[Thumbgps-devel] GPS dongles

[Eric S. Raymond]

Chinavision CVGI-B07: $23
   This is the one with the unidentifiable 8-pin PL2303 clone,
no good because it probably doesn't pass 1PPS and we don't know 
how to get the parts for a clone,

Canmore GT-730F(L): $36
   Based on the SkyTraq Venus 5 chipset.  Claims 65 channels.  The
"datasheet" at the vendor site is a profoundly uninformative user
manual - can't tell what USB-to-serial chip it's using.  However
Amazon claims it's Linux-compatible.

GlobalSat ND-100S USB GPS Dongle: $32
   SiRF-III-based.  Claims Linux compatibility.  Uses the PL2303
driver (the documentation is silent on this but if you download the
Linux driver it has pl2303 in the archive name).  This looks like a good
target for blue-wiring or cloning; we should take one apart to see if
it has a real PL2303 in it.  My guess is it will; GlobalSat is not
a fly-by-night outfit.

SJ-5282 GPS Dongle: $25
   Based on SkyTraq Venus 6. No data sheet at the vendor site.  Will
inquire at service at sja.com.tw.  The enclosure looks familiar, I think
this one is sold under multiple names.

MightyGPS 100ND: $52
   Uses a GPS chipset called "M-Star MSB2122" not known to me.  No
datasheet at the vendor site.  USB adapter not specified.  I'll
email info at mightygps.com to ask.

uBlox 5 USB GPS stick
   Seen at http://www.laptopgpsworld.com. Listed for completeness; probably
uses the on-board uBlox USB that doesn't carry 1PPS out.

NaviLock NL-464US SiRF 3: Not for sale in US
   Uses SiRF-III. Can't identify the adapter, but it claims Linux 2.6
compatibility.

GiSTEQ GPS USB dongle: $39
   Can't identify either GPs or adapter.

Gotop GPS USB Dongle: $24.50
   Uses PL2303. No datasheet available at vendor site.

Here's the alibaba page listing Chinese products of this type:

http://www.alibaba.com/showroom/usb-gps-dongle.html

It looks like there are a handful of designs being resold under 
a lot of different names - the Chinavision and SJ-5282 in particular
are all over the place.

I think our best teardown target is probably the GlobalSat ND-100S,
but I'm going to use the alibaba page to shotgun the Chinese vendors
looking for (a) any that might carry PPS, and (b) what the chipsets
and USB adapters are.
-- 
		<a href="http://www.catb.org/~esr/">Eric S. Raymond</a>

Ideology, politics and journalism, which luxuriate in failure, are
impotent in the face of hope and joy.
	-- P. J. O'Rourke