Data Measurement and Pace Segment Calculation

Measured Data

• Data points are collected automatically, as part of a larger data set, and are measured at consistent intervals.
• Each data point represents a specific Point of Interest (POI).
• The purpose of collecting this type of data is to analyze patterns and trends.
• Data points are considered independent, meaning they are not reliant on each other for interpretation

Pace Segment Calculation

• The difference between the measured distance and the actual distance is the deviation.
• Deviations are caused by:
  • Random noise:
    • Scintillation: Sudden changes in the refractive index causing signal variations.
    • Multipath: Indirect signals reaching the receiver.
• The distance between the ranging master and the object is calculated as L=c∗(t2−t1)L = c * (t_2-t_1)L=c∗(t2​−t1​) where:
  • ccc is the speed of light
  • t1t_1t1​ and t2t_2t2​ are the start and end times.
• In 3D systems, the distance is calculated as L=sqrt((x2−x1)2+(y2−y1)2+(z2−z1)2)L = sqrt((x_2-x_1)^2 + (y_2-y_1)^2 + (z_2-z_1)^2)L=sqrt((x2​−x1​)2+(y2​−y1​)2+(z2​−z1​)2)

Error Sources

• Internal problems affecting measurements are related to the space segment.
• Some of these issues include:
  • Satellite clock errors
  • Ionospheric and tropospheric delays
• The most common error source is the influence of indirect signals or multipath.
• Receiver noise can also affect accuracy.
• A system that uses satellites and ground stations to provide corrections results in more accurate positioning.

Off Measurement Approaches

• Data can be collected in a few ways:
  • Time-based measurements are taken at regular intervals regardless of changes in location.
  • Location-based measurements are triggered when a significant change in position is detected.
  • Change based measurements are triggered when a specific event occurs at a particular location.
  • Event based measurements happen when activities like phone calls, text messages, or public speaking take place.

Global Navigation Satellite Systems (GNSS)

• These are systems that use a constellation of satellites to provide positioning, timing, and navigation services.
• Currently, the following GNSS systems are operational:
  • GPS (US): With the largest coverage, it's the most commonly used system worldwide.
  • GLONASS (Russia): The smallest in terms of coverage.
  • BeiDou-2 (China): Featuring the widest coverage.
  • Galileo (EU): Covering a smaller area.
• Key components of GNSS systems include:
  • Space segment: Includes the satellites which transmit signals.
  • Control segment: Consists of ground stations that track the satellites and transmit corrections.
  • User segment: Uses receivers to process signals and calculate position.

This quiz tests your understanding of measured data and pace segment calculations in varying contexts. You'll explore concepts such as independence of data points, causes of deviations, and distance calculations using time and coordinates. Prepare to analyze the patterns and trends derived from data collection methods.