go_away

Author Topic: problem: my Venus GPS not getting fix  (Read 10854 times)

0 Members and 1 Guest are viewing this topic.

Offline madsci1016

  • Contest Winner
  • Supreme Robot
  • ****
  • Posts: 1,450
  • Helpful? 43
Re: problem: my Venus GPS not getting fix
« Reply #30 on: October 05, 2009, 07:05:56 PM »
I am very interested where this thread goes; before i drop $100 on a GPS i want to see it proven by some peers.

Rick<--- What accuracies are you observing with those models? 

Offline Rick Brooks

  • Jr. Member
  • **
  • Posts: 13
  • Helpful? 1
Re: problem: my Venus GPS not getting fix
« Reply #31 on: October 05, 2009, 07:44:13 PM »
Madsci,

For short term accuracy, with the EM-406A, I can normally get within one meter of the waypoint.

For long term accuracy (a few hours later) it could be several meters.

    Rick Brooks

Offline madsci1016

  • Contest Winner
  • Supreme Robot
  • ****
  • Posts: 1,450
  • Helpful? 43
Re: problem: my Venus GPS not getting fix
« Reply #32 on: October 05, 2009, 08:11:11 PM »
Hmm, I may get that sooner rather then later.

Let me know when you reach a verdict on the 407; it's datasheet says it's more accurate then the 406's datasheet. (2.5m compard to 10 ) If not, then it won't be worth the $30 over the 406.

It's kind of silly the 407 can track 50 sats when there are not even that many in the sky.

Offline madsci1016

  • Contest Winner
  • Supreme Robot
  • ****
  • Posts: 1,450
  • Helpful? 43
Re: problem: my Venus GPS not getting fix
« Reply #33 on: December 30, 2009, 11:28:56 PM »
Quote
Time for refund from Sparkfun for selling you and old revision?
I wish . . . I bought mine like ~2 months ago if I remember right . . .


I'll probably just buy several and try them all out. It might take a month before I report back, however.

Did you ever find one you like, Admin?

Offline AdminTopic starter

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,663
  • Helpful? 169
    • Society of Robots
Re: problem: my Venus GPS not getting fix
« Reply #34 on: January 05, 2010, 12:38:08 AM »
Well, I put in an order for one, but where I work shipping takes up to 3 months. Assuming it doesn't get lost in the system . . . government efficiency, you know . . .

I return to work next summer, so hopefully its arrived by then and I can play with it.

Offline madsci1016

  • Contest Winner
  • Supreme Robot
  • ****
  • Posts: 1,450
  • Helpful? 43
Re: problem: my Venus GPS not getting fix
« Reply #35 on: April 12, 2010, 06:53:13 PM »
Just to update everyone.

I removed my Venus GPS from SAGAR and installed a GS407 U-Blox5 GPS.

MAN!!! What a difference. The U-blox is awesome. While I'm running into issues with the accuracy of floating point when parsing my mission file, every time i repeated the mission, it was eerie how identical the same mission ran (Ran into the same car every time, the same spot on the curb, etc).

I recommend the U-blox to any robot builder, and I got it here with a nice adapter board.

http://store.diydrones.com/product_p/spk-gps-gs407.htm

Offline Rick Brooks

  • Jr. Member
  • **
  • Posts: 13
  • Helpful? 1
Re: problem: my Venus GPS not getting fix
« Reply #36 on: April 13, 2010, 03:12:51 PM »
Madsci,

Are you following the DIYdrone discussions about the U-Blox?  Particularly this one:
http://diydrones.com/forum/topics/for-gs407-ublox5-gps-4hz-diy

They do mention a new GPS unit that may be even better.

            Rick Brooks

Offline madsci1016

  • Contest Winner
  • Supreme Robot
  • ****
  • Posts: 1,450
  • Helpful? 43
Re: problem: my Venus GPS not getting fix
« Reply #37 on: April 13, 2010, 04:11:39 PM »
Madsci,

Are you following the DIYdrone discussions about the U-Blox?  Particularly this one:
http://diydrones.com/forum/topics/for-gs407-ublox5-gps-4hz-diy

They do mention a new GPS unit that may be even better.

            Rick Brooks


Lol, that's the one I have and linked to in my last post. I love it.

Offline Rick Brooks

  • Jr. Member
  • **
  • Posts: 13
  • Helpful? 1
Re: problem: my Venus GPS not getting fix
« Reply #38 on: April 13, 2010, 07:21:49 PM »
Quote
Lol, that's the one I have and linked to in my last post. I love it.

Which one do you have and love?  The older U-Blox, newer U-Blox, or the Media TeK?

          Rick Brooks

Offline madsci1016

  • Contest Winner
  • Supreme Robot
  • ****
  • Posts: 1,450
  • Helpful? 43
Re: problem: my Venus GPS not getting fix
« Reply #39 on: April 13, 2010, 07:54:07 PM »
This one exactly, bought from the DIYdrones store.

http://store.diydrones.com/product_p/spk-gps-gs407.htm

So it's the 407, which is the newer one, I believe.

Offline Rick Brooks

  • Jr. Member
  • **
  • Posts: 13
  • Helpful? 1
Re: problem: my Venus GPS not getting fix
« Reply #40 on: April 13, 2010, 09:17:50 PM »
I have one of the older units with 4 Hz update rate.  That is in the robot and I ran it a little last fall.  I should be able to run it more, now that the weather is better.

I did get a Media Tek and that seems to be even better, but I'm not going to stick it in the robot until I run the U-Bloc much more.

         Rick Brooks

Offline madsci1016

  • Contest Winner
  • Supreme Robot
  • ****
  • Posts: 1,450
  • Helpful? 43
Re: problem: my Venus GPS not getting fix
« Reply #41 on: April 13, 2010, 09:45:15 PM »
It's the same unit, different firmware.

I think the consensus in DIY is the older firmware at 2Hz was better (more accurate) then the newer firmware at 4Hz.

Offline Rick Brooks

  • Jr. Member
  • **
  • Posts: 13
  • Helpful? 1
Re: problem: my Venus GPS not getting fix
« Reply #42 on: April 14, 2010, 12:28:02 AM »
The newer firmware is 2 Hz, the older is 4 Hz, accuracy appears to be about the same.

Offline corrado33

  • Supreme Robot
  • *****
  • Posts: 611
  • Helpful? 11
Re: problem: my Venus GPS not getting fix
« Reply #43 on: April 18, 2010, 06:40:51 PM »
I really don't want to jump into this really complicated conversation.... but as for the altitude on civilian GPS units.  I read a while ago that A. the altitude measurement will never be accurate because of government restrictions (easy to build a GPS system for a missile if it has altitude as well?) and B. that to get a semi decent altitude measurement you pretty much have to be on a plain somewhere because it requires a satellite very near to the horizon, so if you're surrounded by mountains, you're SOL.  Just thought I'd throw in my 2 cents..

Offline Webbot

  • Expert Roboticist
  • Supreme Robot
  • *****
  • Posts: 2,154
  • Helpful? 110
Re: problem: my Venus GPS not getting fix
« Reply #44 on: April 18, 2010, 07:22:40 PM »
Yep the good ol' USA wants to confuse everyone by making GPS low res for non-military purposes.

They assume everyone else but them is a terrorist!

In the same way as they don't want in-coming missiles to be accurate then they don't want your robots to be accurate either.

So GPS hardware may be 'very accurate' but the 'government' insists that it gives a 'wrong reading'.

But then thats 'the price of freedom' - right?

There are some GPS devices out there which use Russian satellites. Russia seems 'happier' to give real information. Perhaps they cant afford all the hassle involved in giving the wrong answer.

So they are more accurate than US 'big brothered' devices..

NB Above is 'statement of reality' - not a statement of 'ideology'.
Webbot Home: http://webbot.org.uk/
WebbotLib online docs: http://webbot.org.uk/WebbotLibDocs
If your in the neighbourhood: http://www.hovinghamspa.co.uk

Offline AdminTopic starter

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,663
  • Helpful? 169
    • Society of Robots
Re: problem: my Venus GPS not getting fix
« Reply #45 on: April 18, 2010, 08:12:01 PM »
Before we go around bashing the US, and false spreading rumors, the US stopped the GPS reduction in accuracy like 10 years ago. DGPS made GPS so accurate even with the added intentional noise that it didn't matter any more.

Also, the Russian system is really only accurate in and near Russia.

Speaking of bashing other countries, when is Europe ever going to get their 'better' GPS system working? I hear you guys still haven't figured it out ;)
(I'm asking for trouble on purpose)

Offline madsci1016

  • Contest Winner
  • Supreme Robot
  • ****
  • Posts: 1,450
  • Helpful? 43
Re: problem: my Venus GPS not getting fix
« Reply #46 on: April 18, 2010, 08:28:12 PM »
the US stopped the GPS reduction in accuracy like 10 years ago. DGPS made GPS so accurate even with the added intentional noise that it didn't matter any more.

Yes, the US stopped that when Bush became president, so it's been a while. Altitude is very poor because it's even harder to calculate distance to the sats, and requires more sats to determine a 3D fix opposed a simple 2D fix.

Quote
when is Europe ever going to get their 'better' GPS system working? I hear you guys still haven't figured it out ;)

Zing!!! Also, they keep complaining that the US shouldn't have control of ICANN, even though we invented the internet.

Offline corrado33

  • Supreme Robot
  • *****
  • Posts: 611
  • Helpful? 11
Re: problem: my Venus GPS not getting fix
« Reply #47 on: April 18, 2010, 08:30:27 PM »
Before we go around bashing the US, and false spreading rumors, the US stopped the GPS reduction in accuracy like 10 years ago. DGPS made GPS so accurate even with the added intentional noise that it didn't matter any more.

Did I not mention that I read that years ago?   ::) I thought that the reduction was reduced, but I still think altitude on GPS is pretty messed up.  It makes sense though, if you have 5 satelites almost directly above you, there's almost no trigonometrical way to even measure altitude.  (I think)

Offline AdminTopic starter

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,663
  • Helpful? 169
    • Society of Robots
Re: problem: my Venus GPS not getting fix
« Reply #48 on: June 14, 2010, 10:39:54 AM »
I've decided to get the U-Blox5 that you guys recommended.

Is that $20 adapter a good idea? (It'll be connected directly to my Axon)

I ask because I can't make out the connection on the unit in the single image . . .


Offline madsci1016

  • Contest Winner
  • Supreme Robot
  • ****
  • Posts: 1,450
  • Helpful? 43
Re: problem: my Venus GPS not getting fix
« Reply #49 on: June 14, 2010, 11:12:12 AM »
Yes, I would recommend it. The GPS itself has some funky micro-miniature board to board connector.

What they don't tell you is you are suppose to epoxy the connector board to the GPS. See my forum post:

http://diydrones.com/forum/topics/ublox-has-bad-connection-with

Super glue worked fine for me.

And just to repeat; it's a super awesome GPS well worth the money. While SAGAR was driving into lakes with the Venus; Now it can navigate crowed parking lots full of parked cars without running into one. And I get locks in my living room while I'm working on code.
« Last Edit: June 14, 2010, 11:13:44 AM by madsci1016 »

Offline TrickyNekro

  • Contest Winner
  • Supreme Robot
  • ****
  • Posts: 1,207
  • Helpful? 15
  • 1.6L Peugeot 307 tuner
Re: problem: my Venus GPS not getting fix
« Reply #50 on: June 14, 2010, 11:16:13 AM »
I have had my sharing at finding a nice GPS too...
I got the LS20031...


Cold start in the open could be less that 20 seconds...tested! It has a battery to hold last known satellites...
Hot start can be as short as 1 - 3 sec... And I could see myself moving in a urban area, one meter each direction with
good accuracy...

I won't be spending money anytime soon, for a GPS again, but it's a nice nice choice...
And If I remember right, it was also recommended by some DIY drone guys ;-)

And comes 30$ cheaper... :p
For whom the interrupts toll...


P.S. I've been inactive for almost a year... Don't give promises but I'll try to complete my tutorials. I'll let you know when..

Cheers!

Offline Ro-Bot-X

  • Contest Winner
  • Supreme Robot
  • ****
  • Posts: 1,431
  • Helpful? 25
  • Store: RoBotXDesigns.ca
Re: problem: my Venus GPS not getting fix
« Reply #51 on: June 14, 2010, 11:42:58 AM »
Since the GPSbee from Seeed Studio uses U-blox5, it costs $55 and comes in Xbee form factor I think it's a better deal, as you can get a shield or adapter board and plug in whatever "bee" you need at the time. They also make a Bluetooth Bee that is cheaper ($23.50!) than a BlueSmirf module... and RFbee...
« Last Edit: June 14, 2010, 11:45:20 AM by Ro-Bot-X »
Check out the uBotino robot controller!

Offline madsci1016

  • Contest Winner
  • Supreme Robot
  • ****
  • Posts: 1,450
  • Helpful? 43
Re: problem: my Venus GPS not getting fix
« Reply #52 on: June 14, 2010, 10:50:46 PM »
Some of the expense of the DIY drones approved Ublox5 is it's super awesome helix antenna. And either you have to spend more on an antenna for the GPSbee, or it has some crummy on chip antenna that wouldn't compare to the quality helix.

And other units may be recommended by 'some' DIY drone guys, the Ublox5 is the "officially recommended" and official Ardupilot GPS. The Venus taught me my lesson, I'm not going to try to save $20 here or there,  when there's a whole relevant community recommending a single unit.

Now I wish Sparkfun would rewrite their GPS buying guide with actually tested results, not just sum up features on paper.

Offline AdminTopic starter

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,663
  • Helpful? 169
    • Society of Robots
Re: problem: my Venus GPS not getting fix
« Reply #53 on: June 15, 2010, 07:53:13 AM »
Some of the expense of the DIY drones approved Ublox5 is it's super awesome helix antenna. And either you have to spend more on an antenna for the GPSbee, or it has some crummy on chip antenna that wouldn't compare to the quality helix.
The adapter also has a battery that'll remember sats for a good two weeks - saving you from cold starts. It also has a built in charger to recharge that battery. Now if only they fix that loose connection that requires glue (I plan to try tape).

Quote
And other units may be recommended by 'some' DIY drone guys, the Ublox5 is the "officially recommended" and official Ardupilot GPS. The Venus taught me my lesson, I'm not going to try to save $20 here or there,  when there's a whole relevant community recommending a single unit.

Now I wish Sparkfun would rewrite their GPS buying guide with actually tested results, not just sum up features on paper.
The Venus (chip) is probably as good as it claims. But the Sparkfun breakout board was obviously badly designed and *never* even tested! I didn't bother looking further into it, but they probably didn't properly balance the antenna with a balun, or as people often complain about Sparkfun, they didn't "RTFD" ;D

That said, I'll never trust a Sparkfun GPS unit again. :-X

Spending 50% more to get 100% more is usually a good idea. :P

Offline AdminTopic starter

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,663
  • Helpful? 169
    • Society of Robots
Re: problem: my Venus GPS not getting fix
« Reply #54 on: June 23, 2010, 04:54:22 PM »

Offline AdminTopic starter

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,663
  • Helpful? 169
    • Society of Robots
Re: problem: my Venus GPS not getting fix
« Reply #55 on: June 23, 2010, 05:45:35 PM »
madsci, did you just use a duck antenna with the Venus like me?

A guy in the comments section on SF said this worked great:
http://www.sparkfun.com/commerce/product_info.php?products_id=464
Then again, SF could have changed the design before Feb 2010 when the guy posted . . .

someone else said:
Quote
My two boards had badly mismatched inputs--2 dB return loss. Was able to tune with 5pF capacitor in shunt. Sensitivity is poor, but works OK with active antenna when outside. Takes a very long time to first fix when signal is weak.


I've abandoned the Venus already, but I'm suspecting its an antenna problem . . .

Offline madsci1016

  • Contest Winner
  • Supreme Robot
  • ****
  • Posts: 1,450
  • Helpful? 43
Re: problem: my Venus GPS not getting fix
« Reply #56 on: June 23, 2010, 06:53:23 PM »
I used this one

http://www.sparkfun.com/commerce/product_info.php?products_id=177

But still, I remember it reporting good signal strengths, just crappy calculations and long fix. The Ublox really does blow me away.

Offline AdminTopic starter

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,663
  • Helpful? 169
    • Society of Robots
Re: problem: my Venus GPS not getting fix
« Reply #57 on: June 24, 2010, 07:56:14 AM »
I used this one

http://www.sparkfun.com/commerce/product_info.php?products_id=177

But still, I remember it reporting good signal strengths, just crappy calculations and long fix. The Ublox really does blow me away.

Thats the one a SF rep suggested using in a forum post on the Venus page. But the way he worded it sounded like they didn't actually try using it . . .

Offline madsci1016

  • Contest Winner
  • Supreme Robot
  • ****
  • Posts: 1,450
  • Helpful? 43
Re: problem: my Venus GPS not getting fix
« Reply #58 on: June 24, 2010, 12:46:57 PM »
I wouldn't take anything from SparkFun without a grain of salt.

They are still very much a 'started in a garage' company. Between shipping mistakes, evil(or idiotic) marketing ploys, mistakes in products and poorly thought out designs I try my best to avoid them. I have either saved money buying somewhere else or supported DIY websites like DIYDrones.

But they do have a competition I want to enter. Have to give them that.

Offline AdminTopic starter

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,663
  • Helpful? 169
    • Society of Robots
Re: problem: my Venus GPS not getting fix
« Reply #59 on: June 24, 2010, 01:03:32 PM »
They've served me well, except the Venus incident . . . and the bluetooth incidents . . . I still buy from them often.

That said, they refuse to sell my Axons unless I mark them down to $60 each >:(
They insist no one would ever buy an Axon at my price . . . lol . . . They completely ignored me about the Axon II . . .

 


Get Your Ad Here

data_list