December 2011 Edition - The Year In Review
Focus: Tackling Satellite Interference
by Martin Coleman, Executive Director, sIRG with David Hartshorn, Secretary General, Global VSAT Forum and Ralph Brooker, President, SatProf
Satellite interference is a huge problem in this industry and affects a whole plethora of different users across various sectors of this extremely diversified business. The military is no exception and is the one area where fixing the problem of satellite interference is the most crucial, as it can, and often does, jeopardize vital operations.
The problem of interference is widespread and it stems from the phenomenal amount of media and data streaming up to satellites. With so many satellites orbiting our planet, (and more to come!) the first thing that a user, or a system, must do is point it at the right one. With orbital spacing as close as 1.5 degrees, mistakes are often made using flyaway or mobile terminals. As important is the frequency at which the user transmits to the satellite; this has to be correct. In addition, the power at which the signal is transmitted is often forgotten, yet an important factor: Too low and its too weak, too high and it often shows up on small antenna systems as adjacent satellite interference. This delicate setup, as a consequence, is therefore, inherently prone to human and equipment error.
The effect of interference is naturally a loss or degradation of signal, which in a military environment means a potential loss of communications, something, which everyone working in that environment is keen to avoid.
There are a whole range of different causes of interference. A number of years ago we believed the biggest cause to be deliberate signal jamming, however we now know that is not the case and in fact the deliberate sabotage of satellite signals is a very small percentage of the problem, and currently, that is not our highest priority.
Indeed, we as an industry are the main cause, with poor installations and consequently equipment failure, as well as human error. We have found that auto-deploy systems, in particular, exacerbate the situation as unmanned systems are ideal, if not paramount, for communications in hostile environments, which therefore cannot apply the human thought process should something not be quite right. They are used throughout the satellite industry, but one of the most prolific users of these systems is the military. It stands to reason they are extremely useful and have become relied upon, heavily, to reduce both costs and manpower. It would simply not be practical to get rid of them, and that is certainly not what Im suggesting. There are a number of well-thought out, intelligent systems available from very few companies that ensure proper operation at all times. If we could only guarantee that intelligent systems such as these are used, I am confident that alone would significantly reduce occurrences of interference.
Following a lively discussion at our recent sIRG conference, we have just set up a working group to look more deeply into improving auto-deploy software systems, and ensuring they can be as interference-free as possible. The group is just in its first stage and is initially tackling the issue of Satellite Identification. Our hope is to work towards some key resolutions and ideas that we can help introduce into GVFs Product Quality Assurance Framework which they have already begun by working with auto-deploy manufacturers to get those necessary design improvements as standard. We welcome anyone who thinks they may have something to add to this group.
Another common misconception is that interference is something we simply have to put up with. There are, however, a number of ways to reduce interference and I would like to think that we will eventually be able to eradicate it altogether. The only way we can achieve this is by working together. We have already done a lot of work with satellite operators, broadcasters and equipment manufacturers across the globe, establishing a number of initiatives and good working practices to tackle this growing problem. I would like to now engage with the military, as I believe that if we roll-out these same initiatives, we would see a significant reduction in instances of interference within the military arena.
That said, some in the military have done much in trying to prevent interference. For example, the US Navy funded an IRG-GVF side-by-side WiMAX-VSAT C-band test and helped prevent the wireless industry from securing a global identification of C-band. Also, the DoD unit that sets up communications for the President have obtained GVF Certification and imbedded an Examiner on their staff. And there are many more...
Carrier Identification (ID)
Carrier ID has been a major initiative for sIRG thus far in the world of broadcasting, and, in fact, we are currently working closely with satellite operators, broadcasters, and equipment manufacturers to have the NIT Carrier ID in place in time for the 2012 Olympics.
Carrier ID essentially means that the carrier can be quickly identified, so when interference occurs the satellite operator can identify instantly who is causing the problem. With two technologies available, the original ID concept for video transmissions using the Network Information Table (NIT) of the DVB stream and, a newly developed method where the Carrier ID information is contained in a separate carrier that is visible to satellite operators under all interference conditions, without the need to interrupt the main feed. This second method can be utilized on all types of SCPC carrier, whether video or data. This, along with other industry input, is being reviewed by the DVB with a view to producing a Carrier ID standard for all MPEG streams. sIRG is currently working with a number of satellite operators to work towards Carrier ID being mandatory for all of their customers. This was kicked off with an announcement from Eutelsat at IBC 2011 that Carrier Identification, using the NIT method, will be integrated into transmission parameters for all SNG transmissions and new DVB broadcasts from 30 June 2012. It is hoped to extend this in the first instance to other operators and then with the DVB, and move to a situation whereby Carrier ID is mandatory on all transmissions on all satellites.
Of course, Carrier ID is only being applied to the commercial broadcast scenario! I believe, by utilizing very simple ID codes, that military transmissions should be included. After all do we not want the situation where all broadcast carriers in the future have ID and, therefore, by simple analysis, anything else not having an ID must be military?
It is in the interests of everyone in the industry to integrate Carrier ID, however, as it means that if someone else causes interference on your feed, the operator can quickly and efficiently solve the problem, thus you can get on with the job in hand. There are already a number of equipment manufacturers developing and integrating Carrier ID and I would be happy to guide people in the right direction if further information is required.
Training, Installation and Best Practices
A lack of trained installers and bad installations has been a big factor in the instances of interference. The Global VSAT Forum (GVF) has established a system of training and certification for VSAT satellite installers globally. The GVF VSAT Installation & Maintenance Training Course was created to serve as the global industry standard for installers of bi-directional satellite Earth stations. It was established by a consensus of expert volunteers serving in the GVF Education & Training Working Group.
The course was developed and is hosted by GVFs training partner SatProf, Inc. The course uses animation and simulator-based interactivity to highlight and make learning easier. Technicians who successfully complete the training course are automatically added to the GVF Certified Installer Database.
GVF are now looking to integrate these methods for SNG and FlyAway operations.
Our global aim is to only use installers who have undergone formal training and certification to work in all areas of satellite transmission.
Unintended interference can cause serious service disruptions, capacity reduction, and mission compromise. Field technicians and network operations center staff have critical roles in the prevention of interference. To prevent interference, these personnel must be trained not only in installing specific hardware but in several critical, fundamental skills:
1. Accurate antenna pointing
2. Accurate polarization adjustment
3. Proper transmit power adjustment
4. Correct modem signal settings
5. Correct selection of cable and attachment of connectors
In addition, working with the Radio Frequency Interference - End User Initiatives (RFI-EUI) group of broadcasters and other affiliates, the Best Practices and Documentation group is currently updating the Universal Access Procedures (UAP) to catch up with todays technology as well as getting better standards in all parts of our industry.
Product Quality Assurance
Again, our colleagues in GVF have been working hard to bring back order in to our industry by tackling the need for better equipment performance and quality through an industry-approvals framework. GVF, sIRG and RFI-EUI have been working closely with numerous satellite operators and equipment manufacturers to affect this initiative. I know that many manufacturers ensure a great deal of due diligence when it comes to ensuring their products include high quality and outstanding specifications needed for satellite equipment. sIRG has been working with GVF to help define those minimum requirements and introduce a cost effective system of Type Approvals.
As with training, I would like to see a situation whereby equipment not meeting those requirements will simply not get purchased.
Satellite Identification (ID)
Satellite ID, i.e. recognizing a satellite correctly, is considerably more complicated to achieve than Carrier ID and it is something we simply cannot do as yet, but it is something we are working to achieve. The first step towards this is our new working group I mentioned earlier. The first task of that group is to look at Satellite ID and the numerous methods of achieving the identification of any Satellite accurately and simply. This should lead naturally to the improvement of Auto-Deploy and Comms-On-The-Move (COTM) systems specifically and thus, formulating new standards.
Military and Private-Sector Collaboration
The problem of interference is not going to be solved overnight and nor by any one individual or group of individuals. We place a lot of emphasis on working together with the other groups, from within the entire industry, from equipment manufacturers, through to satellite operators, uplinkers to end users; whether that is broadcasters, military users or from the maritime industry, all have an important part to play.
These initiatives are in place to help tackle interference, and we are working to encourage people experiencing interference to share the problem and resolution, or the lack of resolution, ask for guidance and help from our members and associates. Working together in this way, we can solve interference!
Please engage with us...
Return To Top
Return To Top