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Super-Accurate GPS Chips Coming to Smartphones in 2018

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Re: Super-Accurate GPS Chips Coming to Smartphones in 2018

#181

Post by StillBored »

The siri/android problem doesn't seem to happen with the dedicated GPS nav systems I have. Maybe its a sample rate problem with phones (trying to save power), or just better smoothing, or relative plotting with the dedicated receivers. 5M is less than the distance between most highways and their frontage roads, so blaming the GPS signal itself for being unable to determine if your on the frontage road 15 seconds after you got on the highway is pretty lame.

I frequently run my ten year old TomTom, alongside my wifes iphone or my android on road trips. The tomtom is pretty much always dead on with respect to lanes/turning/etc, while the iphone/android regularly feeds us crap. That said, I would kill for google maps (pc browser version) style route planning on the tomtom where you can click various roads and get time estimates even if goggle doesn't think its a good route.

Re: Super-Accurate GPS Chips Coming to Smartphones in 2018

#182

Post by throwaway613834 »

MertsA wrote: post #45
deckar01 wrote: post #10

Earlier quoted context omitted.

Things have changed since the 90s. > In May 2000, at the direction of President Bill Clinton, the U.S. government ended its use of Selective Availability in order to make GPS more responsive to civil and commercial users worldwide. > The United States has no intent to ever use Selective Availability again. The military has better precision, only because they buy better hardware. Similar hardware is used in commercial…

>The military has better precision, only because they buy better hardware. That's not true. Military receivers can use the Y Code which is encrypted for military use only. There are some really fancy civilian receivers out there that can leverage Y code to a limited extent without knowing the encryption key but full accuracy is only possible on a military receiver that can decrypt and use the Y code.

> There are some really fancy civilian receivers out there that can leverage Y code to a limited extent without knowing the encryption key

Would you have links to any examples?

Re: Super-Accurate GPS Chips Coming to Smartphones in 2018

#183

Post by gpsGuys »

cantagi wrote: post #84
jtolmar wrote: post #69

Earlier quoted context omitted.

I've been working on GPS filtering for three years and that's bad even by my standards. Chips with L5 should do a lot to clear that up though.

I have a question for you. If GPS locations in cities are affected by reflections off buildings, wouldn't the effect be deterministic and could you take advantage of that to reduce the noise?

Yes, this is true! If you are interested in working on this kind of thing, please reach out to me via HN messaging.

Re: Super-Accurate GPS Chips Coming to Smartphones in 2018

#184

Post by coderjames »

bb611 wrote: post #142
coderjames wrote: post #119

Earlier quoted context omitted.

Airplanes are already using the higher-accuracy GPS+GNSS to land safely on the runway in low-visibility conditions, guided in by the Flight Management Computer. It makes a big difference whether the plane is 5 meters above the runway or zero meters above the runway.

Commercial airliners use a radar altimeter, not GPS/GNSS to assess altitude. Most if not all airliners equipped with autoland systems use ILS rather than GPS for position as well.

Agreed, but only the big iron. I spent 8 years working for Universal Avionics, who develops precision WAAS-SBAS GPS flight management systems for GA / BizJets: http://uasc.com/home/nextgentechnologies/precisionaviationwi...

Re: Super-Accurate GPS Chips Coming to Smartphones in 2018

#185

Post by lhl »

Deadolus wrote: post #70
lhl wrote: post #34

If anyone works in the field, I'd be interested in how this dual signal (L1/L5) chip interacts with the RTK/CPGPS [1] (which improves accuracy down to 1-3cm already (at the cost of using multiple GPS units)). RTK is commonly used in survey drones, and kits are available for about $1K. [1] https://en.wikipedia.org/wiki/Real_Time_Kinematic

RTK uses a fixed base station, ideally you know exactly where it is so that you know the exact location of your mobile unit (else you will at least get a pretty good relative position). With the new chips, Broadcom, u-blox and others are bringing to market now you are no longer dependend on a base station to get cm-level accuracy. Instead they exploit the different properties of the L1/L5 frequencies to infer stuff a…

I guess my question was more specifically can these be used together for even better accuracy? e.g. if standard RTK on L1 is 1-3cm accurate, and L1/L5 is 30cm accurate, will using two of these new L1/L5 chips in an RTK configuration increase accuracy even more (since they are using different methods of error correction) or are there inherent limits to resolution? Appreciate any insight you might have, thanks.

Re: Super-Accurate GPS Chips Coming to Smartphones in 2018

#186

Post by forapurpose »

brlewis wrote: post #122
forapurpose wrote: post #35

Earlier quoted context omitted.

> accuracy is very bad at times What makes anyone confident in the accuracy of wearable tracking devices? I haven't seen it verified and I wouldn't assume it: Accuracy is expensive, generally speaking, and few consumers will pay for it or even question it - how often have you heard someone mention it? Or, for example, have you wondered how accurate your simple bathroom scale is? I looked into it a little, wanting to…

The > at the end of your sporttechie link is making it 404, but here's the important part: “What the plaintiffs’ attorneys call a “study” is biased, baseless, and nothing more than an attempt to extract a payout from Fitbit. It lacks scientific rigor and is the product of flawed methodology. It was paid for by plaintiffs’ lawyers who are suing Fitbit, and was conducted with a consumer-grade electrocardiogram – not a…

Good point (and sorry for the link, which I'm too late to fix). However, if we take Fitbit's statement at face value, we should infer that Fitbit is as biased and unreliable as the other side, so I wouldn't write off that research.

Re: Super-Accurate GPS Chips Coming to Smartphones in 2018

#187

Post by forapurpose »

jordanthoms wrote: post #41
forapurpose wrote: post #35

Earlier quoted context omitted.

> accuracy is very bad at times What makes anyone confident in the accuracy of wearable tracking devices? I haven't seen it verified and I wouldn't assume it: Accuracy is expensive, generally speaking, and few consumers will pay for it or even question it - how often have you heard someone mention it? Or, for example, have you wondered how accurate your simple bathroom scale is? I looked into it a little, wanting to…

I'm not sure what the value of a more accurate scale would be for a bathroom scale - your weight varies by far more than 100g just based on what you've eaten and how much water you've retained.

> your weight varies by far more than 100g just based on what you've eaten and how much water you've retained.

Yeah, I noticed. Does anyone know how this data is normalized by professional researchers?

Re: Super-Accurate GPS Chips Coming to Smartphones in 2018

#188

Post by lwansbrough »

shpx wrote: post #154
lwansbrough wrote: post #26

I wonder if we'll see these in Microsoft's 2018 HoloLens. 1ft accuracy + spatial mapping = a global spatial mesh with countless commercial applications.

Hololens uses https://en.wikipedia.org/wiki/Photogrammetry which is already more accurate (just watch a demo), so more accurate GPS won't have an effect here. Photogrammetry is what humans do, and it doesn't cost billions of dollars. https://en.wikipedia.org/wiki/Global_Positioning_System#Deve... http://nation.time.com/2012/05/21/how-much-does-gps-cost/

Can a human tell where in the world they are without already knowing something about the environment?

Re: Super-Accurate GPS Chips Coming to Smartphones in 2018

#189

Post by londons_explore »

Crosseye_Jack wrote: post #145
24gttghh wrote: post #140

Earlier quoted context omitted.

Is there not still a limit to GPS accuracy when civilian receivers go beyond a certain speed? e.g. to deter clandestine missile development?

iirc the requirements are an AND condition for speed and altitude. >1,000 knots AND >18,000m. But many civilian receivers implement it as an OR condition much to the annoyance of the near space balloon community. Some will even switch of the radio once one of these limits are reached and not enable it until it's been reset so make them a pain to use for even if you just wanted the location data after your payload com…

Look in the right places and you'll find updated firmware images for various receivers which remove the limits.

That kind of limit is implemented in firmware (all the math is done in software), and they aren't generally protected beyond being an obscure architecture. When you've decided whatever vliw dsp architecture they use, finding a simple 'if' condition near the output logic is quite easy.

Re: Super-Accurate GPS Chips Coming to Smartphones in 2018

#190

Post by Deadolus »

alberto_ol wrote: post #118
Deadolus wrote: post #70

Earlier quoted context omitted.

RTK uses a fixed base station, ideally you know exactly where it is so that you know the exact location of your mobile unit (else you will at least get a pretty good relative position). With the new chips, Broadcom, u-blox and others are bringing to market now you are no longer dependend on a base station to get cm-level accuracy. Instead they exploit the different properties of the L1/L5 frequencies to infer stuff a…

are there already Ublox chips that use the L5 frequency?

Not at the moment.
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