GPS Module

Hi all

I’m building a prototype for a tracking system using GPS and i need some good precision and reliability since the prototype will be used on a remote area under some trees.
Does the GPS module (Part # GPS01-GM-325) has good quality? It is possible to attach an external antenna? Before i order this unit i would like to know what kind of issues/problems it may have…

Regards

GPS01-GM-325 uses the u-blox neo-6 engine. U-blox is a well known and respected company in the field. I doubt you will find an engine that is much better than this.

The data sheet quotes an accuracy of 2.5m CEP. This will be with a good antenna in a clear location away from any sources of reflections etc. The signal will degrade significantly if you are under trees (especially if wet). This will definitely reduce your accuracy.

Also, watch out for RF interference from your NETMF module.

Thank you for your reply.

By the pictures, the cable between GPS antenna and module seems very small, do you know if is it possible to add an extension (some sort of U.FI male/female)? I need to place the antenna 1 or 2 meters away from the GPS module

Regards

I don’t know how [em]much[/em] better, but I guess their NEO-M8 might be even better :wink:

http://www.u-blox.com/images/downloads/Product_Docs/GNSS-module-selector_Overview_(UBX-14000426).pdf

Yes you can get an ufl to sma adaptor cable fairly cheaply. You would probably want an active antenna for best results and would need to check that the GHI module can supply power for it.

The best solution might be to use a ‘smart’ GPS antenna puck with a serial or possibly USB cable. That way you are definitely seperating the GPS from any potential sources of interference.

The neo M8 is better because it supports glonass and Galileo. Glonass can be a bit unreliable. Galileo is going to start launching its FOC satellites from this summer so it would be well worth having in a year or two. I’ve not really used glonass so I don’t know how much it helps. I do know that it has had a few spurious incidents over the last year.

Of course you would need to build a custom board to use the M8.

Thank you all for the replies. I’ll try GPS module to see if is good enough for my application.

Regards

I prefer to use a USB GPS module. Results with the Seeed GPS modules have been less than consistent.

I have been using the Pharos USB GPS module that comes with Microsoft Streets. I have bought them for as little as $12 on ebay.

See https://www.ghielectronics.com/community/codeshare/entry/681

I am currently doing a Gadgeteer project with a USB GPS module, and it works great. I am using the latest 4.2 SDK.

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Hello Mike

On your pharos project you are saying "At the present time, there are difficulties running this code under Gadgeteer. ", since i’m planning to use a fez cerberus with a USB host module, does your code will work on it?

Are you using that USB GPS on your gadgeteer project? Which mainboard are you using? If there is a working hardware combination, i’ll be happy to use it.

Regards

@ geologic -

At the present time, the Cerberus firmware does not have USB host support. I don’t think there is support in the 4.3 beta, but I could be wrong?

I am using a Cobra II with the latest 4.2 firmware. in the past I had trouble with the USB GPS and gadgeteer, but it is working fine now.

Hummm… Cerberus doesn´t have native USB host, but i was thinking of using usb host module (Part # USBHT-GM-270) on cerberus and a USB GPS, do you think it will not work?

Regards

The host module is nothing more than a connector…It does not have an IC. This will connect a USB A connector to the USB host pins on your mainboard.

Dam… tricky boards… Too much “hidden” possibilities… I choosed cerberus because it is cheap and small.
I can use fez cobra eco (like Mike does), but i was planning to use 2 A-type slots from cerberus because i want to read some analog inputs and set some digital outputs. Cobra has only one A-type slot, but seems that the side has plenty of I/O ports. Are they easy to use/set like gadgeteer sockets? Is there any better option?

Regards

@ geologic - The better option would be to use the Cobra II Extender Board
https://www.ghielectronics.com/catalog/product/439

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Thanks all for your help, i think i’ll try cobra II with an external USB GPS.

I’ll post my conclusions here as soon i get all pieces together.

Regards

Just one more thing about Cobra II Extender Board… i see a 12V pin on the side, does it mean that cobra II motherboard is capable of output 12V? I need 12V to power a small IC with low power consumption, this way i can get it from the board.

Regards

No, it cannot. If you look at the Cobra 2 schematic, the wire it calls “12V” is the input from the barrel jack. If you supply greater than 12v on that, you’ll get something slightly lower than the input voltage because of the diode drop in D3. If that then happened to be closer to 12v than 9v for example, then you might be able to use it. But it’s not regulated to 12v like you would typically want to use.

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I want to use this system on a car, so i was worried about spykes and tension greater than 12V… I think i will try a LDO circuit or something like to ensure proper regulation.

Thanks

I’ve been using the Adafruit Ultimate GPS Module with the Cobra II to log my business mileage and which sites I’ve been working on. The module works perfectly without an external antenna and just sat on the passenger seat.

I have managed to build my prototype using Cobra II and an external GPS antenna, thank you all to your help, you guys pointed me in the right direction…

Regards