--- title: "GPS field procedure and components" subject: "Surveying II" chapter: 8 key: "semester_4/surveying_ii:gps-field-procedure-components" source: https://www.bctengineer.com/q/semester_4/surveying_ii/gps-field-procedure-components site: BCT Engineering --- # GPS field procedure and components Surveying II · Chapter 8: Field Astronomy and GPS - Asked in: 2076 Bhadra, 4 marks - Video: [A Gentle Introduction To GNSS Field Surveying](https://www.youtube.com/watch?v=ymNq9yFotgs) — Redefined Horizons Learning - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_4/surveying_ii/gps-field-procedure-components - Whole chapter: https://www.bctengineer.com/md/semester_4/surveying_ii/chapter-8 ## Question Describe briefly about field procedure of GPS and components of GPS. ## Short answer GPS field procedure: plan with good satellite geometry, select open-sky stations, set up antenna with accurate height, observe for the required session, record field data, and process baselines for network adjustment. GPS components are the space segment (24+ satellites), control segment (tracking and updating stations), and user segment (receivers). ## Answer #### Field procedure of GPS 1. **Planning:** study the area, locate existing control, check satellite visibility and DOP, and plan the observation sessions. 2. **Station selection:** choose points with a clear sky view above 15°, away from reflecting surfaces and electrical interference. 3. **Set-up:** centre and level the antenna on the tripod over the station mark; measure the antenna height. 4. **Observation:** start the receiver, enter the station name and antenna height, set the logging interval and observe for the required session time (a few seconds per point for RTK after initialisation; 30 min or longer for static). 5. **Recording and processing:** note the details in the field book, download the data, process the baselines, adjust the network and convert to the local datum. #### Components of GPS 1. **Space segment:** 24+ satellites at about 20 200 km in six orbital planes, transmitting L1 and L2 signals and the navigation message. 2. **Control segment:** master control station, monitor stations and ground antennas that track the satellites and update orbit and clock data. 3. **User segment:** GPS receivers and antennas used by the surveyor for positioning. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What is the correct order of the GPS field procedure? A. Observation, planning, set-up, station selection, processing B. Set-up, planning, processing, observation C. Processing, planning, observation, set-up D. Planning, station selection, set-up, observation, recording and processing Answer: D. Planning is first, then station selection, set-up, observation, and finally recording and processing. (Key point: Field procedure order) 2. Which condition makes a good GPS station? A. Clear sky view above about 15° elevation, away from reflecting surfaces and power lines B. Close to tall buildings so signals bounce and reach the antenna C. Under tree cover to protect the antenna D. Beside a transmitter tower for a strong signal Answer: A. A clear sky view avoids blocked satellites, and keeping away from reflectors and electrical interference reduces multipath and noise. (Key point: Station selection) 3. Which are the three segments of GPS? A. Satellite, ground and orbit segments B. Space, control and user segments C. Space, transmission and receiver segments D. Master, monitor and user segments only Answer: B. GPS consists of the space segment (satellites), the control segment (master and monitor stations) and the user segment (receivers). (Key point: GPS segments) 4. What does the control segment do? A. Receives signals and computes the user's position B. Carries the L1 and L2 carrier signals C. Tracks satellites, computes orbit and clock corrections and uploads them to the satellites D. Measures the antenna height at the station Answer: C. Master and monitor stations track the satellites, compute ephemeris and clock errors and upload them. (Key point: Control segment role) ## Related in Surveying II - [GPS field procedure](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Agps-field-procedure) — Surveying II, chapter 8 - [Short note: GPS principle and components](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Agps-principle-components) — Surveying II, chapter 8, asked 19× - [GPS, components and working principle](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Agps-components-working-principle) — Surveying II, chapter 8, asked 19× - [GPS principle and components, GIS applications](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Agps-principle-gis-applications) — Surveying II, chapter 8, asked 2× - [GPS principles, components, applications](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Agps-principles-components-applications) — Surveying II, chapter 8 - [Field procedure of aerial photogrammetry, relief displacement](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Aaerial-photogrammetry-field-procedure-relief-displacement) — Surveying II, chapter 7, asked 2× ## Related in other subjects - [Field procedure of chain surveying](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Afield-procedure-chain-survey) — Surveying I, chapter 3, asked 4× - [Field procedure of compass traversing](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Acompass-traverse-field-procedure) — Surveying I, chapter 4 - [Field components from potential V = 15x−3x²y+12yz²](https://www.bctengineer.com/question.md?key=semester_1%2Fengineering_physics%3Apotential-xyz-field-components) — Engineering Physics, chapter 7 - [TE field components; 1 GHz in 5 cm waveguide](https://www.bctengineer.com/question.md?key=semester_7%2Frf_and_microwave_engineering%3Ate10-1ghz-5cm-waveguide) — RF and Microwave Engineering, chapter 4