How do you solve a problem like Galileo? With a strap-on L-band payload, of course!

Rejoice, Brexit Galileo worriers! Your hand-wringing is at an end thanks to research by Brighton-based Professor Chris Chatwin and Dr Lasisi S Lawal of Nigeria's Obasanjo Space Center. Kind of.

How we got here

Depending on your take on the situation, Blighty was either booted out of, or walked away from, the EU's satellite navigation programme, Galileo, following the UK's vote to leave the European Union.

The UK has poured considerable amounts of cash into Galileo, which will give members of the EU their own satellite navigation system rather than rely on the deals made with US for access to its GPS constellation. Once complete, the British military and other UK agencies were looking forward to making use of the accurate and secure Public Regulated Service (PRS).

Whoops! Brit lawmakers were either unable or unwilling to look at the Galileo agreement, which is pretty clear that if you aren't in the EU club, you can't use the equipment.

You can catch up on the whole story from hearing to hearing, with the same questions being asked and the same answers being given to disbelieving lawmakers over and over again. We'll wait.

Back in August 2018, the UK treasury greenlit the spanking of £92m on studying how Blighty might make its own Brexit Satellite (BS) constellation. Earlier, in June 2018, the then UK Defence Procurement Minister, Guto Bebb, put a price tag on the project, estimating it at between £3bn and £5bn. We'd bet it'll be nearer the latter than the former. It's only a matter of time before Chris Grayling is put in charge, after all.

While Chatwin and Lawal's paper won't solve the problem of the UK satellite industry finding its snout lifted from the EU's cash trough, it does attempt to address concerns that the loss of access to the PRS could lead to lower accuracy with an augmentation system bolted to handy geostationary satellites.

Pass the EGNOS

In a chat with The Register, one of the paper's authors, Professor Chris Chatwin, reckoned positioning accuracy down to five centimetres could be achieved very inexpensively by strapping an L-Band navigation rig to a geostationary sat. He told us that "one satellite should cover a third of the world" and "three would do the whole globe".

The theory is that the additional signal would work as an overlay for the existing Galileo or GPS open navigation signals and, via some slightly more specialised equipment on the ground to combine the two, give the UK the accuracy it wants, if not the lucrative contracts the satellite industry craves.

And the cost? Chatwin reckons £100m for the augmentation payload per satellite and about a year to put the thing together. Of course, one has to find a handy bird going to the necessary orbital location on which one could bolt an L-Band navigation antenna and deal with the ground infrastructure. But with three augmentation rigs coming in at £300m, it's a far cry from the billions being bandied around for the BS.

Chatwin and Lawal have form in the augmentation department, having presented papers on Nigeria's NIGCOMSAT-1R, which was launched in 2011 as a replacement for the short-lived NIGCOMSAT-1. The satellite features an L-Band antenna although as of 2015, the Nigerian military had yet to make much (or any) use of the increased accuracy.

The theory is, however, sound. It is also, as the pair acknowledges, quite similar to the European Geostationary Navigation Overlay Service (EGNOS) system. EGNOS was designed to augment the US GPS system and was a precursor to Galileo. A joint project between the European Space Agency (ESA), the European Commission (EC) and Eurocontrol, signals from three dedicated satellites combined with GPS allowed users to determine their location to within 1.5 metres.

The UK Navigation Overlay Service (UKNOS) payload should do a good deal better than that, for less cash and without the need for dedicated spacecraft, according to the paper.

Further savings could be achieved by coming to an arrangement with the operators of NIGCOMSAT-1R to avoid the requirement for additional satellites for redundancy. Such a move, the paper reckons, would "signal to the rest of the world that the UK has become a more outward looking economy."

Or maybe a deal could be done? (stop us if you've heard this one before)

We spoke to space policy expert, Dr Bleddyn Bowen, about the proposal. After a short look at the paper, Bowen questioned the need for such a system, highlighting the similarity to EGNOS, before reminding us that "Britain will still have access to GPS military signals. That is something that hasn’t changed. GPS was always going to be the primary GNSS service for UK MoD and security agency need."

Bowen, who coined the acronym BS (Brexit Satellite), also returned to the theme of the UK and EU coming to an arrangement over the use of Galileo rather than the current posturing of lawmakers, saying "The EU has said it is open to negotiate UK access to PRS signals for the MoD and UK security agencies/civil infrastructure purposes, on the same basis that it is doing for USA and Norway."

So the BS and even the far more modest UKNOS would not be required.

For his part, Chatwin told us he felt the cash being expended on the system "could be better spent elsewhere", before concluding "We don't really need to do this at all."

However, if national pride dictates that the UK has to send something into space in response to becoming a Galileo third country, then at around £100m a pop, the UKNOS augmentation is better value than the billions to be spent propping up the UK space sector on a constellation of Brexit Satellites.

But since when has logic featured in the arguments over Galileo? ®