As someone who was recently a delivery driver, the recent addition of GPS tracking is one of the most annoying things about a delivery job. Far worse than drug testing. Driving can be difficult and sometimes you need to park and stretch your legs. I was called into the office for this and queried about each of my stops. GPS is going to become more prevalent as people like me are highly motivated to defeat the system, especially working in teams with other drivers. Of course there are work-arounds. Park at a legit spot on an approved break and leave all your electronic devices in the vehicle and walk to where you want to be but don't want them to know about, etc...
However, it is highly doubtful this was done by a delivery driver. There is no point in jamming the signal for 10 minutes. What could it accomplish? If the purpose is to take an illegal detour (going against a one way street) the company has logs of all your trips and will soon figure why you have a 10 minute gap everyday.
Courier companies are going to have to wise-up pretty quickly and realise that the operational benefit to accurate GPS tracking is far too important to risk using as an HR tool.
At the end of the day, route optimisation can make or break a courier company, and getting good metrics on driver routes is just as important as getting (for example) tracebacks on your errors when coding.
The smart companies will take a no-blame approach: a driver is responsible for his route with the assistance of the intelligence provided by the company. Any follow-up should be constructive, and the good drivers will feed information back to improve the system.
There is no way it should be used to check your break schedule, and any operations manager should be coming down like a ton of bricks on anyone who is undermining such an important tool in their business.
I didn't work for a top tier company. Both companies I drove for had incompetent management all the way up to V.P. level. They were petty, stupid, and they sure as hell will use GPS tracking as a punitive tool.
I think the parent means that the person who is driving past the LSE with his jammer is less likely a delivery driver, as they are under close scrutiny but rather anyone else.
Might as well be anyone who'd rather not be tracked if they can help it. I can imagine perhaps a VIP or even an organized crime member who prefers their car free of GPS trackers when they drive around town visiting associates.
It's even less likely he jams signals where ever he goes and LSE just happened to notice it. His company would be very curious why he was disappearing. They can pull him on a screen and watch when he goes in and out of range. It would happen only to him, in whatever vehicle he happens to check out that day. A driver would have to be far more clever than that.
The article states "timestamps on trades made in financial institutions can be affected" There's your likely culprit; someone who for whatever reason needs to affect timestamps.
I think it's likely a driver who is constantly jamming his GPS. I have seen this in work with the FAA. A driver will go past the airport or park and deliver something. We see a temporary GPS outage which have traced back to delivery drivers in several instances. I imagine their company assumes their GPS equipment is broken, but still lets them drive.
It seems like an airport would be pretty eager to identify and prevent this so it doesn't go on. Maybe the London Stock Exchange doesn't care as much, but if it messes with trades?
I'm curious as how this disruption could be used in a financial scenario. If you disrupt the GPS for 10 minutes, would the timestamps really go that out of whack?
And more importantly, will they go out of whack in a way that's useful? Being able to shift the timestamps a few microseconds could be quite valuable if you can do it only to your order gateways (and ensure it's in the correct direction) but "jamming GPS" doesn't seem to get you that. I'm not going to say there's nothing it could be used for, but it's not jumping out at me.
> Driving can be difficult and sometimes you need to park and stretch your legs.
If your employer doesn't allow legally required breaks you can use the GPS log in your suit against the company. Otherwise it sounds like you weren't doing your job.
Pulling over his delivery truck to go on a walk does indeed sound like not doing his job as a delivery driver. I don't see many UPS drivers going for jogs during the day...
> I don't see many UPS drivers going for jogs during the day...
What a horrible example. They actually get up and walk around probably dozens of times per day. That is completely different from long-haul trucking, where you may only get 2 stretch breaks in a 10 hour period.
Not all delivery drivers are package delivery types. There are a lot of other types of company vehicle drivers like medical equipment delivery and service. I imagine all company and govt vehicles are headed towards GPS tracking and logging.
I had a long career programming computers and decided to take a break from it and do something completely different. I had two different driving jobs (because I like to drive.) I was shocked beyond belief at how employees are treated as machines and worse for not much pay.
Everyone should have shitty jobs for at least a month or two growing up. When I was doing my degree in mechanical engineering after my first year I had to do this internship in this manufacturing plant in France. I was basically a factory worker. It really sucked. But it kind of put things in perspective. I knew that in a few months I'll be back in the school doing awesome stuff but for most of the folks there being treated like shit for next to nothing was pretty much everything life had to offer.
Then one day the entire plant and all the workers have been replaced with a few industrial robots.
Agreed. I did a stint in a cardboard box factory. I put the lid on a box that came out a machine. 1 per second for an 8 hour shift. Clock in clock out. Management sat in an office above the shop floor and waited for infractions to punish it was soul destroying.
I agree with this. My dad's a surgeon, and he tells me sometimes how he frequently hears many other doctors complaining about their job. He says the only reason they complain about a great job which gets them immense social respect, pays $300k+ in a very cheap rural area, and has rock-solid job security is because they've never known anything worse. It's the only job they've ever had. Most came from well-off families and never worked through high school and college at all.
> I was shocked beyond belief at how employees are treated as machines and worse for not much pay.
My brother is a long-distance driver, and while on a short vacation (I'm a programmer) I took the chance of accompanying him in one of his job trips. While you sit in the right-sit as a passenger everything seems nice and beautiful, but then you notice the driver's stress of not making it in time, or how he just tries to "trick" the system "just that little" so that he'd make to the destination without exceeding the allowed gas limit, and lots of things like that. For comparison us programmers have it relatively easy.
It can be really stressful. Once I had to detour due to an accident. I forgot about it but was called in 3 months later and threatened with a firing if I couldn't explain it. Fortunately I remembered, but I learned after that to keep a personal log.
I alternate between working as a programmer, and working as a salesperson in a retail store. Keeps me grounded, and helps with pitching.
I think everyone should work jobs like these, something different, to give a better perspective on life and exit the echo-chamber for a while :)
Of course, it will depress a lot of us who have grown up expecting to be treated like royalty due to our skills. Thankfully, if you're a great (top 1%) salesperson, you can still get that, but it takes a tonne of hard work to get there!
You sound like you work in management. The attitude is that these types of jobs are unskilled and that electronic performance indicators are appropriate.
Let's take the job of a bus driver in a major city, which I did for a year. Everyone is out to get you. People try to stop short in front of you so you'll hit them and they'll collect insurance or they're trying to commit suicide. Drivers always try to get around you and beat you causing dangerous conditions. Passengers complain constantly and look for reasons to sue. Passengers get sick and throw up on your bus. Management sets impossible standards, so if for example you are late due to traffic it's too bad if you need to pee at the end of one trip (where you normally get a 10 minute layover to smoke and pee) because they make you turn right around and catch up. City monitors ride the bus to evaluate everything you do. Company monitors do the same. Passengers call the company and complain if they dont' like you. Cameras are on all the time in the bus and you will get called in and questioned about anything that happened on your shift. City police won't hesitate to write you a traffic ticket. You can have two "incidents" a year before you are fired. It was the hardest job I ever did, but the most rewarding because I made the grade and didn't wash out, and on a good trip (once around) it was very Zen being the calm meditative driver (which is state the job forces you into) All for 12 dollars an hour.
Thanks! I recommend anyone try it in a big city. It's really the only sane response to what is essentially a real life action game. Focus, keep calm and carry on. You sound like one of my favorite group of riders: We get to know the regulars even if we don't talk and know which of you has our back.
There were far worse reasons to file a lawsuit (such as the company encouraging out right fraud in record keeping) but not many drivers are going to do that. They'd rather just complain and play the game while staying gainfully employed. There are all kinds of subtle ways to get rid of problem drivers. You've heard of Three Felonies a Day? [1] A driver can easily break a lot of driving rules and if the company wants to be strict about it, you're gone.
don't put your trust in Harvey Silverglate, he's a total liar and manipulator.
Take the first example on the page you linked to, where he claims a woman was sentenced to two years in prison for cluelessly buying lobsters in plastic bags taht should have been packed in boxes. Bullshit: she was sentenced for conspiracy, mislabeling of produce, and violations of the Lacey act for illegal harvesting of underage/undersize lobster, in defiance of Honduran laws designed to preserve their fisheries, over a 5 year period. The feds didn't set out to prosecute Huang; they were approached by Honduan authorities and asked for help in stopping the illegal fishing activities. See https://bulk.resource.org/courts.gov/c/F3/331/331.F3d.1228.0... for the appeal court judgment - and ask yourself why Silverglate doesn't provide his readers with a link to the judgment or even an accurate summary of the indictment.
Every single case I have ever seen Silverglate cite involves a similar level of misrepresentation on his part.
I interviewed Harvey Silverglate while he was writing his Three Felonies book and came away with precisely the opposite opinion. Harvey is hardly a "liar and manipulator." He was EFF's first attorney and is one of the leading civil liberties attorneys of our time.
I interviewed Harvey Silverglate while he was writing his Three Felonies book and came away with precisely the opposite opinion. Harvey is hardly a "liar and manipulator." He was EFF's first attorney and is one of the leading civil liberties attorneys of our time.
GPS signals come from satellites. AFAIK there are about 20-40 GPS satellites. Let's say each covers at least 1/50 of the Earth's surface area, about 500 million km^2. That's 10 million km^2 per satellite.
What's the max power generation you can fit on reasonable-sized satellite that's going to be in orbit for decades? I'm guessing not more than 10 kW. So 10 kW / 10 million km^2 means you have .001 watt per km^2.
GPS signals being easy to jam isn't surprising. What's surprising is that you can detect them with equipment that's small and cheap enough to fit in a cellphone!
Where it really gets amazing is when you discover that the GPS signal is around 20-30dB below the noise floor. That is to say, ambient noise drowns out the signal by a factor of 100-1000. Long-term correlation manages to pull out usable information from this extremely noisy signal.
An interesting consequence of this is that you don't need a very fancy receiver, hardware-wise, because your software already has to be extremely sophisticated. For example, you can use a 1-bit ADC rather than trying to be more sophisticated about exactly how strong the signal is at any given moment.
That's crazy... I think I'll contain my frustration more now when my GPS takes a few minutes for a cold lock. It's even more crazy because with the latest GPS systems in phones, I'm able to get a fix with only a very small portion or even no sky visible.
Interestingly, the cold lock acquisition time is usually gated by the time required to download the almanac from the satellites, rather than acquiring the actual GPS signal. The almanac (which is the stuff that basically tells you where the satellites are, so you can figure out where you are based on that) gets sent on a side channel at a very slow rate, something like 50bps, such that it takes about 30 seconds before you have all the data, and any interruption can mean it takes multiples of that. The main advantage cell phones have is the fact that they can download that data from the cell network rather than waiting for it to dribble in from the satellites directly.
The ability for GPS to (sometimes) work indoors these days is indeed pretty crazy. The signals are already incredibly weak, and you'd think having a roof and walls and pipes and wiring in the way would make it impossible to read them.
Systems that rely on GPS are defective in their design. US military systems have never trusted GPS, since inception, because the Soviets had the ability to destroy the satellites and tinker with the RF.
US military systems are inertially guided only accepting GPS corrections within the error bounds of their extraordinarily tight inertial measurements. If the GPS is outside the error bounds, it is presumed to be compromised. There is no such thing as an intrinsically GPS-guided weapon; they are always inertially guided with GPS corrections. Modern US inertial systems are similar to GPS in terms of precision so GPS is increasingly superfluous.
As a consequence, the US military has never been significantly vulnerable to loss of GPS. Their systems were designed, from Soviet days, to assume that GPS could be compromised or lost since the Soviets had that ability. Knock out GPS and you still have to deal with ultra-precise solid-state optical gyros.
Many commercial systems take a cheap shortcut and rely on GPS but, contrary to popular mythology, US military systems never have.
There is a legendary tale of a how a random delivery truck took down a whole popular MMO.
The MMO company had a issue with their own physical logistics, and had to put their login server across the street in another building.
They put special antennas between the two buildings, to keep the thing running, and it worked great, until one day, it didn't.
After a while trying to figure what was going on, they noticed that a huge delivery truck parked illegally (the place where it parked was illegal to anyone park), and the place he choose made the bulk of the truck metal stay right between the two antennas...
EDIT: Also when internet was still dial-up, one delivery truck ignoring height limits managed to cut all phone cables near my town biggest ISP, leaving the entire city without internet. I did not appreciated it...
I've heard of a similar issue with a wireless data link across a river that would cut out once or twice a day, but not everyday, and no one could figure out why. The answer only came after a few weeks of monitoring and an ametuer fisherman saying "hey, those are all high tide times!" at which point they realise that high tide was causing the mast of a docked boat to rise up enough to interfere, and that the boat was not always in its dock which is why some days were fine.
Yeah, I was hoping it was the ten minutes before market close every day and some evil genius HFT operator was trying to exploit lack of time sync at the exchange.
Same here. If they were really cunning, they could fabricate their own signal with a different timestamp. You could shut down rivals by making their computers believe that the trading day was over, or that their market feed was too slow to trust...
Most people are using GPS-disciplined oscillators, not raw GPS clocks, so don't need GPS coverage except for very long-term stability. The crystal in the oven stays plenty stable over the timeframe of hours and days, and takes priority over any shady-seeming GPS updates. The worst you can do is cause a loss of a few ppm clock stability. (These are only $200 on eBay and I have one at home. From time to time I have a bad GPS signal and my consumer-grade ntpd marks the GPS clock as a "false ticker" and falls back to the PPS signal only.)
You could do that over very small timeframes (say, a millisecond earlier or later) but most systems don't automatically adjust times if the delta is very large
For regulatory purposes, milliseconds are negligible. FINRA allows for up to 3 seconds of divergence from standard time sources.
For deep alpha signals, a millisecond is pretty negligible (especially when you are calculating minute or 10 minute bars).
For microstructure trading strategies, since the timing doesn't manipulate the book (which is where most microstructure trades derive alpha from), the effect is similarly negligible.
And for cross-exchange and cross-asset arbitrage, where microseconds may seem matter (regnms), slight drifts are permissible insofar as you can plausibly argue that even if the clock is slightly off, your view of the market is internally consistent
It sorta drives home how vulnerable the systems are. If someone can do it accidentally, the what could a malicious, well resourced attacker do? How come a well resourced attacker hasn't done it?
Should it not be possible to track the vehicle (if it is only one) by installing GPS receivers in the area and noticing when the disruption begins and ends for each receiver?
That, coupled with license plate scanners at those locations, ought to find the culprit.
(And then they can launch an armed drone to take him/her out...)
The culprit is basically shining a very bright light (at invisible frequency) in all directions. Catching them should be even easier than your proposal.
(I suppose one could program a missile to follow the light...)
GPS satellites broadcast 500 watts from a 13dbi antenna.
But they're far away. Really really far away, to the tune of 21,000km. (The Earth is about 12,000km wide.)
By the time the signal makes it to the surface of the planet, the inverse square law has punched it down to -130 dBi, which is well below the thermal noise floor of room temp electronics. GPS receivers pull a useful signal out of a storm of random noise using deep information theory magic, which is vulnerable to several clever low power attacks.
Even a dumb jammer doesn't need much power, though.
one could program a missile to follow the light...
"The AGM-88 High-speed Anti-Radiation Missile (HARM) is a tactical, air-to-surface missile designed to home in on electronic transmissions coming from surface-to-air radar systems."
Basically, even though the signal is below the noise floor, part of the signal is the output of a pseudo-random number generator with known properties, so by setting up your own PRN, and then trying different (time) alignments, the correct alignment will stick out, despite the noise (which all averages out). Once you have the time alignment, you can read the rest of the signal, and then you can tell how far you are from that satellite ((it's clock - your clock) / c).
Repeat for other satellites and you're done.
Can't find any good references, but that's what our information theory lecturer said! Also, it explains why a hot start is quicker than a cold start (if you know where you are, and the accurate time, you know what alignments to try to start looking for the satellite signals.)
GPS signals are unsurprisingly easy to disrupt. It's a location mechanism that depends on one-way communications and triangulating an extremely precisely-timed signal between at least three far away satellites. Position fixes don't rain down like mana from heaven.
Many many years ago I was a specialist in satellites for a major European broadcasting company. We had a problem with couriers who used radar speed trap jamming devices. They had really noisy oscillators which leaked huge quantities of out of band noise into the dished which were located near the courier drop off point.
We initially used an expensive spectrum analyser attached to a spare LNB (pointed at the parking area) but that needed you to notice the noise. So I used a USB enabled RF power meter interfaced to Excel (so sue me, it was a rush job and we weren't equipped for development). A script ran which fetched values, when there was a spike in received power it played an alarm and flashed the screen.
The next step was to ask security to hold anyone in the carpark while a large angry engineer went to give the courier a piece of his mind. It worked, courier companies were informed, people were shouted at and I believe it stopped.
There are probably better ways of doing this, but it was effective and built from spare parts.
There's an Australian company who's got a land based positioning technology. It does not rely on satellites and I think it holds a lot of promises especially for airports.
Land-based, non-satellite radionavigation (particular for aircraft) is older than GPS (or satellites, or even jet engines.) (e.g., VOR, DME, TACAN, etc.)
Interestingly, Google's successor to BigTable -- Spanner -- utilizes GPS clocks and atomic clocks to maintain consistency of their data across globally-distributed data stores.
Also, Google uses accurate atomic clocks in each of their datacenters, so when their GPS connectivity gets cutoff, they can still keep time. Almost everyone does.
Hmm, yes kind of like how a new GPS costs $5K, because the first .mil model did cost that much. Or all computers currently cost millions of dollars because the first ones did.
As somebody who's primary field of study is GPS / Navigation / Positioning, I'd like to remark that survey grade receivers such as in the eLoran stations can cost much, much more than £2,000.
Their price isn't so much the hardware itself, in fact, most of the receivers seen in cell phones today cost less than $1USD. However, when dealing with more accurate receivers, the receivers typically need extensive calibration and testing. I mean, it's possible to get measurements from GPS accurate to 1mm, but you need to have both a careful setup and very good knowledge about the errors associated with your receiver. So yeah, these receivers are actually quite expensive, and most of it is because the calibration on repeatability and stability of these sensors is of the utmost importance.
On a secondary note, survey-grade receivers are typically not as prone to jamming as consumer-grade receivers, mostly because they can use multiple GPS frequencies / can collect over a wider bandwidth. There's a lot more to it than that, but effectively the point I'm making is that the receivers spoken of in the article are not the same as everyday GPS receivers.
If you want to see how crazy the prices on these receivers can get, look no further than http://www.surveyorsmart.com/product.sc?productId=548. I doubt many surveyors would go for that particular model by Leica, as it is definitely expensive, even for survey equipment standards, but it's not unreal in terms of pricing.
So going in the other direction, are there cheap eLoran receivers available? Would one be any use as a backup to, say, someone with a cheap second-hand yacht who occasionally goes sailing?
I don't know of any personally, but I'm going to say probably not. If you're looking for dual band / GLONASS + Beidou support high grade receiver, you're typically looking into the $1000-$10,000 area.
The best I've seen in consumer space so far is (surprisingly) the iPhone 5. Full AGPS and GLONASS support, which is better than most Android phones.
Ultimately, I don't know if I can give you explicit advice on the matter, but I would suggest you search for some way to integrate something such as an IMU into your navigation system, if possible. A properly implemented dead reckoning plus GPS is usually pretty hard to fool, as one of the systems will drop errors as soon as something starts to go wrong. However, getting the proper integration might cost you more than you're willing to pay, so it may just be in poor taste for me to even bring it up.
What we should be doing is replacing $1 GPS receive chipsets in phones with procession positions chipsets, and taking advantage of CORS reference stations (http://geodesy.noaa.gov/CORS/) for sub-centimeter positioning.
you can google the spec sheet for the receiver described. it can measure carrier phase to 0.2mm rms. that translates to an accuracy after post-processing of 3mm horizontal (with a fancy antenna).
the trick is to use the carrier itself, which is higher frequency than the signal modulated on it. also, relative offsets are easier that absolutes (removes many systematic errors).
i wrote (the software for part of) one of these (not for leica, for some geophysical survey company) back in the day (although it was not mm resolution!)
Current GPS receivers have a couple sources of error, including processing slowness and ionospheric delays. If you don't know what the ionosphere looks like, you can't be accurate to 0.2mm. There are ground stations that measure this (based on the fact that they aren't moving so any change in the GPS-calculated position means ionospheric changes) and transmit the correction data to other GPSes, but this doesn't get you to 0.2mm, at least not for a moving object.
TO be fair, Andrew wasn't claiming 0.2mm accuracy in position measurement - he was quoting the devices ability to resolve phase difference in the carrier wave (and noted that is an order of magnitude or so better than the resulting position accuracy).
Having said that, I wonder what the magnitude of ionospheric changes have on the phase difference of the carrier signals from satellites in different directions?
(Even though I know how it works, the idea of getting millimeter precision in measuring distances to something that's at least 20,000km away and traveling at almost 4km/sec seems like very black magic to me… Surely that can't actually _work_ in practice…)
i don't know what current state of the art is and even 3mm sounds crazy good when i think about it (i was just repeating the spec sheet). i wonder if it that also requires separate / multiple receivers to fully model the ionosphere?
As I understand it - once you can get the time-based position fix accurate enough, you add in the phase information from the 1.2GHz carrier wave - with a wavelength of ~200mm, resolving that to 0.2mm seems reasonable.
The problem of working out which of the peak/troughs in the carrier wave you're in almost certainly requires terrestrial DGPS assistance (http://en.wikipedia.org/wiki/Differential_GPS). If you can use that to get ~100mm precision - that allows you to use the phase difference in the 200mm
wave length to get sub mm measurements.
Like I said, I understand how it works – I just find it hard to believe it's actually practically possible… Deep magic…
There is a network of hundreds of (static) GPS receivers to monitor seismic activity. They are post-processed to identify and remove the ionospheric effects you mention.
They used to (ca. 2000) get ~1mm accuracy in the plane of the Earth, and ~1cm accuracy in the radial direction. The accuracy seems to have increased in the meantime, and it appears to be ~0.1mm in the plane of the Earth.
GPS is combined with other sensors like strain meters, etc., into something called Plate Boundary Observatory: http://pbo.unavco.org/instruments/gps
this is actually easier in some ways because it's so slow you can integrate forever and so reduce noise (both "normal" noise and the added stuff, if they are still doing that).
A new GPS made for commercial, certified use (eg. for use in aviation) will cost way more that $5K. Just a software update to it might cost as much. Technology is getting cheaper, certifying it isn't. In don't know about ships, but I assume there is some form of certification for nav equipment there as well.
I don't know about presently, but in the past the GPS transmitters had an introduced error known as "Selective Availability," the purpose of which was to deny pin-point accuracy to unauthorized devices.
For a price, one could acquire the necessary hardware/software to mitigate Selective Availability in order to increase the accuracy of GPS readings, although I forget what those prices were/are.
I remember reading a fascinating article (which seems to elude me on Google right now) about the competitors in the 1990 BOC single handed Around the World yacht race noticing the CEP (circular error probable) on their GPS devices drop from ~100m down to ~10m or better in late July – a week or so before the Gulf War officially started.
They didn't permanently switch off Selective Availability til mid 2000, but they could and did temporarily switch it off when it suited them (and, no doubt, could easily switch it back on today if they thought it worthwhile… They claim any satellites launched since 2008 haven't had SA capability, but I suspect that's only a small-ish percentage of the GPS constellation today…)
GPS used to be that way to give the military access to accurate positioning and provide lower accuracy to others. They can still do this selectively to whole areas of the world should they want to.
The US claim that since 2008 they've been launching GPS satellites without selective availability capabilities.
That means 27 of the current working GPS satellites are older ones which do have SA which could be switched back on at any time, and 12 are newer allegedly non-SA equipped satellites.
Errr, as I read it, the cost is for new eLoran receivers, intended to be an alternative backup to the Mark I eyeball if GPS flakes out for whatever reason. Not going to be widely deployed like GPS receivers, and big ships need reliability ... in fact, the only customers are those who really need this sort of thing, unless it becomes mandated.
There are different grades of GPS receivers, all licensed differently. Consumer-grade receivers have a maximum accuracy of something like 3 meters and a slow response time. There are also aviation grade and military grade receivers, which cost more (build & calibration) but also require a special license.
I interned at Trimble in the radio group. Industrial GPS receivers could be purchased by more / less anyone, however they were built and priced for heavy-duty industrial consumption (mines, farms, ships, aircraft, etc.). The unassisted accuracy without kinematic corrections was around +- 1 m horizonal and ~10 m vertical, constantly changing as the constellation moves. This would be for a top-of-the-line 24 channel parallel receiver. WITH kinematic GPS, +- 10 mm (not a typo) horizonal and ~3 m vertical. It was so good that receivers could be installed on the left and right sides of a grader's blade that the angle and position could be known with great accuracy and precision. Kinematic means a nearby stationary reference ground base station sending updates over radio frequencies to another GPS receiver that could be in motion. This was also used to subtract SA pre-Clinton because the injected error would be the same in nearby locations.
However, it is highly doubtful this was done by a delivery driver. There is no point in jamming the signal for 10 minutes. What could it accomplish? If the purpose is to take an illegal detour (going against a one way street) the company has logs of all your trips and will soon figure why you have a 10 minute gap everyday.