ESA sees satellite-based air traffic monitoring on near horizon The European Space Agency (ESA) has awarded a contract to a US company to create a technology demonstrator for a proposed aircraft monitoring system using low Earth orbit satellites. Spire Global, headquartered in San Francisco, won the €16 million ($17.6 million) agreement for the EURIALO project, which aims to prove that a …
As far as I recall, ESA are not supposed to directly award contracts to companies that are not based in one of its member states, particularly for contacts issued under the ARTES programme. Also, I am amazed that a the German government allowed a US company to win the contract when it is being largely funded by Germany - that bulk of that money should have gone to a German company (e.g. ADS GmBH) as prime contractor (they can then sub-contract, but that is a different matter). Seems like there is something else about this story that El Reg may have missed.
@UCAP
ESA is cooperating with the USA since a long time in fields like
Space science
Human spaceflight
Satellite navigation
Meteorology
Earth science/ Earth observation (other than meteorology)
Space exploration.
https://www.esa.int/About_Us/Washington_Office/Cooperation_with_the_United_States
https://en.wikipedia.org/wiki/European_Space_Agency
“Spire said it plans to open an office in Munich, Germany, as part of the contract after recently establishing a subsidiary in the country.”
https://spacenews.com/spire-to-devise-gnss-independent-aircraft-tracking-satellites-for-esa/
That’s how the game works!
ESA is independent of the EU, in fact it pre-dates it by a considerable margin. Brussels has tried a couple of times to take control of ESA (on the basis that it includes the word "European"), but has been firmly told to take a hike.
ESA funding rules are by and large simple to understand - the money a country gets out of an ESA programme is a function of how much money it puts into the programme. Hence the UK gets a lot out of some programmes, but is essentially blocked from bidding for contracts in other programmes (which it does not fund). Also all countries have to contribute something to ESA's general operational costs; I can't remember the formula for that.
"Brussels has tried a couple of times to take control of ESA (on the basis that it includes the word "European")"
That's a hilarious thought process. Made me wonder if they also want to take over Eurovision or if they claim royalties for National Lampoons European Vacation.
There are *several* important European institutions that the Commission has executed a coup, purely because they have the word European in the name.
E.g. The European Patent Office is not an EU institution, it existed before EU and is completely independent. As of June 1 this year, the Unified Patent Office was initiated by the Commission. If you held an existing patent with the European Patent Office, it has been *unilaterally* and by default moved over to the Unified Patent Office! If you failed to object, in the six-week period allowed to do so, which is now over, you no longer hold a European Patent and you can’t go back. There are, by the way, some good reasons to object, as there are important IP rights you lose in allowing it to pass to UPO.
Most of the original EU treaty organisations have been effectively eviscerated - there were nearly dozen outside the Commission. But the roles are now all duplicated and mastered by Commission Directorates. For example, if you were planning a nuclear reactor, you might expect that to be a Euratom role. But, any direct research is now done through the European Commission Joinr Research Centre, indirect out of Commission Horizon, and all the regulation comes out of Commission DG Energy and DG Environment. Same story on European Environment Agency, also a separate EU Agency established under treaty. Commission has eaten *everything*.
.... of accuracy that will be going for. Cos the accuracy will be determined by the accuracy of the clock fitted to the LEO satellite, as well as the accuracy of the satellite location.
This is pretty much GPS in reverse. Instead of one receiver receiving radio signals from multiple transmitters it is multiple receivers receiving transmissions from one transmitter. In both cases the quality of the clock in the satellite element will be a key component to the accuracy of the resulting calculated position.
You will still have the 'normal' GPS issue that Lat & Long will be far more accurate than altitude.
If it were me, I wouldn’t receive the signal independently on the N satellites. I would have each satellite simply upconvert the signal by Nx”a smidge”, amplify and rebroadcast to its neighbours. A master satellite (which can be any of them) then sees all N copies of the signal at the same instant, absolute time becomes irrelevant. Then, no need for a super-high-accuracy atomic clock, because it only needs to calculate time *differences*. The signal can be defined spread spectrum, then as long as the shift is greater than maximum Doppler, there’s no confusion as to which copy was originally received at which satellite. You do still need high-accuracy orbital almanac.
Also: they do need to get the data back down from the constellation, which is difficult because there’s no single ground station that all the satellites are over. Therefore, laser intersatellite links. Not cheap, but it’s a solved problem. Or use EDRS-C on Hylas for backhaul. For the avoidance of doubt, yes that last option was a rather bitter joke.
It is even simpler, you fit the satellite with a GPS-disciplined oscillator and time source, then it has the ability to measure Doppler and time-of-arrival of data to near-atomic master clock levels.
Send summary messages down of that using usual telemetry channels and somewhere else they can all be correlated and triangulated on the basis of the measurements.
Maybe. I remain to be convinced it’s simpler in practice.
The LEO is moving at 7.8kps, so you have to flywheel that GPS info from “when the GPS radio front end received the data” to “where am I now that I have processed the GPS data”. You need an accurate and deterministic latency on both the GPS module and every other element on the datapath, down to sub-nanosecond. Ditto absolute latency on main RF signal receive, that doesn’t drift over temperature and life. And there’s the digits: a standard satellite data bus at 1Mbps tick is going to be laughably inadequate for synchronising that. By the time you’ve spent man years in design, and working out calibration procedures, I reckon you’ll wish you’d picked up an off-shelf transparent amplifier chain, and just pressed the big GO button on manufacture…..
OTOH your solution can definitely be made to work, because it *is* done that way on Synthetic Aperture Radar constellations. But those cost a truck-ton of money. Still reckon my way is cheaper and takes fewer technical risks. Maintaining *absolute* timing like that is always vulnerable to “oh shit I forgot” really late in integration.
Yes, it can be done and is fairly easy (for a given definition of "easy" in hardware design). Depending on SNR it is not too difficult to resolve the timing of a data stream to around 1/10 of a bit-period, so in your 1Mbit/sec case that is 100ns and about 30m in distance. Once you have multiple observations and can do a least-square or similar fit, often using a Kalman filter or similar to estimate the target dynamics, you can typically get down another factor of 3 or so depending on the geometry (GDOP), so you are looking at under 10m precision.
Plenty good enough for most objects in the sea or air, but not quite good enough to resolve per-lane on multi carriageway roads.
A more modern signal-design and receiver algorithms/structure can easily achieve 10cm accuracy at the same SNR, without resorting to flywheeling over multiple observations using Kalman. The key difference is being able to use fully coherent tracking across the signal paths, which putting GPS receivers in the way prevents. However, I am interpreting that you are fully aware of that, may be involved with either bidding or project decisions, and are defending an ESA pre-selected system architecture, so I’ll leave it there.
Be aware that a non-European player is preparing to offer similar service at 10cm accuracy.
You will still have the 'normal' GPS issue that Lat & Long will be far more accurate than altitude.
With so many sources of RF on the ground compared to airborne, and with such variation in topography the system is going to need to be very discriminatory about what RF signals it chooses to listen to.
I wonder if it will be better to require an encoded RF signal that is always on and beyond control of the crew to be transmitted from all aircraft. Then useful data can be included, like real time flight and position information. Maybe somebody should invent Mode S/ADS-B.
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