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Garmin Oregon 450t GPS Chipset


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Personally, I think the new chipsets are as good as the old SiRFstar III. I wrote about it recently at...

http://gpstracklog.com/2010/02/getting-ove...rfstar-iii.html

 

Scroll down to the end in my Oregon 450 review and you'll see I got a cleaner tracklog with it than with the 60CSx...

 

http://gpstracklog.com/2010/04/garmin-oregon-450-review.html

 

Also, for anyone who's interested, the manufacturer appears to have made changes in the SiRFstar III, so the chips in the Magellan eXplorist GC are probably not the same as the original SiRF III.

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Personally, I think the new chipsets are as good as the old SiRFstar III. I wrote about it recently at...

http://gpstracklog.com/2010/02/getting-ove...rfstar-iii.html

 

Scroll down to the end in my Oregon 450 review and you'll see I got a cleaner tracklog with it than with the 60CSx...

 

http://gpstracklog.com/2010/04/garmin-oregon-450-review.html

 

Also, for anyone who's interested, the manufacturer appears to have made changes in the SiRFstar III, so the chips in the Magellan eXplorist GC are probably not the same as the original SiRF III.

Are you sure that they haven't already begun to use the SiRF IV chips? I haven't looked into Magellan's specific chip, but the IV is the hot new item from our friends at Cambridge Silicon.

 

As for the tracks - and I shudder to consider that we're both dealing with samples of one - I've found that the Mediatek chip in my Summit HC settles to a lower EPE much more quickly than the Cartesio in my Dakota 20. That isn't just the firmware deciding what to call the EPE, either, which as we know can be pretty abitrary. My Summit drops to a total drift of 0.001 almost immediately in clear sky. My Dakota does not. It seems to take a full minute or so longer to become truly stable. Still doing the homework on the comparo test, but so far, the results have been pretty consistent. Then again, with the jump to chip firmware 4.25, I'll probably have to start the test from scratch since we have no REAL idea what they did under the hood. I'm never impressed with Garmin's vague release notes on the chip itself ;)

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first to know: there is more then only one chipset named "SiRF III", it's a family of chips since a couple of years now. the actual model is still called SiRF III and scans 64 channels.

SiRF IV is more expensive and mostly used in some later car navigation units but was designd to use in cellphones.

Mostly called "SiRF IV" is in some advertisements not the gpsr-chip, there is a system controller with the name "SiRF Atlas IV" (contains a SiRF3-Decoder) and Navigon for example say, their mobile units contain a "SiRF IV chip". But it's not the "SiRFstar IV", it's the Atlas SOC-Controller. (System on a Chip = SOC, a CPU, memory and peripheral controllers on one chip).

 

By the way, GALILEO, the european navigation system is far away from a usable status. Took more then 5 years to go, this might be a point for a future "SiRFstar VI".

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first to know: there is more then only one chipset named "SiRF III", it's a family of chips since a couple of years now. the actual model is still called SiRF III and scans 64 channels.
The GSD3 and GSC3 series chips are all 20 channels, max. So while I keep hearing about these SiRF III chips that supposedly manage 64 channels, I've still not seen a part number / spec sheet that says just what that chip might be.

 

SiRF IV is more expensive and mostly used in some later car navigation units but was designd to use in cellphones.
Not sure why they'd put them into automotive use, but the lower power that they require makes them a better bet for cell phones.

 

Mostly called "SiRF IV" is in some advertisements not the gpsr-chip, there is a system controller with the name "SiRF Atlas IV" (contains a SiRF3-Decoder) and Navigon for example say, their mobile units contain a "SiRF IV chip". But it's not the "SiRFstar IV", it's the Atlas SOC-Controller. (System on a Chip = SOC, a CPU, memory and peripheral controllers on one chip).
Remains to be seen if Garmin opts for the SOC or just the GPS portion ... or none of the above.

 

By the way, GALILEO, the european navigation system is far away from a usable status. Took more then 5 years to go, this might be a point for a future "SiRFstar VI".
Is as I noted in a different thread nearby earlier today (http://forums.Groundspeak.com/GC/index.php?showtopic=247520). I also don't think that the GLONASS system provides the full HP signal except for their own military applications - at least I never heard that they opened it up. So for the time being, we're the only game in town for geocaching... Edited by ecanderson
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GLONASS uses a different frequency than GPS.

You can buy receivers, but best usage is in central asia where the most satellites are located. The few recivers that uses GLONASS are not for such a mass market than GPS receivers are, so they are way more expensive.

 

With such a dual-receiver you get around 10 GPS-signals and additional 4 GLONASS-signals wich brings you to an accuracy of below one meter in most cases.

 

Example link to existing product:

http://www.inovagis.com/gbr/gps-receiver.htm

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Personally, I think the new chipsets are as good as the old SiRFstar III. I wrote about it recently at...

http://gpstracklog.com/2010/02/getting-ove...rfstar-iii.html

 

Scroll down to the end in my Oregon 450 review and you'll see I got a cleaner tracklog with it than with the 60CSx...

 

http://gpstracklog.com/2010/04/garmin-oregon-450-review.html

 

Also, for anyone who's interested, the manufacturer appears to have made changes in the SiRFstar III, so the chips in the Magellan eXplorist GC are probably not the same as the original SiRF III.

While I agree with you that the SiRF III is a bit dated and will happily purchase a receiver that doesn't have it (in fact will avoid receivers that use it nowadays...), I disagree that the Oregon's chipset isn't in need of replacement.

 

The STM Cartesio is notorious for absolutely poor WAAS performance. It's just plain awful - in both receivers that use it (Oregon and PN-40), it's extremely rare for anyone to have a WAAS lock.

 

However, Garmin has signed a deal with MediaTek to use their chipset in yet-unnamed receivers - I had some hope that the 450 was MTK v2 based. I have an MTKv2-based Bluetooth puck and its performance is incredible. It locks fast, locks WAAS instantly, and usually locks lots of satellites at high SNRs.

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