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UAV Data Fields Explained

Many UAV data fields you see in the web interface should be self-explanatory, but some are not. Here is an overview of some terms you may not be familiar with.

Note that not all fields are always set or available.

UAV Registration

The unique registration number assigned to a UAV by the national aviation authority. In the United States, for example, this is typically issued by the FAA and must be displayed on the UAV. Remote ID messages may include this number to identify the drone operator.

UAV Traffic Management ID

A unique identifier used within the UAV Traffic Management (UTM) ecosystem to track UAV operations. This ID can be assigned by UTM service providers and may differ from the registration number. It enables coordination with airspace services and other airspace users.

UAV Session ID

A temporary identifier used during an active UAV flight session. Unlike the registration or UTM ID, the session ID changes between flights and provides a level of anonymity while still allowing tracking within the scope of the current operation.

Operator License ID

The license or certification number assigned to the remote pilot or operator. This is often issued by a national aviation authority and demonstrates that the operator is authorized to fly the UAV under specific regulations.

Altitude Types

Different systems report altitude using different reference points. When tracking a UAV, it’s important to know what kind of altitude you're seeing so you can properly estimate the drone's actual height in the air.

AGL: Above Ground Level

Interpretation:
Altitude relative to the terrain directly beneath the drone.

How to use:
If it says “120 meters AGL,” the drone is 120 meters above the ground right below it — no further calculation needed.

Why it matters:
Gives immediate insight into obstacle clearance and proximity to people or buildings.

ATL: Above Takeoff Location

Interpretation:
Altitude relative to the drone’s takeoff point.

How to use:
Add the elevation of the takeoff location (from a map or known value) to estimate the drone’s geodetic altitude.

Example: Takeoff elevation = 200m. ATL = 100m → Approx. GA = 300m.

Why it matters:
Helps understand climb/descent behavior, especially when takeoff isn't at ground level.

PA: Pressure Altitude

Interpretation:
Altitude derived from air pressure, standardized to sea level (1013.25 hPa). Independent of terrain or takeoff location.

How to use:
Requires local weather pressure data to convert to true altitude. Not suitable for estimating height above ground on its own.

Why it matters:
Used in aviation to maintain separation from other aircraft.

GA: Geodetic Altitude — Expanded Explanation

Definition:
Geodetic Altitude (GA) is the UAV’s height above mean sea level (MSL), calculated using a mathematical model of the Earth (typically WGS-84). It is the altitude value reported by most GPS receivers.

How it works:

  • GPS satellites provide the drone with its 3D position.
  • GA is the vertical component of that position.
  • It does not account for local terrain, so a drone hovering 100 meters over a valley floor and one hovering 100
  • meters over a mountaintop might both report the same GA, depending on the elevation of the ground beneath them.

How to Interpret GA in Practice

GA by itself doesn’t tell you how high the drone is above the ground unless you also know the elevation of the terrain underneath it.

To derive AGL (Above Ground Level) from GA:

AGL ≈ GA − Ground Elevation

Example:

  • GA = 520 meters
  • Ground Elevation = 450 meters
  • AGL = 70 meters

Why GA Is Useful

  • Map and geospatial alignment: Because it’s tied to a global reference, GA makes it easy to plot drone position and altitude on standard maps.
  • Cross-system compatibility: Remote ID messages, aviation tracking systems, and mapping APIs (e.g., Google Maps, Mapbox, Cesium) all use geodetic coordinates with GA.
  • Situational awareness: Combined with terrain data, GA can give you real-world drone height and improve low-altitude deconfliction awareness.

Caution When Using GA

  • If you don’t subtract terrain elevation, you might wrongly assume a drone is much higher (or lower) than it really is.
  • Accuracy depends on the GPS chipset and correction data (e.g., WAAS or RTK improves this significantly).
  • In hilly or mountainous areas, always reference GA against local terrain elevation to get a meaningful AGL.