At Holkirk Communications, we have developed a common interface platform, we call AIM (Antenna Interface Module) across our entire Next Generation Land Terminal range that provides a sophisticated mobile command and control solution that meets these needs, ensuring efficient antenna positioning, multiple satellite location, and inclined orbit tracking across C, X, Ku, and Ka-Band frequencies, for systems from 60cm up to 2.5M in size.

Our auto-acquire and tracking solutions come in multiple deployment scenarios:

• Person-Pack: Ideal for fast setup and immediate use.
• Flyaway Terminal: Portable and easy to transport, perfect for field operations.
• Vehicle Mounted: Provides reliable communication on the pause.
• Deployable Earth Stations: For fast deployable command centres.

Acquiring Inclined Orbit Satellites

Our AIM control unit is engineered to track non-geostationary (non-GEO) satellites, including those in inclined orbits. These inclined orbit satellites can present challenges due to their unique movement patterns, but the AIM control unit is equipped with sophisticated functionalities to address these challenges.

Toast Rack Search Method

One of the key features of the AIM control unit is its ability to perform a toast rack search during the initial acquisition of the satellite. This method utilises the beamwidth of the satellite receive frequency, the current inclination angle of the satellite, and the estimated position (box centre) of  the orbital slot satellite of the designated geostationary position.

By carefully calculating these parameters, the AIM control unit systematically scans the sky, searching for the satellite beacon, and performs various calculations for  side-lobe rejection,  ensuring that the antenna is accurately aligned with the satellite’s current position. This process optimises the acquisition and tracking of inclined orbit satellites, providing reliable communication links.

Video to show the Holkirk SCARAB Person-Pack acquiring SKYNET 4E that has an inclination of 14º with no NORAD TLE data. RESULT – locked and tracking within 3 miniutes

Integration with NORAD TLE Data

In addition to the toast rack search method, the AIM control unit leverages data from NORAD’s Two-Line Element (TLE) sets. This data is sourced directly from NORAD’s extensive satellite catalogue and is continuously updated to ensure precision in satellite tracking.

The AIM controller’s algorithm uses this TLE data, allowing it to predict satellite positions with remarkable accuracy without the need for a toast rack search. This predictive capability of the acquire process saves valuable minutes and is another great tool for maintaining robust and reliable communication links, especially for non-GEO satellites.

Video to show the Holkirk SCARAB Person-Pack acquiring SKYNET 4E that has an inclination of 14º with NORAD TLE data. RESULT – locked and tracking within 2 miniutes

Predictive and memory tracking

Complementing the toast rack and TLE acquire and tracking methords, the 24-hour learning algorithm implemented in the AIM controller further enhances its predictive capabilities.

By continuously analysing and adapting to satellite movement patterns, the algorithm learns and refines its models, offering unparalleled precision in non-geostationary (NON-GEO) satellite tracking. This dual approach ensures that the AIM controller remains versatile and effective, regardless of the satellite’s orbit.

Why Do Satellites Go into an Inclined Orbit?

Satellites are initially placed in geostationary orbits, where they remain fixed relative to a point on the Earth’s surface. However, over time, the gravitational influences of the sun and moon cause these orbits to become inclined. This inclination results in the satellite moving north and south relative to the equator, forming a figure-eight pattern in the sky.

Holkirk AIM Inclined Orbit Tracking Antenna Controller: A Game-Changer

The Holkirk AIM inclined orbit tracking antenna controller is designed to seamlessly track satellites in inclined orbits, ensuring reliable and continuous communication.

Here’s how it stands out:

Search parameter optimisation: As the actual position of the satellite will change with time of day and location of the earth station, our algorithm will calculate the best search window to find the inclined satellite reducing the time taken to locate and increase the reliability.

Satellite path LEARNING: Once the satellite has been located the ACU will perform a TRACK procedure, for the first 10-20 minutes the AIM will instruct initial course PEAKs to determine direction and velocity of satellite. During a 24-hour period the AIM controller will periodically re-peak by jogging the antenna and the AGC signal strength of the beacon receiver monitored. The time and position of the antenna on bore sight are recorded in the AIM memory table which is stored in non-volatile memory. The interval between movements is determined by antenna size, the frequency.

Progressive MEMORY TRACK: After the 24-hour LEARNING phase the antenna control unit will drive the antenna motors to keep the system pointing at bore sight of the satellite irrespective of the beacon being present.
The accuracy of the Memory table is monitored by periodically making very small peaking movements of the antenna and analysing the beacon receiver AGC signal.

User-Friendly Interface: Designed for ease of use, the AIM controller guides users through the acquisition process with intuitive graphics and step-by-step instructions. Also, the controller has a range of unique features including:

• Power outage alarm and indication
• Manual intervention indication
• Activity log files
• Manal JOG
• 30 satellite database

Enhanced Operational Capability: By efficiently managing the tracking of inclined orbit satellites, the AIM controller extends the operational life of military satellites, maximizing the utility of sovereign networks.