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calevepas

5Hz Update GPS!

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GpsPassion did a comparison between 1Hz and 5Hz GPS receivers. The results speak for themselves.

They used the iBlue 737 GPS receiver with an MTK chipset inside. Now, Spark Fun has started carrying a 5Hz GPS module made by ETek.

Since both the MTK and the ETek are said to support 5Hz updates & have 158dbm sensitivity, would it be safe to assume that Etek's module will provide the same performance?

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I just got the Etek unit. It is really fast. The only issue is that you need a backup battery to save the config. Otherwise, it starts up with the defaults (1Hz and 38400 baud).

Edited by docphi

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You could use a small PIC to download the configuration to the GPS on powerup, then go into powersaving mode afterwards. This would remove the need for a battery backup to store the config, although I'm not sure what else it might need to store as well.

The hard part is finding out what commands to send it, as a quick look didn't dig up any info. Reverse engineering by the com port traffic would probably be the last resort, but not too pretty.

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Now where's the fun in that ;)

Out of interest, what kind of backup times do you get with those things?

Edited by zeldorf

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No fun at all! :P I'm going to try and program it from a Basic Stamp on startup. Just need to find the command set. As far as backup times, I really don't know. Maybe someone else more worthy than I can chime in.

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Connect the cap neg to the ground from the GPS. Connect the cap pos to the battery line from the GPS and your power line.

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will this new super GPS unit you talk about, perform good when placed close to a 500mW 2.4GHz video transmitter ?

all my EM406 can not work close to transmitters of any kind,

and I have tested 6 units !

thay all degrade alot or fail to lock,

I have modified a few of them, and now they work fine.

but I will be happy to find a compleete GPS unit with small patch antenna,

without this problem, and also I would like the same accuacy or better as the SIRF STAR 3 chip set deliver.

PS: We must have the commands information avail for the modules !!

so we can setup the baud rate and nmea pakages we need.

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will this new super GPS unit you talk about, perform good when placed close to a 500mW 2.4GHz video transmitter ?

all my EM406 can not work close to transmitters of any kind,

and I have tested 6 units !

thay all degrade alot or fail to lock,

I have modified a few of them, and now they work fine.

but I will be happy to find a compleete GPS unit with small patch antenna,

without this problem, and also I would like the same accuacy or better as the SIRF STAR 3 chip set deliver.

PS: We must have the commands information avail for the modules !!

so we can setup the baud rate and nmea pakages we need.

Command set in the works...

http://forum.sparkfun.com/viewtopic.php?t=6446

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Guys,

I've been experimenting with the Etek GPS and Inspire OSD. Mr. RC-Cam kindly updated my firmware for 38.4bps. There's a sample video posted at RC-Groups. It's a lousy render and I've got dropouts which I haven't quite worked out yet. However, you'll get the idea. You can see the data update in real-time. Very cool! :D The Inspire's higher baud rate is very stable and I've placed a 500mw transmitter right next to the GPS without any blocking issues.

K

http://www.rcgroups.com/forums/showthread.php?t=663344

Edited by docphi

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How 'bout this little puppy?

http://www.sanav.com/gps_engine_board/FV-M7_FV-M11.htm

32 channels / 5HZ / external MMCX connector? about $90 MSRP.

Docphi

Awasome job man! so you managed to hack the 6 pin EM406 connector to work with this module?

Mr.Rc-Cam

Any chance you will integrate compatibility with the ETEK 5 HZ in all your Inspire modules as default? I think many people would be happy to see this 5hz module for sale at the inspire page ;) !

Gizmo

Edited by gizmointheskywithdiamonds

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Docphi, it is a treat to see the real time data! Do you turn off any of the unused NMEA sentences when you setup the EB-85A? Or, do you just tell it to use 38.4K baud and nothing more?

I think many people would be happy to see this 5hz module for sale at the inspire page

I would like to do that. I will need the binary protocol so that the Inspire can set the EB-85A for 5hz. It is only a matter of time before someone publishes the info (plus, I'll try to get the info from the mfg as well).

Before formally phasing in the software that Docphi is using, I need to do some in-house validation on it. It is on the to-do list. In the meantime, the special software release that he is using can be re-flashed by the user using the Inspire serial bootloader cable. The special software, and instructions, will be provided to users that request it.

Regardless, I am trying to convince myself to do a group buy of the EB-85A's for forum members. If I can get a few serious buyers, I'd be happy to to do that. I would target it for $80 + shipping, which makes it a pretty good deal. If there is any interest, please let me know in this thread: http://www.rc-cam.com/forum/index.php?showtopic=1461

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If you have time (and don't mind), I have a couple of experiments for you to try.

(1) Does it still work well with Inspire if the GPS's default sentences are all enabled? Do the data updates slow down, or does the Aux servo feature get jittery, or does the tach accuracy suffer?

(2) What happens if all of Inspire's data fields are turned on? Does the data updates slow down?

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If you have time (and don't mind), I have a couple of experiments for you to try.

(1) Does it still work well with Inspire if the GPS's default sentences are all enabled? Do the data updates slow down, or does the Aux servo feature get jittery, or does the tach accuracy suffer?

(2) What happens if all of Inspire's data fields are turned on? Does the data updates slow down?

Works fine on the bench. I'll let you know what happens in the air.

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Works fine on the bench. I'll let you know what happens in the air.

Did the flight test show any issues with all NMEA sentences turned on and all Inspire Data fields enabled? Any new videos to share?

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I was just reviewing the video from todays test. I need to do some further testing, but, I think there may be some problems with the extra data being transmitted. My initial feeling is that the unused NMEA sentences should be turned off to maximize bandwidth. The data is lagging slightly and I keep losing the altitude info. I don't think it's a function of enabling all of Inspire's data fields. I'll have some more results Monday (I'm working this weekend :angry: ). At any rate, it works fine with the unused NNEA sentences off.

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The data is lagging slightly and I keep losing the altitude info. I don't think it's a function of enabling all of Inspire's data fields. I'll have some more results Monday (I'm working this weekend  ). At any rate, it works fine with the unused NNEA sentences off.

Thanks for the report. If turning off the unused sentences makes it work perfectly, then that will be ideal news. Please keep all of Inspire's data fields turned on during test to ensure that the additional OSD overhead is not involved with the trouble.

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does the EB85 module perform as the MTK737 or MTK818 ?

the delay and off track "problems" are only a few meters with the sirftstar 3

in city usage, what about openland measurements ? seen any errors there ?

I have visited a special checkpoint at this exact location :

N55 43.5270 E012 27.2194

and my GPS with EM406 module said I was 1.3 meters off.. who cares ?

it is accurate enough for me :-)

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does the EB85 module perform as the MTK737 or MTK818 ?

I hear it is a MTK-3301 chip set.

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