GNSS Positioning Modes for Land Surveys
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Questions and Answers

Which GNSS positioning mode is characterized by real-time data collection and feedback?

  • Real-Time Kinematic (RTK) (correct)
  • Static
  • Differential GPS (DGPS)
  • Post-Processed Kinematic (PPK)

    • What is the primary characteristic of Static positioning mode?

  • Use of only one reference station
  • Movement of the receiver during data collection
  • Data is processed after collection (correct)
  • Continuous monitoring of satellite signals

    • Which of the following is NOT a GNSS positioning mode discussed?

  • Continuous GPS (CGPS) (correct)
  • Real-Time Kinematic (RTK)
  • Static
  • Post-Processed Kinematic (PPK)

    • In which GNSS mode do data corrections occur after the data is collected?

    <p>Post-Processed Kinematic (PPK)</p> Signup and view all the answers

    What does 'PPK' stand for in GNSS positioning modes?

    <p>Post-Processed Kinematic</p> Signup and view all the answers

    What is the primary characteristic of point positioning in GNSS?

    <p>It determines the user's position through multiple satellite signals.</p> Signup and view all the answers

    Which of the following positioning techniques is NOT utilized in relative GNSS positioning?

    <p>PPK</p> Signup and view all the answers

    What is a key characteristic of kinematic GNSS surveying compared to stop and go surveying?

    <p>It generally provides lower positional accuracy.</p> Signup and view all the answers

    The observation time for a static GNSS survey can vary based on which factors?

    <p>Baseline length, satellite visibility, and satellite geometry.</p> Signup and view all the answers

    In RTK GNSS surveying, what role does the base receiver play?

    <p>It remains stationary and communicates with the rover.</p> Signup and view all the answers

    What is a requirement for a rover receiver during kinematic GNSS surveying?

    <p>It cannot stop while moving over unknown points.</p> Signup and view all the answers

    In relative GNSS positioning, which statement accurately describes the role of the two receivers?

    <p>One receiver has a known position while the other has an unknown position.</p> Signup and view all the answers

    Which of the following modes of GNSS positioning is specifically designed for high accuracy applications?

    <p>Relative positioning using two receivers.</p> Signup and view all the answers

    What processing is required in kinematic GNSS surveying to determine the coordinates of unknown points?

    <p>Post processing must be performed.</p> Signup and view all the answers

    Which statement accurately reflects a limitation of kinematic GNSS surveying?

    <p>It can track multiple satellites but lacks positional accuracy.</p> Signup and view all the answers

    What is the primary purpose of converting raw GNSS data into the RINEX format?

    <p>To standardize data for compatibility and processing</p> Signup and view all the answers

    Which of the following files is NOT typically required in the post processing of GNSS data?

    <p>Image data file</p> Signup and view all the answers

    How does baseline processing contribute to GNSS surveying?

    <p>It computes baseline length and orientation</p> Signup and view all the answers

    During fast static GNSS surveying, what is the key operational characteristic?

    <p>Employing multiple receivers tracking the same satellites</p> Signup and view all the answers

    What additional data file can be used to improve the accuracy of GNSS measurements by accounting for atmospheric conditions?

    <p>Meteorological data file</p> Signup and view all the answers

    Study Notes

    GNSS Positioning Modes

    • GNSS positioning methods include static, rapid static, stop-and-go, kinematic, RTK, and real-time DGNSS
    • These methods differ in the way they are employed and the accuracy they provide

    GNSS Positioning Modes for Land Surveys

    • Guidelines and specifications for land surveys are governed by DAO 2007-29
    • Control Survey Accuracy Specifications are based on DMC 2010-13
    • LMC No. 2015-01 establishes guidelines for RTK GNSS in lot surveys demanding tertiary accuracy

    Two Ways of GNSS Positioning

    • Point Positioning:
      • This method uses a single receiver to calculate the user's position.
      • It provides relatively low accuracy
      • Common in handheld GNSS receivers and mobile phones
    • Relative Positioning:
      • This method employs two or more receivers simultaneously tracking the same satellites.
      • It provides higher accuracy
      • Used for applications such as surveying, mapping, and precise navigation
      • Techniques include DGNSS and RTK.

    Static GNSS Surveying

    • The observation time varies from 20 minutes to several hours, depending on the baseline length and the number of visible satellites.
    • Measurements are typically taken every 10, 15, or 20 seconds.
    • Instrument height must be recorded
    • Post-processing of GNSS raw data is necessary for applying differential corrections and precise positioning calculations
    • Raw GNSS files often need conversion to the RINEX format for further processing.

    Fast (Rapid) Static GNSS Surveying

    • The base receiver remains stationary throughout the observation session.
    • The rover receiver remains stationary for a short interval, then moves to another point for recording.

    Stop-and-Go GNSS Surveying

    • Two or more receivers are used.
    • A base receiver remains stationary.
    • Rover receivers move between unknown points, pausing at each to collect data.

    Kinematic GNSS Surveying

    • Receivers continuously track satellites without stopping at each point.
    • The base receiver remains stationary over the known point.
    • The rover receiver moves over the unknown points without stopping.
    • Requires post processing to calculate coordinates of unknown points.

    RTK GNSS Surveying

    • Similar to kinematic surveying, but it uses a higher data rate (at least 1Hz).
    • Base receiver measurements and coordinates are transmitted to the rover receiver via a radio link for real-time position calculations.
    • Best for large numbers of unknown points in close vicinity to a known point.
    • Allows for precise, real time positioning in the order of centimeters.

    PPK Surveying

    • Used for mapping and surveying requiring centimeter accuracy.
    • Data is collected using two receivers; one is a fixed base station; and one or more rovers.
    • Post-processing of the data is required.
    • Two types: Topo Point Surveys and Continuous Survey.

    Real-Time DGNSS

    • A code based relative positioning method employing two or more receivers to track the same satellites in real time.
    • Ideal when a near submeter positioning is required within few hundred kilometers.

    Control Point Establishment Using GNSS Method in the Philippines

    • Specifications and procedures for CP establishment are governed by DAO 2007-29 and DMC 2010-13
    • These rules address accuracy specifications for various control survey orders.

    Control Survey Accuracy Specifications

    • Geodetic control surveys have different orders of accuracy (first, second, third, and fourth) varying with relative error, linear error, and vertical accuracy dependent on the survey area.

    LMC No. 2015-01

    • Provides guidelines on using RTK GNSS for all lot surveys with tertiary accuracy.

    Section 1: Registration of Receivers

    • RTK GNSS receivers must be registered before use.

    Section 2: Procedures and Conditions for the Use of RTK GNSS

    • Only Dual Frequency receivers are permissible.
    • Use one GNSS receiver as a base station along with at least one rover receiver.
    • Ensure the base station has an unobstructed 15-degree horizon clearance.
    • The Rover receivers are mounted on range poles supported by bipods.
    • All survey areas must have a horizon clearance of at least 15 degrees at all corners.
    • ETS is used to supplement the RTK in situations where the 15-degree horizon clearance isn't met.

    Other Important Guidelines

    • Root Mean Square during RTK GNSS observation should be 35 or lower.
    • RTK observation time for each lot corner shouldn't be less than 2 minutes.
    • Ensure at least 5 satellites are tracked with good geometry (good DOP value).
    • RTK Rover receiver must be initialized before data collection.
    • Minimum baseline length of 200 meters but maximum of 1 Km is recommended.
    • Distance between RTK observation should be compared to ETS distance.

    Annex XX

    • Provides a template for GNSS field sheets (GPS Station Field Sheet)

    Section 24:

    • Contains guidelines to determine GNSS observation time (duration) for Static and Rapid Static surveys relative to different types of receivers and baseline lengths.

    DMC 2010-13 Provisions

    • Covers various aspects, from control point establishment to data processing procedures to ensure the accuracy and reliability of GNSS surveys in the Philippines.
    • Provides detailed instructions on aspects such as survey area geometry, station visibility, instrument setup, observation period, and more for precise measurements.

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    GE-109 Satellite Geodesy Topic 7 PDF

    Description

    Explore the various GNSS positioning methods used in land surveys, such as static, rapid static, kinematic, and RTK techniques. Understand the accuracy specifications and guidelines set by DAO 2007-29 and other regulations. This quiz will help you grasp the key concepts and applications of GNSS in surveying.

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