5hz GPS antenna w/USB?

**bmcmullin** · 09-28-2009, 12:21 PM

I am searching without success for a 5Hz (5 updates per second) roof mount GPS antenna/receiver.

We are currently using the Garmin 18x 5Hz but it has a serial connection and requires a wonky USB adaptor which is causing other problems (like sometimes when you reboot the XP thinks the serial adaptor is some type of ballpoint pointing device!!) Garmin's USB version of this only outputs the proprietary Garmin protocol.

The antenna is being used in a street-level imaging application (like Google Street View) so the more frequent updates are necessary for geocoding the images.

Any suggestions or links appreciated.

Regards,

Bill McMullin

**barnyard** · 09-28-2009, 12:48 PM

You can disable the "mouse" in device manager. That's what I had to do to for my Onstar GPS to serial mod.

**bmcmullin** · 09-28-2009, 12:55 PM

Originally Posted by barnyard

You can disable the "mouse" in device manager. That's what I had to do to for my Onstar GPS to serial mod.

Thanks Barnyard,

Yes, we did figure out how to disable the offending device but it seems to mysteriously come back at times on reboot.

I believe I may have found what I was looking for in the Navibe GM720, which claims to emit updates 10 times a second. For only $28 per, I'm a little suspicious. Check it out here http://www.buygpsnow.com/navibe-gm72...abled-779.aspx

**justchat_1** · 09-28-2009, 02:18 PM

Or try this:
http://www.pcmaritime.co.uk/leisure/...pingmouse.html

**FPeter** · 09-28-2009, 05:59 PM

Originally Posted by bmcmullin

Thanks Barnyard,

Yes, we did figure out how to disable the offending device but it seems to mysteriously come back at times on reboot.

I believe I may have found what I was looking for in the Navibe GM720, which claims to emit updates 10 times a second. For only $28 per, I'm a little suspicious. Check it out here http://www.buygpsnow.com/navibe-gm72...abled-779.aspx

"It can track up 20 satellites at a time and update data position every 1 second."

its a simple Sirf3 stuff, gives 1Hz only...

i got my Quectel L10 module last week, but i had no time to built the receiver with it - so i did not test it by this time

the documentation says that its update rate is up to 10Hz - but its true only with special firmware from chipset supplier (MTK3329). with default firmware, the 5Hz is guaranteed, but if You need faster, You should get in contact with Quectel...

**bmcmullin** · 09-28-2009, 06:20 PM

FPeter,

You are right. The folks at BuyGPSNow confirmed that there is/was a typo on the site. It's funny because the same typo was on the manufacturer's site.

Re the Quectel unit, I'd be delighted with 5Hz but unfortunately I'm not an electrical engineer! Correct me if I'm wrong but the module needs an enclosure, cable, antenna etc?

Just out of curiosity, what are you doing with the module?

Originally Posted by FPeter

"It can track up 20 satellites at a time and update data position every 1 second."

its a simple Sirf3 stuff, gives 1Hz only...

i got my Quectel L10 module last week, but i had no time to built the receiver with it - so i did not test it by this time

the documentation says that its update rate is up to 10Hz - but its true only with special firmware from chipset supplier (MTK3329). with default firmware, the 5Hz is guaranteed, but if You need faster, You should get in contact with Quectel...

**FPeter** · 09-29-2009, 09:26 AM

Originally Posted by bmcmullin

FPeter,

You are right. The folks at BuyGPSNow confirmed that there is/was a typo on the site. It's funny because the same typo was on the manufacturer's site.

Re the Quectel unit, I'd be delighted with 5Hz but unfortunately I'm not an electrical engineer! Correct me if I'm wrong but the module needs an enclosure, cable, antenna etc?

Just out of curiosity, what are you doing with the module?

yes, as you said, cable, antenna and power supply circuit is required, i will connect them myself. it has native USB support with virtual serial port emulation, so another circuit is not required...

but there are several receiver model on the market with MTK chipset, and most of them can be tweaked to 5Hz (if 1Hz is the factory setting)... You can find more info about modding on this forum: click and click

**Marvin Hlavac** · 10-01-2009, 08:11 PM

I'm not aware of any USB magnet-mount consumer GPS receiver on the market right now that is capable of more than 1Hz. However, if you could use a unit without magnet, then I think there are some Bluetooth, and ever Bluetooth/USB (dual) units that can do 5Hz and even 10Hz. I think they are mostly based on the MTK2 chipset.

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Laptop GPS World

**FPeter** · 10-02-2009, 02:05 AM

Originally Posted by Marvin Hlavac

I'm not aware of any USB magnet-mount consumer GPS receiver on the market right now that is capable of more than 1Hz. However, if you could use a unit without magnet, then I think there are some Bluetooth, and ever Bluetooth/USB (dual) units that can do 5Hz and even 10Hz. I think they are mostly based on the MTK2 chipset.

hmmmm, what?

how do You mean that? USB vs. Bluetooth... Bluetooth is why better? Magnet is why problem?

USB in case of Sirf3 / other old: serial Rx/Tx from chipset connects to a USB transciever
BT in case of Sirf3 / other old: serial Rx/TX from chipset connects to a BT transciever

USB in case of MTK2 / other new: internal USB slave support with virtual serial port
BT in case of MTK2 / other new: serial Rx/TX from chipset connects to a BT transciever

its clear, there are no difference between USB and BT connection in case of older stuffs, and if there are any difference between USB and BT in case of newer chips, then the advantage is on the side of USB - might achieve higher speed - but it does not matter, speed of serial is enough for 5-10Hz

so, in case of similar chipset with similar settings, there is no difference! only the annoying BT sync and RF interference against the robust cable installation...

**FPeter** · 10-05-2009, 11:52 PM

i finished the pre-alpha version of the receiver with the MTK3329 Quectel L10 module, and its very good. the 5Hz refresh rate is real, gives different datas 5 times in every sec. the reaction of speed measuring (i prefer iGo2008 PC) is much more sensitive than with Sirf3 Royaltek, and its reception is fine with a small 15x15mm antenna...