepare an equipment list that includes each instrument's model, serial number, and most recent calibration or certification date. Calibration records support the report's credibility and are required by many client specifications.

Phase 2: Field Execution

Set up the rover rod at the first monument, centering the bubble and entering the exact antenna height measured to the phase center offset reference point (typically the bottom of the antenna mount or the monument top, per your antenna's calibration sheet). An antenna height error of even a few millimeters propagates directly into your ellipsoid height and, after geoid modeling, your orthometric elevation.

Collect a minimum number of independent observations at each point as required by your method's specifications. For RTK, many state and local standards require a minimum of two independent initializations at each point with a specified number of epochs averaged per initialization. Record the time, solution type (fixed or float), PDOP, number of satellites, RMS, and antenna height for every occupation in your field notebook. A fixed solution means the integer carrier-phase ambiguities have been resolved; a float solution has not resolved ambiguities and carries higher uncertainty—do not accept float solutions for control work.

Perform a redundant observation at each monument: occupy the point a second time after a fresh initialization, or return later in the session. Compare the two coordinate sets. Horizontal and vertical discrepancies within your specification limit (often 2–3 cm for standard control) confirm the observation is reliable. If a redundant observation falls outside tolerance, repeat the occupation and investigate possible causes: multipath, low satellite count, or equipment issues.

Never leave equipment unattended near traffic. Place safety cones or delineators around the setup area consistent with your JHA traffic control plan.

Phase 3: Report Preparation

Back in the lab, process your raw data. For static or long-observation sessions, submit baseline files to NGS OPUS (Online Positioning User Service) to obtain coordinates tied directly to the National Spatial Reference System (NSRS). OPUS returns a solution report showing RMS values, peak-to-peak errors, and the number of reference stations used; include the full OPUS output in your report as an appendix.

For RTK data, export the occupation log from your manufacturer's office software, review the solution statistics, and tabulate final coordinates.

Assemble the report in the following order: cover sheet, project description, equipment list with calibration dates, field occupation log, OPUS or RTK solution outputs, QC summary (redundant observation comparison table), coordinate listing in the required datum and units, and an ArcGIS Pro map showing the survey network—monument locations, baseline lines, and a north arrow, scale bar, and coordinate system label.

The QC summary is where you demonstrate professional rigor. Present a table comparing the two independent coordinate sets at each monument and state whether each passes or fails your tolerance criterion.

Use the provided report template, follow client formatting requirements, and proofread for unit consistency (feet vs. meters, NAD 83 vs. WGS 84 vs. NAVD 88). Submit before the deadline; a score of 75% or higher on the rubric is required to pass.

Safety Reminders

Key terms10

NGS DatasheetAn official National Geodetic Survey document listing a control monument's PID, published coordinates, datum, stability rating, and recovery history.
RTK (Real-Time Kinematic)A GNSS surveying method in which a base receiver over a known point transmits carrier-phase corrections by radio link to a rover, enabling centimeter-level positioning in real time.
Network RTK (RTN)A GNSS correction service that uses a network of continuously operating reference stations and a cellular data link to deliver real-time corrections to a rover without a dedicated base receiver.
Fixed SolutionA GNSS RTK result in which carrier-phase integer ambiguities have been successfully resolved, yielding the highest accuracy and reliability for control surveying.
OPUS (Online Positioning User Service)A free NGS web service that processes static GNSS observation files against CORS network data to produce coordinates tied to the National Spatial Reference System.
PDOP (Position Dilution of Precision)A dimensionless index describing the geometric quality of the satellite configuration overhead; lower values indicate better geometry and smaller positioning uncertainty.
Redundant ObservationA second independent occupation of the same monument, collected after a fresh initialization, used to verify that both sets of coordinates agree within specification tolerances.
Job Hazard Analysis (JHA)A written document that identifies foreseeable hazards for a specific task and records the control measures to be used to protect workers before fieldwork begins.
Antenna HeightThe measured vertical distance from the monument mark to the antenna's phase center reference point, entered into the data collector to correctly reduce observations to the ground point.
QC SummaryThe section of a GNSS survey report that presents a comparison of redundant observations at each monument and states whether the discrepancies are within the specified tolerance.

Worked examples4

1. Your two independent RTK occupations of monument BM-Alpha yield northings of 4,382,145.234 m and 4,382,145.251 m, and eastings of 512,088.467 m and 512,088.459 m. Your project specification requires horizontal agreement within 0.030 m (3 cm). Does this monument pass?
  1. Step 1 – Compute the northing difference: 4,382,145.251 − 4,382,145.234 = 0.017 m.
  2. Step 2 – Compute the easting difference: 512,088.467 − 512,088.459 = 0.008 m.
  3. Step 3 – Compute the horizontal distance between the two solutions using the Pythagorean theorem: √(0.017² + 0.008²) = √(0.000289 + 0.000064) = √0.000353 ≈ 0.019 m.
  4. Step 4 – Compare to the tolerance: 0.019 m < 0.030 m, so the monument passes.
Answer: The horizontal discrepancy of 0.019 m is within the 0.030 m tolerance; the monument passes QC.
2. Your RTK rover's manufacturer datasheet states the antenna phase center offset must be added to the measured slant height. You measure a slant height of 1.842 m from the monument top to the antenna reference mark (ARM). The antenna phase center offset is 0.035 m above the ARM. What antenna height value do you enter into the data collector?
  1. Step 1 – Identify the two components: measured slant height = 1.842 m; phase center offset above ARM = 0.035 m.
  2. Step 2 – Add the offset to the slant height: 1.842 + 0.035 = 1.877 m.
  3. Step 3 – This total is the value to enter as the antenna height in the data collector so the software correctly reduces the observation to the monument mark.
Answer: Enter 1.877 m as the antenna height.
3. You have two NGS-published orthometric elevations for your two monuments: Monument A = 312.456 m NAVD 88 and Monument B = 298.712 m NAVD 88. Your RTK solution gives Monument A an orthometric elevation of 312.471 m and Monument B an elevation of 298.698 m. Compute the closure error at each monument compared to the published values.
  1. Step 1 – Monument A closure: 312.471 − 312.456 = +0.015 m (RTK solution is 15 mm high).
  2. Step 2 – Monument B closure: 298.698 − 298.712 = −0.014 m (RTK solution is 14 mm low).
  3. Step 3 – Record both values in the QC summary table and compare to your specification's vertical tolerance (commonly 2–3 cm for RTK control); both are within a 3 cm tolerance, so both pass.
Answer: Monument A: +0.015 m; Monument B: −0.014 m. Both are within a 0.030 m vertical tolerance and pass QC.
4. You observe monument BM-Delta with RTK and record a PDOP of 5.8 at the time of occupation. Your project specification states PDOP must be 4.0 or less for accepted observations. What should you do?
  1. Step 1 – Recognize that PDOP 5.8 exceeds the specification limit of 4.0; the observation does not meet the quality criterion.
  2. Step 2 – Do not accept this observation for the final coordinate. Note the high PDOP, the time, and the satellite count in the field notebook.
  3. Step 3 – Wait for satellite geometry to improve (PDOP to drop to 4.0 or below) and re-occupy the monument, or return at a time when a mission-planning tool predicts acceptable geometry.
  4. Step 4 – Document the rejected observation and the re-occupation in the field log and QC summary so the reviewer can see the decision-making process.
Answer: Reject the observation, wait for or schedule a time with PDOP ≤ 4.0, and re-occupy the monument; document both occupations in the report.

The math in this lesson2

Learners compute a 0.019 m difference between two GNSS solutions from Northing and Easting with the Pythagorean theorem.
8.G.8N-Q.3
Brush up in the math halls at newSchoolWorks.com:
In class: Planning phase: students research two NGS benchmark datasheets for campus-area monuments, plan a survey route connecting them, complete a JHA, select the appropriate GNSS method (RTK or network RTK), and prepare an equipment list; instructor reviews and approves the plan before fieldwork. · Field execution: students carry out the planned survey, collecting required observations at each control monument and any required intermediate points; each student independently records occupation data and performs a redundant observation at each monument to enable quality checking. · Report preparation: back in the lab, students compile a complete GNSS survey report including cover sheet, project description, equipment list with calibration dates, field occupation log, OPUS or RTK solution outputs, QC summary, coordinate listing, and an ArcGIS Pro map of the survey network; report is submitted for grading.
Materials: Survey-grade GNSS rovers, NGS benchmark datasheets (printed from NGS website), field notebooks, PPE, lab computers with ArcGIS Pro and manufacturer office software, report template, NGS OPUS website
Check: Report is graded against a rubric covering completeness (all required sections present), technical correctness (coordinates and statistics consistent), QC evidence (redundant observations documented), and professional presentation; passing score 75%; any critical safety omission in the JHA section requires revision before the grade is recorded.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

Safety and Compliance
1. Which document must be completed and instructor-approved before students begin field observations in this project?
GNSS Field Operations
2. A GNSS RTK occupation returns a 'float solution' rather than a 'fixed solution.' What is the correct action for control surveying?
GNSS Quality Control
3. What is the primary purpose of collecting a redundant observation at each control monument?
GNSS Field Operations
4. A student measures a slant height of 2.010 m from the monument mark to the antenna reference mark (ARM), and the antenna's phase center is 0.025 m above the ARM. What value should be entered as the antenna height?
GNSS Data Processing
5. Which NGS tool processes static GNSS observation files and returns coordinates tied directly to the National Spatial Reference System?
GNSS Quality Control
6. Two redundant RTK occupations of a monument yield a horizontal discrepancy of 0.042 m. The project specification requires agreement within 0.030 m. What is the correct next step?
GNSS Methods and Equipment
7. Which of the following correctly describes the advantage of Network RTK over single-base RTK for a one-rover field crew?
Survey Control and Research
8. An NGS datasheet for a monument shows a recent recovery note stating 'mark not found.' What is the most appropriate response during project planning?
Record this lesson on my transcript. Sign in with your key and enrollment email to record lessons (enroll free if you have no key). This page stays open to read and practise.
← Previous lessonProgram plan