TLE Tracking Module Operations
Guide
AvL Technologies
| Proprietary – Content is Subject to Change without Notice
3
1.
Introduction
1.1.
Overview
This module adds the capability for the AAQ to perform TLE (Two Line Element) tracking. If desired, the module can
also be configured to augment the TLE tracking with scans and step tracking to further increase tracking accuracy.
To activate the TLE Module, select a profile which is configured to use the TLE module. Then simply select the
“Acquire” button on the AAQ remote GUI. The antenna will initialize all sensors and obtain antenna positioning data. It
may also refine the terminal heading by using either SatTant or Reference Satellite functions. The tracking module will
then become active and use the configured TLE data to find the satellite and begin tracking.
When step track scanning is enabled, the module will scan for signal power using the configured signal source device
to correct for any errors in heading and refine the satellite location before performing TLE tracking. The module will
also run step track periodically to further refine the satellite location and ensure the antenna is centered on the peak
power location.
1.2.
TLE Track Concepts
A two-line element set (TLE) is a data format encoding a list of orbital elements of an Earth-orbiting object for a given
point in time, the epoch. Using suitable prediction formula, the state (position and velocity) at any point in the past or
future can be estimated to some accuracy. The TLE data representation is specific to the simplified perturbations
models (SGP, SGP4, SDP4, SGP8 and SDP8), so any algorithm using a TLE as a data source must implement one of the
SGP models to correctly compute the state at a time of interest.
The format uses two lines of 80-column ASCII text to store the data. The United States Air Force tracks all detectable
objects in Earth orbit, creating a corresponding TLE for each object, and makes available TLEs for non-classified objects
on the website Space Track. The TLE format is a standard for distribution of an Earth-orbiting object's orbital elements.
TLEs can describe the trajectories only of earth orbiting objects.
Note: TLE data becomes less accurate with age and must be updated regularly.
