SatSig topic:

Comparison of three tracking methods-Program Tracking, TLE Tracking, and Vector Tracking

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May 28^th, 2025 at 2:26am

In satellite communications, Program Tracking, TLE Tracking, and Vector Tracking are three distinct tracking methods, each with different principles and application scenarios. Although they are all used to control ground station antennas to point toward satellites, their implementation methods and accuracy levels differ significantly. With the development of satellite communication industry, TLE Tracking, and Vector Tracking are becoming more and more widely used due to their own advantages.

1. Program Tracking

Program Tracking is a method based on pre-programmed satellite orbital data. The ground station calculates the satellite's position in advance using known orbital parameters (such as Keplerian elements or TLE data) and generates a schedule of azimuth and elevation angles over time. The ground station then adjusts the antenna pointing according to this schedule.

2. TLE Tracking

Two-Line Element (TLE) tracking is a widely used method for predicting the position and velocity of Earth-orbiting satellites. TLE data is provided by organizations like NORAD (North American Aerospace Defense Command) and is used in satellite communication systems to determine the location of satellites for tracking, communication, and data transmission purposes.

A TLE is a data format used to convey the orbital elements of an Earth-orbiting object, such as a satellite. It consists of two lines of 69 characters each, containing information about the satellite's orbit. These elements are used in conjunction with an orbital prediction model (such as SGP4/SDP4) to calculate the satellite's position and velocity at a given time.

3. Vector Tracking

Vector tracking is an advanced signal processing technique used in satellite communication systems, particularly in Global Navigation Satellite Systems (GNSS) receivers. Unlike traditional scalar tracking, which processes each satellite signal independently, vector tracking employs a unified approach to estimate the user's position, velocity, and time (PVT) by jointly processing all available satellite signals. This method offers several advantages, including improved robustness, accuracy, and performance in challenging environments.

4. Comparison of the Three Tracking Methods

Jun 3^rd, 2025 at 11:07am

Here are some details about "Step track" system:

Step track

In this tracking system, once the satellite beacon has been initially found manually, the tracking system measures the beacon level and applies periodic step movements to the antenna in azimuth and elevation.

In a step track system, if the beacon level has reduced, the controller might move the antenna experimentally one step. If there is an improvement it carries on till the level starts to decrease. It is possible to then move the antenna to the optimum position.

This process may be repeated on the other axis (azimuth or elevation) as required.

Intelligent step track

To reduce the number of step movements and improve accuracy, software may be implemented to learn the daily orbital movement pattern during the initial 24 hours, and subsequently make step movements in a predictive fashion without waiting for detection of reduced level. The software may also include features to deal with rain fades and thruster firings.

Step track systems need careful set up with consideration given to the antenna beamwith, the angular step movements and motor run times for each step. Read the instructions carefully.

Advantage / Disadvantages

Ideal for slow moving geostationary satellites.

Not suitable for fast moving satellites.

It cannot do an initial finding of the satellite unless aimed approximately manually.

Jun 3^rd, 2025 at 7:37pm

Monopulse tracking

This tracking system requires a special feed system on the antenna with multiple outputs, arranged so that the phase angle difference between the beacon signal appearing at the various outlets relates to the angle that the satellite is off from the central main beam direction.

Advantage and disadvantages
Fast and immediate closed loop following of the satellite.
Good for fast moving satellites.
Good for mobile satellite operation, such as maritime, aircraft or land vehicles.
Requires multiple receivers.

May 5^th, 2026 at 2:05pm

You can read more about Two Line Elements (TLE) and how I work out where are the satellites around the geo orbit.

Deriving geostationary orbit position from 2 line elements using spreadsheet

List of satellites in geistationary orbit

TLE Archive: Old two line elements text files for Geostationary satellites

Coments on the calculation method welcome.