GPS question

Jeff Creamer

Jeff Creamer

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JJC
i have seen an abundance of different gps models. I have not flown a plane with a built in gps, only with an iPad. What is the difference between flying with FF on an iPad vs say a Garmin 430/530? Other than the fact they are built in to the panel and have an included comm.
 
legalities? IFR Certification? Ability to look at your panel vs. your lap? Integration with an autopilot? Durability of design of an iPad vs a panel-mount GPS? Which direction do you want to take this conversation?
 
First. Please. FF is Flight Following. ForeFlight is the iJunk thing some call an EFB.

Differences?

A panel mounted navigator like the 430/530 is certified for IFR navigation.

oops.. @Rgbeard types faster.
 
Legal IFR nav and approach operations. The tablet EFB maps are prettier, but not subject to integrity checks and don't provide vertical guidance and error notifications necessary for safe IFR operations.
 
As above... If you need ifr legal you need a good Garmin.
For VFR I like the ipad and the Garmin 696.
I hate Foreflight! I really like the wing X Pro 7.
 
There is more to flying than following the magenta line. And IFR precision in an approach environment around terrain etc the iPad will not legally give you what a proper 430/530/650 will
 
Jeff Creamer said:
i have seen an abundance of different gps models. I have not flown a plane with a built in gps, only with an iPad. What is the difference between flying with FF on an iPad vs say a Garmin 430/530? Other than the fact they are built in to the panel and have an included comm.
Click to expand...

Something like a Garmin 430W:

1) Will be built from mil/aerospace spec components and be much less susceptible to environmental effects. It's not going to suddenly shut off because it got too hot.
2) Will be hard-wired to the airplane's electrical system, with both battery and alternator power available. No battery dying with no warning because the 12V plug worked its way out of the socket thanks to three hours of vibrations...
3) Will be connected to a CDI (or HSI) right in the pilot's scan that will quickly show how close to the course you are regardless of zoom level.
4) Can detect if any of the GPS satellites are sending slightly erroneous information and ensure the integrity of its position calculation via RAIM.
5) Has had its software extensively quality-checked using methods not normally used in consumer electronics.
6) Calculates its position more often (430W is 5Hz, iPad is 1Hz for example)
7) Is overall going to be much more reliable and much better tested to ensure safety.

That said, they're different tools. A panel-mount IFR GPS is what you use to actually navigate the airplane. An EFB like an iPad with ForeFlight is used for flight planning, situational awareness and electronic charts. Neither is sufficient for all your needs for IFR on its own, but they're for different things.
 
Ouch - guy asks a somewhat naive question and gets kind of slammed. Welcome to POA :).

To the OP - If you are just flying VFR, not a huge difference. Couple of random things, you can pass a flight plan back and forth between Ipad and GPS if they have connectivity. If you have an autopilot, it can follow a GPS course. One other thing is you can divide tasks between devices. For example, keep a map view on the panel GPS and look up your enroute, destination frequencies, runways etc on the ipad.

On the reliability side, tablets can run out of battery and overheat. The certified GPS devices are far more reliable, but not infallible.

If you have plans of flying IFR, then see the comments above.
 
I agree with @pigpenracing - panel mounted, and an aviation specific portable like the 696. Like this:
 

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flyingcheesehead said:
Something like a Garmin 430W:

1) Will be built from mil/aerospace spec components and be much less susceptible to environmental effects. It's not going to suddenly shut off because it got too hot.
2) Will be hard-wired to the airplane's electrical system, with both battery and alternator power available. No battery dying with no warning because the 12V plug worked its way out of the socket thanks to three hours of vibrations...
3) Will be connected to a CDI (or HSI) right in the pilot's scan that will quickly show how close to the course you are regardless of zoom level.
4) Can detect if any of the GPS satellites are sending slightly erroneous information and ensure the integrity of its position calculation via RAIM.
5) Has had its software extensively quality-checked using methods not normally used in consumer electronics.
6) Calculates its position more often (430W is 5Hz, iPad is 1Hz for example)
7) Is overall going to be much more reliable and much better tested to ensure safety.

That said, they're different tools. A panel-mount IFR GPS is what you use to actually navigate the airplane. An EFB like an iPad with ForeFlight is used for flight planning, situational awareness and electronic charts. Neither is sufficient for all your needs for IFR on its own, but they're for different things.
Click to expand...

Not sure the 430 was ever built to milspecs. Training and liaison (VIP) aircraft use them but tactical aircraft use DOD contractor milspec GPSs for P (Y) code and future M-code use. Probably lesser quality than Garmin and with an enormous price hike for the taxpayer. ;)
 
Now to usage. With ForeFlight you follow a magenta line on a moving map. With an installed IFR capable GPS, you tell it what way point/airport, etc that you want to go to and fly following a CDI. Similar to using a VOR needle but you can track to a point that's 1000 miles away.

The other main difference is one is $1000 with $150/ year in subscriptions and the other is $20,000 with $600/year in subscriptions. You have to guess which is which. ;)
 
One is IFR legal and one isn't. One cost considerably more than the other. Both do the basically the same, both will fail when you need them most. That's the short and skinny.

What type of flying are you doing? VFR only I'd go with foreflight. IFR. .panel mount and foreflight. Makes life a bit easier.
 
Velocity173 said:
Not sure the 430 was ever built to milspecs. Training and liaison (VIP) aircraft use them but tactical aircraft use DOD contractor milspec GPSs for P (Y) code and future M-code use. Probably lesser quality than Garmin and with an enormous price hike for the taxpayer. ;)
Click to expand...

Not the device, the electronic components... That just means they were designed to operate correctly at temperatures between -55ºC and 125ºC, among other things. It's one reason the 430 will never say "Too Hot - Please cool your device." ;)
 
flyingcheesehead said:
Not the device, the electronic components... That just means they were designed to operate correctly at temperatures between -55ºC and 125ºC, among other things. It's one reason the 430 will never say "Too Hot - Please cool your device." ;)
Click to expand...

Yeah but will it survive a nuclear detonation? :biggrin:
 
The biggest difference is the certified units are capable of knowing and telling you when they're not accurate. The tablet device is not. And this happens more often than you would think.

VFR flight on a nice CAVU day? Doesn't matter whole lot if you're still situational aware with a chart (I don't care whether it's paper or not). As in, I'm looking at the chart regardless of where the app says my plane is and asking things like "Is that lake/airport/terrain feature where I think it should be?"

IFR flight in IMC? I want the GPS that can tell me things like "Vertical Guidance compromised" (or whatever verbiage they use). Certified units have to have RAIM (as mentioned above). Look it up and understand it.

There's a variety of reasons the certified units cost so much more. Some is volume and the aviation "because we can" surcharge. But some is added functionality for real, no kidding safety.

John
 
If you're VFR only you have a LOT of options for non certified GPS. Non cert units can be more up to date and even state of the art as opposed to an IFR GPS due to extra requirements for any changes to a certified unit. A good, dedicated portable such as an IFLY 740 is easier to operate and provides things like weather and traffic with a cheap ADSB in, that can't be done on a cert unit without greatly added expense. Chart updates are significantly cheaper also. Be a bit careful if you're solely relying on a tablet app as they can be more glitchy, such as losing wifi, losing GPS, locking up, overheating, etc.
 
eman1200 said:
who slammed? I don't see any slamming....
Click to expand...
And rgbeard. Read it at the end of a crappy work day. Might have over thought it. Guess I was reacting to all the “no good for IFR” comments. My guess was someone flying IFR wouldn’t be asking. Any rate it was a truly crappy day
 
Hang 4 said:
And rgbeard. Read it at the end of a crappy work day. Might have over thought it. Guess I was reacting to all the “no good for IFR” comments. My guess was someone flying IFR wouldn’t be asking. Any rate it was a truly crappy day
Click to expand...

sorry to hear that. if this was the good ol' days of PoA I'd post a booby pic to try to cheer u up.
 
I remember my first GPS. A hand held unit that only showed an arrow pointing towards the destination, which the user had to plug in lat and longs for the destination. It was made for hikers.

Then a few months later I saw one that actually had a count down timer showing time to destination... and the race was on.

The latest new GPS I saw gives a person a reminder to go to the bathroom, even if you don't think you need to go......
 
Half Fast said:
All true, but you can get RAIM in ForeFlight:
https://foreflight.com/support/video-library/watch/?v=raim-prediction-in-navlog
Click to expand...

RAIM prediction is not RAIM. RAIM prediction tells you if there will be enough satellites in view for the receiver to perform RAIM, it needs more than the base 4 in order to be able to verify the position/velocity/time solution and RAIM prediction uses the published orbit parameters along with your flight route to see if the needed satellites will be in view. It's almost certain that the on-board iPad GPS doesn't provide the needed raw pseudorange data for an app running on the iPad to do RAIM, obviously a bluetooth or WiFi GPS device could.

And with WAAS it's needed much less frequently as the WAAS satellite provides status on all the other satellites in the constellation. It's only when WAAS data itself goes away that we need RAIM again.
 
Don't forget. IFR rated units need a panel mounted annuciator to let you know when its in approach mode. The scale on the CDI changes. Garmin 530.
 
Maxnr said:
Don't forget. IFR rated units need a panel mounted annuciator to let you know when its in approach mode. The scale on the CDI changes. Garmin 530.
Click to expand...

That's so very 37 seconds ago...

They don't all need a separate annunciator anymore.
 
Maxnr said:
Don't forget. IFR rated units need a panel mounted annuciator to let you know when its in approach mode. The scale on the CDI changes. Garmin 530.
Click to expand...

pburger said:
That's so very 37 seconds ago...

They don't all need a separate annunciator anymore.
Click to expand...

I thought the Garmin 530 was a weird example, because it didn't need the separate annunciator either (as long as it was close enough to the pilot's field of vision).
 
Challenged said:
How do the dual frequency GPS chips popping up in phones/tablets now compare to the certified stuff? https://medium.com/@sjbarbeau/dual-frequency-gnss-on-android-devices-152b8826e1c
Click to expand...

Near term, I'd rather have carrier phase chips, since the dual freq constellation is still being built. Longer term, dual freq will bring some nice second-order effects (better ionospheric delay measurements, better radio occultation) in addition to improved position accuracy.

Does anyone know if chipsets that support GLONASS will work during GPS interference testing?
 
Thanks George. I've asked the GLONASS question myself a couple of times here without response (that I recall). As my phone supports GLONASS, I'd be curious to know this.
 
Ravioli said:
First. Please. FF is Flight Following. ForeFlight is the iJunk thing some call an EFB.

Differences?

A panel mounted navigator like the 430/530 is certified for IFR navigation.

oops.. @Rgbeard types faster.
Click to expand...

A few more years and mentioning FF without explanation will pretty much guarantee the iJunk recognition among 90% of pilots.
You may not like it but you can’t change it ...
 
Using a panel mount and FF together: the Garmin series (and most panel mounts) have a crappy user interface. FF on an iPad has a more intuitive interface, so changes are quicker and easier to do on FF (or Garmin Pilot) on your tablet. Add in a bluetooth connection between your panel mount and your iPad (an FS210), and they can pass data to each other, like flight plans, traffic, weather, etc.). Your iPad becomes a display extension and control head for your panel mount.

To your question; they're more alike than diffrent. Both are software driven and so will, at some point, try to kill you. Others have mentioned the greater reliabilty and exponentially higher costs of the panel mounts. VFR only, I'd go with FF on an iPad with an external GPS receiver, like a Dual or Bad Elf.
 
Rgbeard said:
My question at this point goes to the OP.

Did you get an answer to your question?
If so, what direction were you trying to go?
If not, what are you looking for?
Click to expand...
In short, yes, I got an answer. In retrospect, I would have asked in a little different manner. I am a student pilot that is nearing check ride time. I’ve never flown in a plane with a panel mount GPS and after using Fore Flight (be sure to spell it out - FF means flight following ) it seemed confusing as to why you would want to invest $10-30k for equipment that did basically the same thing. It honestly didn’t occur to me that to be an IR pilot you needed that equipment nor that it was that much more precise. I appreciate all the input.
 
Jeff Creamer said:
It honestly didn’t occur to me that to be an IR pilot you needed that equipment nor that it was that much more precise. I appreciate all the input.
Click to expand...

Technically, you don't "need" an IFR GPS in your panel to fly IFR, but you have to do it the old way that IFR was done before GPS was invented, which mostly involves flying on Victor airways. Being able to fly direct and make use of GPS approaches is a big help.
 
GeorgeC said:
Does anyone know if chipsets that support GLONASS will work during GPS interference testing?
Click to expand...

It depends. From an RF perspective, the frequencies are different, but it would depend on the interference. Relatively wide-band interference would affect both. Narrow band interference, designed solely to kill GPS, for example, would theoretically not affect GLONASS.

I would suspect that the chipsets (and more importantly, the supervisory software that crunches the data) would be able to continue using GLONASS if GPS became noisy. But that's a guess. I'm told that typical software compares the two to come up with better accuracy. Who knows the effect if, say, GLONASS is right, but GPS is providing gibberish? You'd have to ask the vendor on a specific model, and they might or might not even answer.
 
Stephen Poole said:
It depends. From an RF perspective, the frequencies are different, but it would depend on the interference. Relatively wide-band interference would affect both. Narrow band interference, designed solely to kill GPS, for example, would theoretically not affect GLONASS.

I would suspect that the chipsets (and more importantly, the supervisory software that crunches the data) would be able to continue using GLONASS if GPS became noisy. But that's a guess. I'm told that typical software compares the two to come up with better accuracy. Who knows the effect if, say, GLONASS is right, but GPS is providing gibberish? You'd have to ask the vendor on a specific model, and they might or might not even answer.
Click to expand...

And just reading this (admittedly after only half a cup of coffee) makes me ponder how (as a software engineer) I'd try to establish which is more accurate? All seriously fault tolerant computer systems I'm familiar with have 3 (or more) sources and do a majority vote. With only two you know somethings off, but how do you decide which? Save last position at shutdown and compare? Suppose the unit (plane, portable, whatever) moved with the gear shut down? If one is in fact utter gibberish (we're now somewhere off the space body formerly known as a planet a.k.a. Pluto OK, that's gibberish) I suppose you could. Hmmm. More coffee.

It is important to remember that these RF signals are very, very weak. They are easy to completely overwhelm.

John
 
With two inputs , the only I can think of , would be to maintain some kind of trend representation ( based on historical data) and then , if the sources disagree, measure deviation from the trend and go with the less dramatic input ...
 
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