GPS at Aldi this week $179

[Simmo67 Senior Member Find all posts View Profile Close Simmo67]

I noticed Aldi Supermarkets have a "Tevion" brand GPS on sale next week from Thursday 10/04/08 for $179 8)

It's features include
3.5" touch screen
400 MHz speed
512MB built-in memeory
Atlas 3 CPU
Navteq Mapping Version 7
Speed camera and red light camera warning
Photo viewer
Includes car charger, windscreen mount, USB cable and stylus
Position accuracy under 10m
MP3/MPEG4 function



http://www.aldi.com.au/au/html/offers/2827_4798.htm

Can anyone tell me if this unit would be a good buy or would I be disappointed?? I had a TomTom program for a while on my PDA (powered by Whereis) and it was good but died on me. It seemed easier to use/better than the Garmin Navigators we have at work.

Any feedback appreciated. In particular I am wondering if Navteq maps are as extensive/detailed as Whereis maps - particularly in regional areas??

[Spurio Senior Member Find all posts View Profile Close Spurio]

Some GPS info

You get what you pay for, there maybe possible issues using different or updateable software in cheaper units. Or they may charge big bucks to do a software update.

I am an anally retentive spurious error searcher, that knows way to much about mapping and finds errors that other people (the misses) don't care about. So take this with a grain of salt....

The US military set the SA or Selctive Availability (accuracy) of all civilian readers and it is not 10 metres. No C/A chipped unit is more accurate than 100 metres 95% of the time (calculating error correction). In basic english this is averaged out to vary between 10-20metres in real on ground terms (this is not including the calc to correct for estimated error probability). THIS ACCURACY IS MORE THAN ENOUGH FOR MOST CIVILIAN USES.

If you want greater accuracy you can get into Differential GPS units (start from about $10K up) which correct the error down to 5-10m.

I have found the whereis dataset not that accurate when you leave the main tracks within 2 or so hours of a city.

Here is a whole bunch of boring info:

There are two basic inbuilt random errors in a C/A coded GPS, they are:
CEP (circular error probable) which apply to horizontal accuracy only.
SEP (Spherical Error Probable) which apply to combined horizontal and vertical accuracy.

Combined they create a "strain ellipsoid", which is kind of like an elongated sphere but longest on the z axis (altitude axis) in the case of a GPS. This is a dynamic sphere constantly adjusting in dimension for each point.

Vertical accuracy (altitude) is absolutely useless. Think about what a GPS could be implemented into if you were a very bad person, then you know why they retard this feature.

Accuracy is calculated on the percentage of times a registered position falls in relation to the radius centre of truth, within the strain ellipsoid at that point in time. Its is expressed in root-square-mean (RMS)

The sad thing is many people are using the wrong datum and do not get the correct projection/reading anyway. i.e. GDA94 is the most correct in UTM projection, AGD84 or 66 or WGS is old technology.

I use a magellan

If I didn't have a GPS unit and for $180 I would buy one and throw it away and buy another if it breaks. This is still cheaper than getting a decent brand model.

[mav Addicted PP Member Find all posts View Profile Close mav]

Re: GPS at Aldi this week $179

. In particular I am wondering if Navteq maps are as extensive/detailed as Whereis maps - particularly in regional areas??

G'Day Simmo, mate Navteq mapping is the worst I have found for regional and metropolitan areas. I never thought I would say this but Sensis maps are now the best for Australia as although all the mapping companies have errors Sensis seems to have the least from my experience.

[Simmo67 Senior Member Find all posts View Profile Close Simmo67]

thanks for the feedback there fellas....

I was wondering about that mav; living in the country I am looking for something with good overall detail - not just Pitt Street Sydney. (I just visited that website you recommended in a previous thread mtekk.com.au and yeah they reckon Senis beats Navteq).

And looking at the Aldi unit further i want to stear away from the big bracket thingie - prefer the all in one units around.

I see TomTom has recently brought out 08 Australia maps. I might do some more research on those too.

Anyway appreciate your feedback and advice guys..