[HN Gopher] Farmers 'crippled' by satellite failure as GPS-guide...
___________________________________________________________________
Farmers 'crippled' by satellite failure as GPS-guided tractors
grind to a halt
Author : mhb
Score : 104 points
Date : 2023-04-20 17:56 UTC (5 hours ago)
(HTM) web link (www.smh.com.au)
(TXT) w3m dump (www.smh.com.au)
| fortysixdegrees wrote:
| In the unlikely event any Aussie or NZ farmers are reading this,
| it costs less than $1k to setup your own base station and
| transmit corrections via a number of RF links. One base station
| is good to a radius of about 60km, so not enough for large
| ranches but fine for crops. You can setup as many as you need,
| then no reliance on L band SBAS
| fanf2 wrote:
| This article doesn't make sense because Inmarsat-41 is not a GPS
| satellite, so the farm equipment must have been relying on it for
| something other than "their GPS signal". It would be nice to know
| what that something was, so that similar single points of failure
| can be avoided in the future.
| boringg wrote:
| Hope they have insurance thats covers GPS failure...
| jabradoodle wrote:
| It's terrifying to think what could happen with a mass coronal
| ejection or some other catastrophic event. When you see events
| like this and the Ever Given incident.
|
| We've built a very complex distributed system that lacks
| resiliency in some very serious ways.
| cellularmitosis wrote:
| This is perhaps a hyperbolic. Self-driving tractors can always
| be driven by hand when needed.
| ineedasername wrote:
| It amazes me that we've been able to fine tune optimal
| agricultural practices to the point the a GPS system is a key
| tool in precision & optimized land usage.
| uniqueuid wrote:
| It's kind of surprising that single satellites can still be so
| crucial, given that we have at least three operational navigation
| systems which phones can easily use (GPS, GLONASS, BeiDou and
| Galileo). Are those not all truly global?
| abfan1127 wrote:
| While these may be truly global, I don't know that all "GPS"
| satellites are. They reference a specific brand of satellites.
| Their website mentions that this satellite only services the
| asian pacific region.
| bluGill wrote:
| This is a navigation satellite, it is a communication satellite
| that sends information you cannot get via GPS. The speed of
| light in the atmosphere is not a constant, this satellite is
| sending corrections so you can account for that (that is there
| is some other GPS 'near' you, at a known location, and then it
| compares where GPS says it is to where it really is and you
| subtract that difference).
| fsckboy wrote:
| I'm a little too lazy to read the article (I'm not super
| interested, and I'm sure experts are solving the problem as we
| speak) but I'm curious about "gentle degradation" or "fail-safe"
| modes: If the satellite/location correction data is not
| available, does the positioning just get worse by (I think I
| read) 4%, or did they not anticipate this type of failure and the
| equipment is actually stuck and useless?
| michaelt wrote:
| The tractor can always be driven by hand. Tractors have not
| literally "ground to a halt".
|
| The systems that have failed are those using GPS with
| differential corrections, which achieve ~2cm accuracy for
| 'precision agriculture' (tractor auto-steer, making efficient
| use of chemicals by only spraying them precisely on the plant,
| etc)
|
| The degradation is they now only have normal GPS which is
| accurate to within a few meters - but that's useless for
| precision agriculture.
| eschneider wrote:
| This is literally my day job. It's a gentle degradation.
| pinewurst wrote:
| What does Inmarsat (failed sat is Inmarsat-4 F1) have to do with
| the GPS constellation which is US Government operated?
| oakwhiz wrote:
| This seems like a great use for having a differential RTK GPS
| receiver at a known good location at the edge of a property. Once
| it's set up, the moving receiver can use the stationary receiver
| as a source of correction instead of relying on SBAS or WAAS.
| bluGill wrote:
| So long as the known location GPS has power, hasn't been hit by
| lightening, hasn't be stolen by local kids, and the radio
| signal can reach your GPS (this is a big one - some farmers do
| this, but they have one GPS at home and sometimes it cannot
| reach all the fields), or any other the other things that can
| go wrong.
| causi wrote:
| _Katie McRobert, general manager at the Australia Farm Institute,
| said Australian farmers sourced their GPS signal from one
| satellite, which was a critical risk to rural industries._
|
| _All that went out the window when the Inmarsat-41 satellite
| signal failed._
|
| Can somebody who actually knows what happened fill us in? Because
| saying you depended on _one_ satellite for GPS makes no sense.
| Based on the article as-written, this is headline is wildly
| misleading. The tractor failure has fuck-all to do with GPS. It
| sounds like their satellite data link failed and the tractors
| shut down without a control signal.
| tivert wrote:
| > Can somebody who actually knows what happened fill us in?
| Because saying you depended on one satellite for GPS makes no
| sense.
|
| I have no real knowledge of this, but maybe they were relying
| on that satellite to transmit DGPS corrections for their region
| or something, to improve accuracy.
|
| Edit: Found this while replying to a now-deleted comment:
|
| Even if it's not exactly DGPS, it seems like it's some kind of
| accuracy-improvement service:
|
| https://www.abc.net.au/news/rural/2023-04-18/inmarsat-i-4f1-...
| :
|
| > He has got a workaround for now, using the old free-to-air
| GPS that is a lot less accurate, but he said he was
| disappointed with the lack of information on the outage.
|
| IIRC, regular GPS positions have an error of at least a few
| meters, which is not good enough if you're trying to plant
| crops.
|
| Edit2: Just digging around, I found this:
| https://en.wikipedia.org/wiki/GNSS_augmentation#Satellite-ba...
|
| > The Australian SBAS [Satellite-based augmentation system]
| using Inmarsat 41, which famously suffered a failure in April
| 2023.[6][7]
| [deleted]
| MarkusWandel wrote:
| The article does say that without the GPS service, they are 4%
| less efficient (in terms of slightly overlapping swathes of
| seeds/fertilizer/whatever) and this is enough to be
| uncompetitive. Back when I was a kid on a family farm, accurate
| within 4% would have been great (with manually driven
| tractors)!
| Animats wrote:
| It's a commercial GPS correction service. It corrects for
| atmospheric conditions which affect RF propagation slightly.
| There are many ground stations which receive GPS. They send
| correction info to an uplink station which rebroadcasts
| corrections using a geosync satellite. These services are
| regional, not worldwide, since they need ground stations and a
| geosync satellite with the right coverage.
|
| It's not free; there's a substantial subscription charge.
| Here's one that works in the US.[1] We used Novatel's for the
| DARPA Grand Challenge 20 years ago.
|
| [1] https://novatel.com/products/gps-gnss-correction-
| services/te...
| pstuart wrote:
| Would it not be possible to do a DIY with a collection of mapped
| stationary transmitters? It's not like it needs to learn about
| anything outside the farm in question.
| blantonl wrote:
| Note that this isn't a GPS failure, it's a failure with
| Inmarsat's Satellite-based Augmentation Systems (SBAS), which
| supplements GPS data with signal measurement errors corrections.
| This allows for centimeter level positioning.
| cjensen wrote:
| Sea ports used to broadcast a local correction signal[1] back
| when GPS was intentionally less accurate. Seems like an
| oversight that farms don't have their own correctors.
|
| [1] https://en.wikipedia.org/wiki/Differential_GPS
| bradknowles wrote:
| Farms easily could. You can get GPS RTK kits that cost less
| than $1k and you could set that up at a central location,
| with wired power systems, etc.... it could calculate its own
| position down to the centimeter, and then you could use that
| to help provide correctional information to other clients.
|
| SparkFun has some kits in this space, but you can easily pay
| up to $10k or more for a more commercialized system that is
| designed for surveying, or other related purposes.
| Analemma_ wrote:
| Phones and other devices with cellular radios still use
| differential GPS by way of the cell towers (which have known,
| fixed positions) to do those corrections. You can notice this
| because, when you don't have a cell signal, your phone is
| considerably slower to get a GPS lock and less accurate when
| it does. Presumably these farms are out in the middle of
| nowhere and so that's why they can't do the same thing and
| need a satellite-based augmentation instead.
| 747fulloftapes wrote:
| Most modern cellphones use AGPS, assisted GPS, to reduce
| the time to get their first fix. Basically, AGPS primes the
| GPS receiver with an accurate time of day and the GPS
| almanac (satellite ephemeris data). That's rather different
| from Differential GPS, which is basically corrections used
| to compensate for fluctuating conditions in the atmosphere.
|
| I may be wrong, but I don't know of any system for cell-
| tower derived corrections being redistributed out as GNSS
| corrections. Could you clarify the specific system you
| described?
| fortysixdegrees wrote:
| Not so much. Modern GPS will get a first fix pretty
| quickly regardless, you don't need to seed it.
|
| AGPS is used when satellite coverage is poor, like urban
| canyons in a city, also a situation where there are a lot
| of cell towers and triangulation is somewhat useful
| bri3d wrote:
| AGPS refers to a specific set of technologies, MSB where
| the almanac and time seed is provided over the cellular
| network, and MSA where the unit sends GPS data to the
| AGPS server and the server solves for location using
| whatever data it would like (which can include a
| multitude of corrections).
|
| I think what you're referring to with cell tower
| triangulation (and also WiFi location, etc.) is generally
| referred to as "hybrid location service" and is usually
| done at a higher level (ie - in software) using AGPS as
| one input to a sensor fusion algorithm.
| marsokod wrote:
| The time to first fix is mainly impacted by whether the
| receiver knows which satellites to listen to. This
| requires two things: having the ephemeris for the
| constellation (either 10min of listening to GPS signal,
| or getting that through AGPS), and it's approximate own
| position/time (done through cell antenna locations, and
| NTP) to know which satellites should be visible.
|
| Once this is available, the receiver can then focus on
| the signals that are expected and will then be able to
| provide a 3D fix as soon as it receives something from 4
| satellites, which would be in a few seconds.
| bri3d wrote:
| A-GPS can run in Mobile Station Assisted (MSA) mode,
| where the device sends raw GPS data to the A-GPS network
| and the assistance server processes it. In this
| situation, the assistance server can use whatever precise
| cell site location and ionospheric correction data it
| wants in its processing, although this is more of an
| "exercise left to the implementer" and I'm not sure sure
| MSA mode is even very common anymore.
| labcomputer wrote:
| Not quite. Phones use _assisted_ GPS, which means that they
| download GPS ephemeris data over the internet instead of
| getting it from the the satellite signal (because the
| satellites transmit data at 50 bps). So the time to first
| position is faster.
|
| Differential GPS, by contrast, transmits the difference
| between the surveyed location of a base station and the
| GPS-derived position of the same station. That offset can
| be used locally to correct other nearby GPS receivers.
|
| Phones also use trilateration on the cell tower signals to
| get an approximate solution before trying to solve 3d+time
| on the GPS signal.
| wepple wrote:
| It makes me unreasonably happy to see someone call it
| trilateration. Then again, you appear to know what you're
| talking about.
| UncleEntity wrote:
| > Presumably these farms are out in the middle of nowhere
| and so that's why they can't do the same thing and need a
| satellite-based augmentation instead.
|
| Easily maybe.
|
| I can't see any reason someone can't take a stationary GPS
| enabled device and use that to broadcast the differential
| between received location and actual location. Probably
| could do it for less than $20 in equipment. Add multiple
| units and get triangulation for free.
| fortysixdegrees wrote:
| Cell towers have no relation whatsoever to any of the
| different types of differential GNSS
| outworlder wrote:
| Thank you, I was very confused as to why a single satellite
| failure would have had any impact.
| dingosity wrote:
| Lol. I clicked "discuss" to make this exact point. Glad to see
| HN readers are up on which satellites do what.
| 747fulloftapes wrote:
| Specifically, it is the AU/NZ SouthPAN SBAS that's delivered
| via Inmarsat. They use PRN 122 for the corrections.
|
| https://www.ga.gov.au/scientific-topics/positioning-navigati...
|
| For details:
| https://www.ga.gov.au/__data/assets/pdf_file/0011/123320/SBA...
| giantg2 wrote:
| Seems one could use GPS for less granular positioning and then
| use visual landmarks like the soil/crop edge from the prior
| pass or row locations to align for the next pass.
| bluGill wrote:
| The point is to be accurate to within 2cm across the whole
| field, for the entire year. You cannot do that with landmarks
| and human driving.
| Groxx wrote:
| It's probably something that pays for itself reasonably
| quickly too. Minor human wobbling means more difficulty and
| damage when harvesting, probably a wasted row or three per
| field, etc. Add that up over a decade and many, MANY acres
| of fields and it's probably a lot of money.
|
| Precision enables a lot of savings.
| HeyLaughingBoy wrote:
| On /r/farming yesterday someone was showing how he uses
| John Deere's AIG (Active Implement Guidance) to come back
| after seeds have germinated and basically put "pockets" in
| the ground to allow water to pool around the seedlings. The
| accuracy that it requires to do that without damaging the
| plants is amazing.
| giantg2 wrote:
| I'm talking about computer vision using the visual
| landmarks for the fine tuning.
| causi wrote:
| Interesting that whatever technology underlies the SBAS system
| isn't just integrated into GPS. It would be nice to be able to
| map property lines with just my phone.
| kylehotchkiss wrote:
| We don't want other countries weapons guided by our gps
| satellites!
| LeifCarrotson wrote:
| This isn't 1993 anymore. Beidou and Glonass (and Galileo)
| are global networks that do the same things for those other
| countries, and the ITAR restrictions on GPS receiver
| altitude and velocity are increasingly able to be overcome
| by a hobbyist in a garage, much less a nation-state.
| bluGill wrote:
| It doesn't matter - the speed of light in air varies by
| enough that no satellite can provide the needed accuracy
| alone.
| fsh wrote:
| Not quite. Geodetic GNSS systems use two different
| carrier frequencies to measure and correct for
| atmospheric dispersion. This reduces the error to sub-mm
| levels. The inaccuracy of real-time GNSS is due to
| unknown variations of the satellite orbits, satellite
| clocks, and earth rotation.
| bradknowles wrote:
| There are GPS RTK systems designed for use by surveyors. They
| can cost over $10k, but you can also get much cheaper kits
| that you can put together yourself from SparkFun -- like less
| than $1k, easy.
| sumtechguy wrote:
| You can use the cell towers to assist in mapping it correctly
| too as they are fixed position and the location is well
| known. Pretty sure the QCOM patents on it are out of patent
| by now. Not sure if the android/ios api will expose the whole
| list of towers the chip can see though. The chip can do it
| though.
| MikeDelta wrote:
| It seems that GPS signals can be used for higher accuracy if
| the receiving equipment uses two frequencies instead of one.
| This can freely be done by civilians, but requires more
| expensive equipment. Perhaps this solution with SBAS requires
| a cheaper setup?
|
| https://www.gps.gov/systems/gps/performance/accuracy/
| nradov wrote:
| Multi-frequency GPS is already available in many
| inexpensive civilian devices such as smart watches and cell
| phones. It improves accuracy a little, primarily when the
| device doesn't have a clear view of the sky like when next
| to buildings. But it's still not as precise as SBAS.
| michaelt wrote:
| The highest precision GPS receivers require dual-
| frequency reception and perform "carrier differential
| GPS" - any time people are talking about GPS with 2cm
| accuracy, that's what they're talking about.
|
| The GPS signal has a digital signal (with a wavelength of
| ~300m) modulated with a sine wave (with a wavelength of
| ~20cm) - you can measure the 20cm signal much more
| precisely than the 300m signal, but it's 'ambiguous'
| because it repeats every 20cm and you don't know how many
| waves of the sine have passed.
|
| If you can receive two frequencies, giving you two
| slightly different sine waves, you can multiply them
| together and get a sine wave with a longer period, which
| (together with some clever maths) lets you bridge the gap
| between the unambiguous-but-imprecise digital signal and
| the precise-but-ambiguous sine wave.
|
| You also need a fixed base station at a known location -
| or access to a commercial network of such stations.
| AlotOfReading wrote:
| The US government _does_ provide an SBAS called the WAAS,
| operated by the FAA. It 's also had a hand in designing and
| operating a number of other augmentation systems [1],
| including CORS, GDGPS, and NDGPS. As an aside, don't you just
| love how many government acronyms there are?
|
| [1] https://www.gps.gov/systems/augmentations
| tesseract wrote:
| WAAS doesn't cover Australia.
| AlotOfReading wrote:
| Wasn't saying it did. MSAS (Japan) can be used in AU if
| you accept the performance degradation, but the lack of a
| public SBAS for the southern hemisphere is a big reason
| why SouthPAN is being brought online.
| ericpauley wrote:
| FAA sure loves their TLAs. Some acronyms (or initialisms,
| for the pedants), like VOR, are TLAs _inside_ TLAs!
| Waterluvian wrote:
| Typically these systems are broadcasting data obtained from
| many private regional reference stations on the ground. Look
| up "VRS RTK" as an example.
| tick_tock_tick wrote:
| The article says GPS but it looks like they are using a special
| satellite by Inmarsat rather then the USA military GPS.
|
| I've very unclear why they are using this one specifically rather
| then GPS or GNSS. Or even a combo if the Inmarsat has uniquely
| good properties?
| fortysixdegrees wrote:
| Ive been working with GNSS for the last decade and a bit, and
| this article and the comments here are a low point for HN in
| terms of people making comments about stuff they dont understand.
|
| PSA: if you want to learn about corrected GNSS, stop reading this
| thread now. I started replying to some comments then gave up,
| most here are more wrong than right.
| wepple wrote:
| Do you have any suggested resources? It deeply fascinated me
| but books seem either highly specific or academic
| fsh wrote:
| Physics articles are even worse. Commenters on HN are mostly
| science-illiterate but have very strongly held opinions.
| LinuxBender wrote:
| As others mentioned this sounds unrelated to GPS. Have any
| colleges been working on a _local_ and _self hosted_ server /
| transceiver to control tractors and remove this _single point of
| success_? Maybe even take GPS out of the equation by having
| perimeter or fence-line beacons to create a virtual map for the
| tractor? Bonus if someone made a kit to retrofit old tractors. I
| could have some fun with my 1947 Fordson 2N driving itself.
| myself248 wrote:
| I can't imagine relying on private SBAS when DIY RTK is so
| cheap and easy now. Sparkfun will set you up with your own base
| station hardware for under $1000, I wonder what a year of
| inmarsat corrections costs.
| michaelt wrote:
| Historically (perhaps prices have come down a lot in the last
| decade with the introduction of the L5 signal?) getting RTK
| corrections from a third party meant you only needed one
| $20,000 receiver, instead of two.
| gravitronic wrote:
| What an insane dependency tree, that driving a truck in a field
| to plant some seeds requires a computer operating in space. I
| really hope there is a push-back on this unbounded complexity.
| Mind boggling.
| outworlder wrote:
| > What an insane dependency tree, that driving a truck in a
| field to plant some seeds requires a computer operating in
| space.
|
| Well, what if I told you that, if GPS failed, many other
| (stationary!) operations would be impacted? Including
| financial.
|
| We rely on space computers for more than position, we also rely
| on them for accurate timekeeping. If you are connected to the
| internet you can get time corrections that way, but there's
| plenty of devices that are gathering time data from space.
|
| Now, the issue here is not so much that they are using
| satellites, is that they are _only_ using satellites (and, it
| would seem, they are using them for the entire time they are
| operating). Land-based stations around the field to provide
| location information could definitely be used instead. Or other
| mechanisms.
|
| I don't know if tractors have inertial navigation units but, if
| not, maybe they should. That would at least allow them to
| operate after the initial fix was established (which doesn't
| even require GPS, just a well-known starting point). Basically,
| the same thing that airliners already do.
|
| EDIT: found this - https://www.digikey.com/en/articles/use-
| inertial-measurement...
| kube-system wrote:
| It's only silly if you have an outdated "romanticized" image of
| farming in your head. Those images are from a time when >50% of
| the population farmed. Technology is what has enabled the vast
| majority of people in developed societies to do things other
| than farming.
| benj111 wrote:
| There's a massive gap between >50% of the population farming
| and GPS guided tractors that apparently don't need a driver.
|
| Edit: I say don't need a driver, or whether they always
| needed a driver who now just needs to drive, but that to me
| doesn't constitute 'crippled'
| kube-system wrote:
| Yes, and that divide includes genetic engineering, weather
| satellites, teams of chemists, million dollar tractors, a
| finance and logistics infrastructure, and a whole lot of
| other stuff that doesn't look anything like American
| Gothic. GPS guided tractors are not remarkable in that
| continuum.
| mistrial9 wrote:
| this thinking in the previous industrial age created the
| poison wastelands of Ohio. Mudslinging with the tag
| "American Gothic Farming" adds to the arrogance of it
| all. American farming is largely a flaming disaster on
| top of destruction, with other would-be plantation owners
| racing to copy it. Plenty of blame to go around, and this
| contrite endorsement of all and anything futuristic,
| ain't the cure.
| kube-system wrote:
| Famine kind of sucks too.
| HeyLaughingBoy wrote:
| Mic drop :-)
| mardifoufs wrote:
| The article is about Australia. There's no need to go on
| a self-loathing rant about where you live.
| tedunangst wrote:
| I'm pretty sure we got below the 50% farmer threshold without
| using GPS. Or has this all happened in the last twenty years?
| kube-system wrote:
| I'm sure someone was scoffing at how "ridiculous" it was
| the first moment a farmer took a Tin Lizzy into the field
| and it needed a new clutch. Technology "in the field" is so
| normal that it is an idiom.
| bluGill wrote:
| Your image of the farm is from when >50% of the population
| farmed though.
| tedunangst wrote:
| My image of the farm is from when about 2% of the
| workforce farmed. I don't think self driving tractors
| have changed it that much.
| bluGill wrote:
| You are usual then.
| bluSCALE4 wrote:
| Right but they probably had 10x farm hands and no yield
| contractual agreements.
| dokem wrote:
| Everything is already complex. The rubber in the tires,
| foundries for the metal in the tractor, machining tools and
| welding equipment, the processes and tools to develop
| insecticides, water infrastructure. Why is a far away radio a
| bridge too far? It already takes a nation to build tractors at
| scale.
| gravitronic wrote:
| If the tire factory takes a day off, the truck in the field
| can still drive.
|
| If the rubber factory takes a day off, the truck in the field
| can still drive.
|
| etc, etc.
|
| Can't talk to a specific single space computer with no
| fallback? truck in the field might as well be a potato.
| politician wrote:
| Fuel is complex.
| albatross13 wrote:
| You should start your own farm and scale it to feed tens of
| millions of people, simply by driving a truck in a field :)
| jasonpeacock wrote:
| They aren't driving a truck, the truck is driving itself and is
| guided by a high-resolution GPS-like service.
|
| Providing a high-resolution GPS-like service at affordable
| scale is not simple.
| klyrs wrote:
| One can imagine planting a few posts at the corners of a
| field with a few dollars worth of radio equipment each, and
| getting higher resolution without relying on satellite.
|
| Reading other comments here, it seems that these exist, in
| tandem with GPS, to get absolute positioning. But I don't see
| why absolute positioning would be needed; relative
| positioning should suffice.
| j16sdiz wrote:
| It worth a lot more than "a few dollars"
|
| Most technology give you 20+ cm resolution[1], the one
| farmer are using are at ~4cm resolution .
|
| [1] https://link.springer.com/article/10.1007/s11277-021-08
| 209-5
| klyrs wrote:
| I was thinking of component cost when I said a few
| dollars; of course a commercial product is going to sell
| for thousands. In the 60GHz band (IEEE 802.11ad), you can
| plausibly get down to ~.5cm resolution with cheap, COTS
| network gear.
| bluGill wrote:
| The labor to make that work is going to be expensive, but
| yes you can do that. GPS with corrections is the cheap and
| easy way to ensure everything works and then you get back
| to the business of farming.
| thebooktocome wrote:
| I think a more charitable read of OP is that you don't need a
| satellite (or even GPS) to provide centimeter-accurate
| localization over a wide area. Spacebound systems are always
| going to have worse uptime and less resiliency than ground
| ones.
| yardie wrote:
| This is not the USDOD GPS. This is Inmarsat's DGPS service that
| provides ~1-2cm accuracy. Which, if you're driving between rows
| of produce can be the difference between harvesting or crushing
| crops.
|
| [0]https://en.wikipedia.org/wiki/Differential_GPS
| polishdude20 wrote:
| What's stopping farmers form getting better local location
| determination by using RTK stations around their field instead?
| cellularmitosis wrote:
| Certain manufacturers fighting against right-to-repair
| certainly stymies potential third-party hacks / upgrades,
| such as your suggestion.
| JoeAltmaier wrote:
| You can put devices in the field that substitute for the GPS
| satellites. But you have to know where the device is! So it'd
| have to have been installed before the outage.
| Animats wrote:
| That used to be done. They're called "psuedolites". You'd put
| one somewhere on your property. It listens to the GPS
| satellites, and over a few hours, gets its own location very
| accurately by averaging error. Then it rebroadcasts a
| correction signal to cooperating GPS receivers nearby. Some
| airports have used these. They're called "ground based
| augmentation systems" in aviation.
|
| There are agricultural versions. Deere sells some.[1] They call
| this "RTK".
|
| [1] https://www.deere.com/en/technology-products/precision-ag-
| te...
| skybrian wrote:
| The article is from two days ago. Here's another article saying
| the satellite is at least partially back online? I don't know if
| that helps farmers, though.
|
| > Inmarsat's aircraft safety and other L-band satcom services for
| the Asia-Pacific region are operable again, following an outage
| of the firm's I-4 F1 satellite which forced operators to switch
| to high frequency (HF) radio. The news comes as a relief to
| operators, pilots, aviation enthusiasts and tech-savvy flyers.
|
| > London-based Inmarsat explains in a fresh update today that the
| L-band satellite "suffered a partial loss of power" which invoked
| automatic procedures on the satellite that led to the suspension
| of services for East Asia and the Pacific region starting at
| 21.14 UTC on Sunday 16 April.
|
| https://runwaygirlnetwork.com/2023/04/inmarsat-safety-servic...
| skybrian wrote:
| Another article:
|
| > The British satellite Inmarsat I-4 F1, which provides
| services for East Asia and the Pacific regions, is back in
| operation after an outage on Sunday.
|
| > The incident is prompting farmers and industry groups to
| examine their backup systems for the technology they are using.
|
| Questions raised about reliance of satellite technology for
| farming after Inmarsat I-4 F1 outage
| https://www.abc.net.au/news/rural/2023-04-19/inmarsat-i-4-f1...
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