Using a Car GPS for Flight Navigation

[dov_elyada]

I fly an ultralight. Typical altitudes are 500' AGL and navigation is by landmarks. Where I can't recognize the landmarks, or where distinct landmarks do not exist or are far-between, I switch to using uncorrected compass bearings -- good enough, considering the relatively short legs and the mild-wind days I select for flying.

Recently I installed in my plane a car GPS device (QUE NQ-503) running a cross-country land navigation software. (After all, the difference between 500' AGL and an SUV's 5' AGL is not all that big.) The software is basically a moving 1:50,000 topographic map on which one can add routes and labeled waypoints. To navigate, all one has to do is keep the GPS position marker on the prepared route. Can't ask for anything more.

For about 10 flight hrs this device performed just fine. Then hardware problems set in which gradually made it useless. I suspect the reason lies in the harsh acoustic and vibrational environment (unbearable without a headset on) that exists on the dashboard where the device has been installed. Indeed, when I moved it back to my car the problems went away.

My questions:

1. Anyone out there with a similar experience?
2. Any suggestions as to how to protect the device from the environment?
3. Are aviation GPS devices guaranteed to withstand an ultralight cockpit
acoustic and vibrational environment?
4. What kind of backup people use in case the GPS malfunctions (apart from
radio homing)?
5. Anything else that might be helpful in this respect.

Thanks for the advice

[Joe LaMantia]

Well I've never tried a car GPS in an airplane, but I have used a few handheld aviation GPS's and they can and do loose signals from time to time. In my experience with lost signals I find that high-wing airplanes tend to experience that circumstance more often then low-wing. It may be due to a smaller overhead view available in the high wing cockpit vs a low wing design. I have been trying to get a Garmin Pilot III working in our club TriPacer for the past few weeks. It was setup with just a simple top panel mount and the standard "stick" antenna when it did work it was hard to read and harder still to operate while flying. I bought an extended antenna and replaced dead batteries and the unit works fine in my car, but I've only been able to get it into Navigation mode once in the airplane. I have moved antenna locations all over the cockpit trying to get a good view without much luck. I'm going to try it in our club Archer (low-wing) next week and see if that is any better.

I don't know much about ultra-lights but I always plan flights using charts and ground based radio aids even when flying with very reliable panel GPS installations. I'm guessing that flying an ultralight is mostly flying within 50 miles or less of your base airport where navigation is primarily "looking out the window" and finding local landmarks. If your just starting out I would plan to fly a lot of local or short flights around your base and then just expand your circle as you get familiar with the landmarks.

Joe
:cool:

[Racegunz]

There are great... well maybe good deals on used aviation gps out there, I have 3, a garmin pilot III, which is good and something must be wrong with your cause mine has been dandy, I have 2 Lowrance's a 600c (my favorite) and a 1000 (newest addition) that I haven't flown with yet, an external antenna is a must and I see no problem with using a topographical gps in an ultralite or in anyplane, just never, ever rely on them as primary navigation, get the charts out and plan the trip like you have nothing but a compass, it's a skill that requires practice but will save your bacon and give you confidence. As for yours not handling the vibration well such is the way of modern electronics, probably a cold solder joint and the vibration finally took its toll.

[rwanttaja]

What kind of hardware problems did you experience? Loss of GPS signal, loss of display, power loss, etc.

I doubt the acoustic environment is to blame, but any problems could indeed be due to vibration. My thought is that you have the unit solidly attached to the structure and the engine is causing the problem. Is the problem affected by engine RPM? (e.g., does it stop when the engine is throttled back to idle, does it get worse on full power, is there a particular RPM range where it's worse, etc.)

If you've got the unit clamped using the same sort of unit as in a car, the vibration in the structure could be getting transmitted directly to the GPS. You need some isolation....some rubber or foam between the mount and the structure.

I've had vibration problems messing up videos on my airplane, and have cut it back by using such isolation materials. Here's an old shot of a camera mount clamped to the axle. There's a wide strip of inner-tube rubber between the mount and the axle.
1766
The materials are cheap, so experimentation is easy.

I have a hiking GPS in my Fly Baby, but haven't had any vibration-related problems with it. However, it is mounted on an arm that comes up a few inches from the mounting point... this gives a bit of flexibility as well, which probably isolates it.
1767

Ron Wanttaja

[maddogmorgan]

These is http://www.oziexplorer.com/ poplular with the Ultra-lights in Oz, you can put digital charts straight in as well, use a windows CE based car GPS.

[dov_elyada]

Thanks, Joe.The problems I was complainng about are not of the missing-signals type. This GPS device has only an internal antenna and when it misses too many satelites it just displays a message saying so.As for my range of operations--you may be surprised to learn that this plane (ICP Savannah) at cruise IAS (80 mph) can fly 5 hrs and 400 miles w/o refueling. I never tried it to the limit, and I do not intend to, but 3-hrs continuous flight is standard. Actually, it's an ultralight in some respects (1000 lb MTOW, flimsy construction, taking in rain, no nav aids or transponder, no IFR instumentation whatsoever, true STOL and "bush" performance) and an LSA in other respects (two-seater, 100HP Rotax 912 ULS, Vne=125 mph, 1100 fpm max climb rate.) I have decided I need a GPS as my main navigation method, keeping the chart and compass method as a backup, once I have started long-distance flights accross wilderness areas.

[dov_elyada]

Thanks, Racegunz

As I said, what I was using is just my car GPS (neither a Garmin nor any other aviation brand) transplanted to my airplane.

I agree with you that plain old chart and compass navigation is a necessary skill, and I do have it, but it's so boring to prepare and then not use. Another problem with this kind of "office flying" is that I do not really have enough "desk space" on my lap to fold, unfold, shuffle and browse through all those papers; they tend to interfere with the stick and block the view of the flight gauges. I did make a special knee-pad (better than anything you can buy at Sporty's) to deal with this hassle, but with so little space it is still a big hassle.

And one more thing: Flying at 200'-500' AGL you cannot afford to take your eyes off the outside for any appreciable length of time -- you might suddenly find yourself approaching a high voltage power line or a cellular antenna tower, or an uphill slope or a powerful windshear. And where's the fun of flying when you have to wrestle with the papers instead of enjoying the views?

When I asked the forum what kind of backup people use, I was hoping to hear that some were using a 2nd GPS. That's my tendency.

[dov_elyada]

Thanks, Ron.

There occurred a variety of hardware-looking problems, non of them was related to loss of GPS signal. Examples: (1) The moving map and GPS position marker froze and the on/off button did not respond; since I couldn't use the reset button in flight, I yanked the supply cable out and waited until the battery was used up. (2) The map stopped moving and gradually the GPS position marker went out of the frame. (3) Recurring crashes: suddenly the navigation software would go off and restarting it would keep it going for only a minute or so before the next crash.

When installing the GPS on the dashboard I did pay attention to vibration isolation. The dashboard itself is padded with foam and vinyl upholstery and the spring clip pressing the base of the pedestal to it is doing so through a thick and soft rubber cushion. That's why acoustic noise was my most likely culprit. Yet the possibility still exists that what I've done to isolate vibrations is not sufficient.

[dov_elyada]

Thanks.

That's roughly what I have, though up-over rather than down-under. So if anyone experienced similar problems, it's probably those Aussies.

[rosiejerryrosie]

I used to use a simple Garmin 100 (cost at Kmart=$100) in my MiniMax. Worked fine, once I got all the airports and waypoints manually entered, until, one day, it just went dead on me. On landing, it worked fine. After that happened two more times, I contacted Garmin and they recommended that I use ALL the same type of batteries in my unit ie don't mix Everready with Duracell for example. Once I did that - never had another problem. Vibration was not the problem since the unit was NOT mounted to the airplane but suspended from my wrist on a lanyard. Subsequently, I now use a Garmin 196 in my Aeronca, but Judy likes to take along the Garmin Nuvi from the car, because it shows her all the roads that we are crossing over, and she feels more 'oreinted'. It is not mounted either as she holds in in her lap - so vibration is not an issue. Works fine. If your unit is 'freezing' it sounds like it is losing signal for some reason and is not able to update your position as you move..... Antenna?

[rwanttaja]

Thanks, Ron.

There occurred a variety of hardware-looking problems, non of them was related to loss of GPS signal. Examples: (1) The moving map and GPS position marker froze and the on/off button did not respond; since I couldn't use the reset button in flight, I yanked the supply cable out and waited until the battery was used up. (2) The map stopped moving and gradually the GPS position marker went out of the frame. (3) Recurring crashes: suddenly the navigation software would go off and restarting it would keep it going for only a minute or so before the next crash.

When installing the GPS on the dashboard I did pay attention to vibration isolation. The dashboard itself is padded with foam and vinyl upholstery and the spring clip pressing the base of the pedestal to it is doing so through a thick and soft rubber cushion. That's why acoustic noise was my most likely culprit. Yet the possibility still exists that what I've done to isolate vibrations is not sufficient.
With that info, I'm inclined to think the problem might be a faulty unit rather than environmental. Is it still under warranty? Have you checked whether there's a firmware update available? Vibration-related hardware issues are probably going to cause complete failures, not weirdness like the map stopping moving while the unit continues to update position.

Another possibility is that the unit is having problems with EMI/ESD (electro-magnetic interference/electro-static discharge) or the supply voltage. For EMI/ESD, you want to make sure any external metal (such as antenna ports) are covered. However, the touch screen itself can be the main point of vulnerability. Here's a writeup from a company that does OEM shielding... it explains the problem:

http://www.bergquistcompany.com/pdfs/techLibrary/Touch_Shielding.pdf

That company's product can only be applied during manufacture, so it's no help to you. ESD would actually explain the fact that the unit worked fine for the first ten hours; the built-in countermeasures worked fine until a microscopic hole got punched through by a bigger-than-normal discharge. It then became vulnerable to lower-level shocks.

You *might* try applying a screen protector such as is sold for IPADs and smart phones. I'm not too optimistic, since the ESD entry route appears to be the edges, not the glass itself.

Another factor that might be an issue is electrical noise via the power line. Assuming you've got an engine with an alternator, this shouldn't be an issue...but if you're using one of the Rotax versions that get power from the magneto, it might be a bit more likely. This is easy enough to eliminate... charge the GPS's internal batteries, and make a flight or two and see if the problem goes away. If it does, then additional power line isolation will help.

Ron Wanttaja

[Cap'n Jack]

I've used a Garmin V for years for this purpose on faster planes (PA-180, C172, etc). I used to download the XL data files from the FAA, but this site:
http://navaid.com/GPX/
has the data in GPX format (nav aids, airports, etc). The Garmin software (Mapsource) reads this readily, albeit slowly, and I just upload the area I want into the GPS as waypoints. I suspect the sucessor to Mapsource, Basecamp, works as well; I just downloaded it and haven't tried it yet.

I have a Garmin Nüvi too. It's a very capable car GPS and works in airliners, but doesn't allow access to the track (I use the track for geo-tagging photos; my phone didn't have the limitation). I suspect it's a speed limit thing- the track is saved and visible, but that part isn't in the track file. In an ultralight, I think you'd be well below the cutoff speed in the GPS (whatever it is) but it is something to be aware of. Test it well before leaving your local area.

As suggested earlier, the GPS is only a part of my navigation portfolio. I use charts, VORs, and deduced reckoning too.

[FrankCordrey]

I use an Adventure Pilot iFLY 700 in my Cessna 150. Although it is not an ultralight, it is pretty limited on panel space.

An aspect you may find very helpful is the availability of an external antenna. I have the GPS fixed to the yoke which puts it well down inside the all metal aircraft. I do not have the external antenna but I have never lost GPS signals nor ever gotten a warning due to weak signals. There are several methods available for mounting so the positioning and vibration issues should be easy to resolve. Map updates are very reasonable as well.

Check it out at http://ifly.adventurepilot.com/HOME.aspx . No, I do not work for the company. It is a good unit that works well and is more affordable than many alternatives I had to choose from. I just thougth I would share the help.

I will sell you my 700 ( 5 months old ) because I am upgrading mine to the newer 720 model. This will help you keep the cost down.

Check it out. If you like it then give a reply.

Frank

[dov_elyada]

Thanks, Jerry

The batteries in my unit are built-in and can only be replaced in a lab. Also, the antenna is internal and there's isn't even an external antenna socket. In case not enough satelites are seen, e.g., inside the hangar, the unit doesn't freeze--it displays a message "No Satelite Reception," but the map can still be moved around and all non-GPS functions still work. That wasn't the case when one of those problems I described popped up.

One more attempt before I give up this device for flying is doing what you said: remove it from the dashboard and strap it to my arm or lap. It isn't very convenient, though, and it might reduce the freedom of operating the controls.

[Jetblast18]

Not sure what kind of phone that you have but this works pretty good as a back-up. Mounting so that you don't lose it...well that's another story. http://inavigator.leosh.com/Home.html

[avinuts]

First unit that I purchased was as an experiment to see if I could use a handheld unit designed for the outdoors type person (hunting, backpacking)as a backup to the aircraft equipment. It had all kinds of problems in the aircraft. I contacted the manufacturer who routed me to an engineer. They stated that under no circumstances is a handheld GPS recommended by thier company for use in an aircraft. That said (to cover thier butt), I asked a few hypothetical questions. It seems that you need to look at how often or fast the unit reads the signal from a satlite. Speed and distance then play a part in the equation. If your ground spead is too fast for the unit, by the time it reads where you are at, you are now someplace else, it becomes confused, tired and frustrated, so eventually "gives up" trying to read the signal.

[dov_elyada]

Thanks, Avinuts
That's why I don't have the audacity to claim a faulty unit replacement from the supplier, because I clearly use it outside of its intended envelope. Anyway, the fact that I was successfully using it for many flight hours before it began to give me trouble tells me the device's performance limitations are not the issue. By the way, at 80 mph--my normal cruising speed--cars on the freeway do pass me.

[cluttonfred]

Another option you might consider, the Gipsi voice-based GPS, no screen, just a synthesized voice in your headset when you want it, keeps your eyes up and scanning instead of down in the cockpit. I wrote the article below but have no connection to the manufacturer other than thinking it's a neat product.

A Gipsi for your FRED? (http://cluttonfred.info/post/13352767261/a-gipsi-for-your-fred)
www.gipsinavigation.com (http://www.gipsinavigation.com/)

[Dana]

I've been using a Garmin handheld GPS (60Csx) for flying for several years now. It works quite well, and even has a "glide angle" display aimed at the hang glider market. I put an airport database into it, and even rudimentary airspace.

I understand that some Magellan units have a 100 mph limitation, though.

[Cap'n Jack]

I've been using a Garmin handheld GPS (60Csx) for flying for several years now. It works quite well, and even has a "glide angle" display aimed at the hang glider market. I put an airport database into it, and even rudimentary airspace.

I understand that some Magellan units have a 100 mph limitation, though.I have a recent Garmin Nüvi that seems to have a speed limit with respect to saving tracks. I used it on a jet- I could see the track on the unit but I couldn't down load it. The screen updated correctly. I don't know what the lower speed limit for recording tracks, but an ultralight at 80 MPH should be fine. This is one reason I keep my Garmin V- works fine at all speeds.

[martinez777]

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[Frankrv6]

If you have an Andriod based phone or tablet that has built in gps antenna download Avare and yo will have a great inexpensive gps that is for aviators.