Signal interference has become a problem for all satellite operators and users; however, the provisions of Liability Convention of 1972 on interference with satellites may not be tenable if the “damage” is not caused by another space object.
After fifty years of human reliance on space-based capabilities and applications, a growing awareness of the risk of collisions in space and of vulnerability of space systems to threats posed by space debris in particular and to a lesser extent by space weather has begun. In addition, a further threat is the risk of interference in its various forms. This risk, by comparison, has received relatively little attention so far. While the pre-launch and launch phases are covered by insurance premiums, satellite interference are rarely, if at all covered by insurance claims. In most instances, space insurance was restricted to one phase only. The Intelsat 708 satellite destroyed in a Long March 3B crash on February 15, 1996 offers a case in point. Though the Intelsat satellite 708 was insured for $204.7 million, Intelsat Corporation obtained space insurance for the launch phase only. The launch phase extended from intentional ignition of the rocket to separation of the satellite from the rocket.
In the case of damage, the usual point of reference for compensation in relation to damage caused by launches and satellites are the provisions of the Liability Convention of 1972 but in some, if not most, instances of interference with satellites, the provisions of that Convention may not be engaged if the “damage” is not caused by another space object. The satellite operator and its customers are the victims. In such circumstances the rules providing for legal liability are obscure and likely to be largely ineffective.
However, satellite interference has become a problem all satellite operators and users must contend with at one point or another. With thousands of incidents of interference reported each year and hundreds or even thousands more going unreported, most geostationary satellites will experience some type of interference incident in the duration of their lifetime.
Interference can be categorised into five main groups: interference caused by system users; interference caused by adjacent satellites; interference caused by terrestrial services; deliberate interference; and cross interference caused by misaligned uplink signals in opposite polarised transponders. While approximately 85-90 per cent of incidents are accidental, the net results are the same – a tremendous drain on company resources, including manpower, available satellite capacity and, of course budget. The most common form of defensive interference is ‘jamming’. This can relate to TV and radio transmissions, typically as a means of political censorship of information. Another form would be the jamming of GPS signals for whatever purpose.
Another form of interference includes hacking by persons or by groups such as “Anonymous”, acts of terrorism, acts of commercial sabotage and acts of war. Mostly, this would be aimed at destruction or disruption of services but might extend to taking control of such systems. There is an example of this type of interference with the US reporting that in 2007 and 2008 an unknown power was able access Landsat-7 and Terra EOS AM-1 satellite systems, presumably to test its ability to take control and even destroy such systems. Though not proven, the US authorities voiced suspicions that a foreign power was involved.
It’s not just satellite operators, however, who suffer from these highly unwelcome incidents. Users, who are the ultimate victims, such as TV broadcast networks, transmission equipment operators, even advertisers, have a stake in the integrity of satellite transmission links.
Costly business
The satellite Users Interference Reduction Group (SUIRG) estimates, from member-provided data, that international satellite operators with small-to-large fleets of geostationary satellites positioned in the Atlantic, Pacific and Indian Ocean Regions incurs costs from hundreds of thousands to million of dollars per year due to satellite interference. These losses are two folds. First is the revenue impact from the actual outrage time in some cases. But a significant financial punch can be attributed to the cost of manpower spent locating the source of the interference and mediating a resolution.
From its extensive research on the subject, SUIRG estimates that most large satellite operators lose the equivalent of three quarters to one full ‘person year per satellite’ annually on interference related issues. Most large operators retain personnel dedicated solely to working on identifying and resolving interference issues. The financial strain of interference incidents on satellite operators can run into several million dollars when the loss of capacity and personnel time is added up. As a major US television broadcaster executive puts it, ‘we have spent in excess of US $2.4 million over the past two years resolving interference issues.’
With regard to international regulation, a number of international telecommunications conventions have provisions designed in the allocation of frequencies to avoid causing harmful interference to others but they do not provide effective sanctions for such interference. Certainly, intentional acts of jamming broadcasts to particular States will be contrary to Article 15 of the Radio Regulations, an international treaty governing the use of radio-frequency spectrum and satellite orbits under the supervision of the International Telecommunications Union (ITU), which is an Agency of the United Nations. Furthermore, activities which are conducted to restrict the free flow of information may contravene Article 19 of the Universal Declaration of Human Rights. However, obtaining a remedy is another matter.
As interference is clearly a risk for satellite operators, going beyond business interruption, it is legitimate to wonder about the possibility of insurance against such risk materialising. In fact, under most space insurance policies the risk of electromagnetic and radio frequency interference is specifically excluded. However policies will often cover the risk of physical damage to the satellite directly resulting from such interference and from interference coming directly from the satellite itself.
Battles lying ahead
Two causes of interference that are receiving increased attention come from adjacent satellite and broadband systems. While still accidental, interference caused by adjacent satellite is becoming more prevalent as two degree spacing between satellites in the geostationary arc becomes more common. Since each affected satellite operator is looking to maximise full use of its allocated spectrum, SUIRG is seeing more incidents of ‘stepping on each other’s toes.’ The result lies in better coordination, which also will help reduce disproportional loss of personnel hours.
As more countries look to open the lower portion of the C band for WiMAX, interference potential from terrestrial systems will most likely increase. The WRC-07 ruling created a sound regulatory framework for minimising this potential for interference into FSS; however, left the door open allowing countries to elect if they desired to provide FSS protection. The global map developed by the US Navy, identifies the countries that have elected to allow C-band WiMAX implementations. It is critical that FSS and WiMAX stakeholders adequately implement the WRC-07 decisions to ensure a globally acceptable interference environment in the C-band frequencies.
The WiMAX forum has stated in the white paper that they will not knowingly implement C-band systems within the operational area of an FSS antenna. Consequently it is imperative that transmit plus receive-only FSS antenna latitude and longitude locations be identified in a common database. At the SUIRG 2008 Cairo interference conference, SUIRG took an action to identify where and how to register antenna locations. Without such a database, failure to appropriately register C-band earth stations which operate in frequencies also identified for WiMAX type operations would substantially increase the potential for interference in the C-band.
Stopping interference before it starts may not be possible, but swiftly identifying the root of the problem and resolving the cause with the least amount of drain on the organisation is an attainable goal with the right tools ad industry commitment. The responsibility lies with all operators and users. By sharing information on interference incidents and resolution, ensuring that employees are properly trained, and remaining attentive to the latest regulations, the satellite industry can make tremendous progress in reducing the effect of satellite interference to a more manageable level.
Therefore, the World Radio Communication Conference (WRC 2015) meeting in 2015 will feature discussion on the interference of satellite communications from terrestrial infrastructure and members of the satellite industry are aware they must begin making plans to protect the spectrum they are currently using.
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