Big brother in the sky
On 18/05/2011, in Satellite Navigation, by steve
Automatic Dependent Surveillance – Broadcast (ADS-B) is only now starting to make inroads as a surveillance means more accurate and cost-effective than traditional radar. With the ground infrastructure slowly being built, someone has already come up with a new idea: why not put the ADS-B receivers on satellites and start a surveillance service that covers every nook and cranny of the planet, oceans and the deepest mountain valleys included, and sell the service to Air Navigation Service Providers? Whether as a second layer of surveillance or as the primary one, the satellite based solution promises to be much cheaper in deployment and cost of usage than the already not too expensive ground ADS-B network.
This is a very innovative and absolutely market oriented approach that is of course not without some risk. That surveillance data is essential is not in question. Whether ANSPs will be ready to relinquish their hold on the surveillance infrastructure and go for a more efficient and cheaper solution that is as good as or better than the existing heavy iron is the big question of course.
In any case, Iridium thinks the risk is worth taking. These are the same folks whose first attempt at bringing us satellite telephones was a flop but who have risen from the ashes offering more interesting and viable solutions.
Of course the idea is logical and the timing is good. With both Europe and the USA heading towards all aircraft being equipped with ADS-B, broadcasting their GPS derived position and other information for everyone who cares to listen to hear, a system not limited by geography or topography to pick up and forward the broadcast information makes perfect sense, especially if the cost of its deployment and operation is comparable or less than that of a ground based ADS-B network.
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Jamming GPS – No bad guys needed, the FCC will do it for you!
On 16/03/2011, in Satellite Navigation, by steve
Whenever a discussion is started about whether or not we should entrust aircraft navigation to GPS, there will be at least one person raising the issue of jamming. This is the specter of a single bad guy with a little black box purchased on eBay for a few bucks creating havoc in air navigation by jamming the signals of the GPS satellites. As you know, these signals coming from space are extremely weak and the system disengages and stops guidance the moment there is even the slightest doubt about their integrity. Hence the possibility of mischief with just the simplest means.
Losing GPS will not make any aircraft fall immediately from the sky but not having the precision guidance on which the new GNSS procedures rely is akin to having the ILS pulled from under you in Cat III conditions. It is survivable but traffic will be severely handicapped until the service is restored.
It looks now that we will not have to worry about the bad guys. A much bigger threat comes from the US Federal Communications Commission (FCC) and a company called LightSquared. Worse, if LightSquared has its way, scores of other companies rushing to satisfy mobile broadband services might all become potential threats to GPS. So what is the problem?
Companies like LightSquared provide mobile satellite services and there is of course big money in this. In order to increase the capacity of its service, LightSquared is planning to set up a huge number of terrestrial base stations that will operate in the part if the L-band just adjacent to the L1 frequency used by all GPS receivers. These ground stations (effectively a kind of cell-phone operation) transmit at powers that can effectively overload most GPS receivers.
How could something like this come to pass?
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EGNOS Safety of Life Service Available Since Yesterday
On 03/03/2011, in Satellite Navigation, by steve
The European Satellite Services Provider (ESSP) has officially declared the start of the EGNOS Safety-of-Life Service as of March 2nd 2011 following EC authorisation to provide the service.
The EGNOS Safety-of-Life (SoL) Service consists of signals for timing and positioning intended for most transport applications – especially in the domain of aviation- where lives could be endangered if the performance of the navigation system is degraded.
Prior to this date and according to the Single European Sky regulations, ESSP, the EGNOS Service Provider, went through a process of Certification to become an Air Navigation Services Provider and a final acceptance from the French National Supervisory Authority (NSA) had to be achieved.
The EGNOS SoL Service, its coverage area, its expected performances and conditions of use are described in the EGNOS Safety-Of-Life Service Definition Document (SDD).
Once the EGNOS SoL Service has been declared available, Air Navigation Service Providers in the EGNOS service area may proceed with the publication of SBAS precision approach procedures based on EGNOS, once they have established working agreements with ESSP as required by the SES regulation.
In 2003, the airspace users were less than enthusiastic about EGNOS… see here. It will be interesting to see how a decade of changes has affected the community’s perception of this baby…
Troubled Galaxy
On 07/07/2010, in Satellite Navigation, by steve
That space around planet Earth is teeming with man-mad objects is common knowledge and not so long ago we got a good demonstration of what happens when stray metal hits another satellite. For a time it was unclear where a sizeable piece of junk would fall on the surface of the Earth.
The satellites serve a variety of purposes from serving up television to providing internet access and guiding aircraft. It is no exaggeration to say that our modern world would be paralyzed should there be a mass extinction of orbiting satellites. But how robust or fragile is this system in reality?
Galaxy 15 is an Intelsat bird which went out of control in April and has been drifting from its assigned orbital slot ever since. It has threatened to interfere with the functioning of nearby satellites and efforts by ground engineers to disable its payload have initially been unsuccessful.
Does this have an impact on aviation? You bet!
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