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i-Blue GM-2 USB GPS Receiver
tcassidy
I tried a freshly constructed XP computer and Windows XP found and installed drivers for the device although they were version 4.28. I suspect Win 7 doesn't have those as they were not Vista certified (?).

I checked it with GPSView and it shows 1 Hz and 38,400 as I had set previously. To prove if the setting are stored in vram, I suspect you would have to leave it unplugged long enough for the internal battery to fail.

Terry
tcassidy
If you want to compare its cold start up time, GPSView has a button marked 'COLD' and a TTFF counter. In a relatively good position it gave 40 seconds.

Terry
Ken in Regina
Quote:
Originally Posted by tcassidy
If you want to compare its cold start up time, GPSView has a button marked 'COLD' and a TTFF counter. In a relatively good position it gave 40 seconds.

Terry
Thanks Terry. I had forgotten about the cold start and warm start buttons in GPSView and never noticed the time to first fix (TTFF) counter.

...ken...
MrUmbra
Quote:
Originally Posted by tcassidy
Great information! Would you have a BU-353 or other SirfStar III GPS to compare that with?

Terry
OK -- I collected twenty four hours of fix data from my BU-353. The test was conducted at the same location I selected for the GM-2.

The BU-353 reports the minute position with 4 places of precision producing a more conventional appearing scatter plot. The plot also exhibits an interesting grid structure that appears to correlate with the longitude/latitude scale factor ratio at 41 deg north.

The radial error histogram appears to be well structured.

$GPGGA,201813.000,4103.5866,N,07520.6890,W,1,07,1.0,426.5,M,-33.9,M,,0000*6C
$GPGSA,A,3,02,17,04,12,10,20,28,,,,,,1.8,1.0,1.5*34
$GPGSV,3,1,12,04,78,310,35,17,51,096,38,02,44,258,34,10,34,181,27*70
$GPGSV,3,2,12,12,28,312,35,20,14,042,28,28,12,162,24,23,10,079,*7B
$GPGSV,3,3,12,09,09,264,08,27,06,252,07,13,05,108,29,33,13,110,25*73
$GPRMC,201813.000,A,4103.5866,N,07520.6890,W,0.26,10.75,201010,,*21

Although CEP is greater than observed from the GM-2, the differential position between the two receivers is about 2.37 feet. I suppose that's an acceptable result for consumer quality devices.

--- CHAS
Attached Images
bu-353.jpg  
OneRVer
Marvin, I have two questions,

- Does the GM2 come wired for USB or do you need to wire it?

-Why the battery back-up? Does it not get power while plugged in to the usb port or will it act like a bluetooth? Just not understanding why it would need batteries.
tcassidy
The internal battery or possibly just a capacitor holding a charge is to maintain the satellite almanac information while the GPS is not connected to the computer.This allows the GPS to know where to look for satellites when reconnected and results in faster lock times (warm start). It might also store the almanac in non-volatile RAM so no internal power is required.

If it had no power, it would have to locate a satellite and download the almanac before it could determine where to look for other satellites.

Terry
Marvin Hlavac
... and yes, it does have a cable attached, so there is no work on your part required. In my case, all I did was: 1. I removed it from the packaging, and 2. I plugged it into a USB port of my laptop. I didn't even have to install the driver from the included CD, since it simply used one of the drivers I already had on my laptop from another USB GPS receiver.

The USB cable is of a decent size. I'm looking at it now, and in my estimation it may be approximately 6 feet long, or about 1.5 meters.
OneRVer
I ordered my GM2 around 1300 hrs, today, on Amazon. At 1500 hrs I received notification that it had been shipped.

Will let you know how the installation goes.

I will be more then happy to take any advice before hand.
Marvin Hlavac
Ordered at 13:00, shipped at 15:00! Nice, it should arrive soon!

Enjoy! I love how very fast the i-Blue GM-2 acquires first fix every morning!
OneRVer
Quote:
Originally Posted by Marvin Hlavac
Ordered at 13:00, shipped at 15:00! Nice, it should arrive soon!

Enjoy! I love how very fast the i-Blue GM-2 acquires first fix every morning!
Ordered on 11/08/10 received 11/12/10. Not bad.

Downloaded the driver, plugged in the GM-2, started up CoPilot version 8 Laptop, enter in the com port and the baud rate and off it went.

I don't have this kind of luck. Something must be wrong.
tcassidy
So, what baud rate did you enter?

Terry
OneRVer
Quote:
Originally Posted by tcassidy
So, what baud rate did you enter?

Terry
COM 16 BAUD 9600. I am running Window 7, 64 bit.

I am not sure how to download the other stuff on the disk. I was able to open and print the user guide but not sure on the other stuff that is on the disk. Any comments????
tcassidy
The other stuff is probably the useless version of GPSview that ships with this device. If your software likes the output right now, don't bother with it.

Sounds like the latest batch of GM2s are default 9600 bps instead of 115200 as the originals were. Interesting!

Terry
OneRVer
I knew 4800 was not right so I just picked 9600. Should I change it 115200??
tcassidy
No!! The speed you chose is what the GPS is sending. You can't alter that by changing the setting in your navigation program.

Terry
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