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Epic has different GPS chip from Galaxy S GSM devices!?

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By boomerbubba, Senior Member on 15th October 2010, 10:20 PM
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Just looked at a teardown report of the Epic 4G (hat tip to los1223). It appears that the Epic 4G does not even use the same GPS chip as its GSM cousins. This is certainly news to me, because reading the tea leaves I have assumed that all Galaxy S phones shared the same GPS hardware, even if the software was in different stages of development and debugging.

According to the teardown, the Epic 4g uses the multifunction Qualcomm QSC6085 for GPS functions. (Presumably this is because of the CDMA radio, so the Fascinate design is probably similar.) Previous analysis the GSM variants, based on the international I9000 model as well as the Captivate and the Vibrant, showed they use a Broadcom BCM4751 chip.

This would explain why the symptoms of the GPS problems on the Epic, and the firmware modules, are not the same as those on the GSM variants. But amazingly, it seems that Samsung managed to screw up two different GPS designs in two different ways.
16th October 2010, 05:35 PM |#2  
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Is one chip better than the other?

I know my co-worker's TMobile Galaxy S (Captivate, Fascinate, Masticate...whatever) just recently received the GPS update and he states it is now spot on and very quick to lock.

Didn't ask about any hard coded location, though, like ours. I'll have to do that on Monday.
16th October 2010, 06:31 PM |#3  
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Thats ame gps as the motorola droids use I think



The new QSC6085 features include:

Support for EV-DO Rev. A with backward compatibility to EV-DO Rel. 0 and CDMA2000
Equalizer technology for increased EV-DO data throughput
Powerful GPS location capabilities, including gpsOne(R) multi-mode hybrid assisted GPS technology, enabling a broad variety of location services such as navigation, social, safety and security applications
Up to 3 megapixel camera support with anti-shake capability
15 fps video encode and decode capability
72-voice polyphonic ringtones with support for multiple audio codecs
Multiple technologies to improve network capacity, including QUALCOMM Linear Interference Cancellation (QLIC(TM)) with pilot and traffic cancellation, and Fourth Generation Vocoder(TM) (4GV(TM)), published as the EVRC-B 3GPP2 standard codec, which gives network operators the flexibility to prioritize voice quality or network capacity
Support for multiple bands, including 800 Mhz, 1900 Mhz and the AWS band (1700/2100 Mhz), with mobile receive diversity
Cost-effective 65 nm process technology and a 12 mm x 12 mm package size
16th October 2010, 11:45 PM |#4  
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Quote:
Originally Posted by othan1

Is one chip better than the other?

Let me first lead off by same I'm not an expert on chipsets. That being said, I did a lot of research on the QSC6085 when I was looking to see if it supported TV out or if we were never going to have that feature (I can honestly tell you that I don't know enough about this stuff for a conclusive answer, but right now I'm guessing no for the 3.5mm port).

Anyhow, the QSC6085 is an integrated processor that does a lot of this with one chip rather than having multiple chips that do many individual things. The purpose was to reduce costs and potentially, create power savings as well.

The other galaxy S phones (at the least the GSM ones) have a dedicated GPS chip to where the Epic's/Fascinate's baseband modem (QSC6085) handles all kinds of things, including GPS.

Other devices that use the QSC6085 (like the Droid, Droid 2 and my Sierra Wireless modem) do not seem to have the same GPS problems as the Epic/Fascinate which tells me it's a Samsung implementation issue and not a problem with the chip.
16th October 2010, 11:48 PM |#5  
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It's either the software (highly likely, no reason for us to not get a fix within seconds even if it is horribly inaccurate) or an insensitive GPS antenna. The GPS antenna is easily spottable on the Vibrant and Fascinate. It's covered by black tape next to the SD card on the Fascinate, it should be the same on the Epic 4G.
17th October 2010, 09:44 PM |#6  
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Quote:
Originally Posted by heygrl

It's either the software (highly likely, no reason for us to not get a fix within seconds even if it is horribly inaccurate) or an insensitive GPS antenna.

the snr numbers and the cold start fix tell us it is both, mainly software though.
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