What is your favorite GPS module ?  - Page 1
Forum section: electronics / projects

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: November 04, 2015, 01:32:33 pm
content: I am experiencing with various GPS modules, but I am not very satisfied with thetime required by the first fix.So my main requirement is rapidity of measure.I understand that this may be due to the antenna, as up to know I used onlythe PA6H (MediaTek MT3339)http://www.drotek.com/shop/en/home/513-very-small-pa6h-gps-breakout-board.html?search_query=gps&results=36and theA2235-H from Maestrohttp://www.mouser.fr/ProductDetail/Maestro-Wireless-Solutions/A2235-H/?qs=sGAEpiMZZMsjLMBIknjmksX9KsQcMAajJg0RANjS0qs%3dA little bit less easy to set up, but I would like something faster.Both contains an on board antenna.Any advice is welcome.

author: Isad
author_rank: Frequent Contributor
timestamp: November 04, 2015, 01:35:02 pm
content: The ublox 6m and the ublox 7m look pretty good i am using the 6m andso far its not been shabby.

author: kc8apf
author_rank: Regular Contributor
timestamp: November 04, 2015, 03:00:43 pm
content: Are you doing cold or warm starts? If you don't have a recent almanac, the receiver has to wait for a complete almanac to be received which can take up to 12 minutes due to the low baud rate and retransmit time. I believe the uBlox modules don't preserve the almanac between power cycles. It's up to the host to save and restore them.

author: oodavid
author_rank: Contributor
timestamp: November 04, 2015, 03:56:04 pm
content: I'm just about to order a pa6h breakout board, will let you know how I get on with it when it arrives. I've only heard good things so far.How fast do you need it to be?

author: edavid
author_rank: Super Contributor
timestamp: November 04, 2015, 06:13:40 pm
content: Navspark is worth a look... you can actually talk to the developers, so they may be able to help you get your TTFF to where you need it.http://www.navspark.com.tw/

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: November 04, 2015, 07:02:30 pm
content: Thanks for the link. It looks interesting. Have you used it ?

author: edavid
author_rank: Super Contributor
timestamp: November 04, 2015, 07:49:06 pm
content: Quote from: JacquesBBB on November 04, 2015, 07:02:30 pmYes, I bought a couple of boards from the IndieGogo campaign, and they seem to work fine, but I haven't tested them extensively.

author: Seekonk
author_rank: Super Contributor
timestamp: November 04, 2015, 08:13:11 pm
content: A friend is asking me for a GPS device that will output only speed for his vehicle speedometer. Is speed a parameter that is available or does it have to be calculated. Was thinking of using a mini 328 to generate the pulses he needs. Just started looking at the 6m.

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: November 04, 2015, 08:20:09 pm
content: The gps output the coordinates in various formats. So you need a microcontroller to decode it and compute the speed.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: November 04, 2015, 08:25:09 pm
content: I've used the MTK3339 in a custom design before (the module used on the Adafruit GPS). It took almost zero effort to design a board for it and get it running. According to the datasheet the time to first fix is 1 second on a hot start and 35 seconds on a cold start, which seems pretty accurate in my testing.http://www.adafruit.com/datasheets/GlobalTop-FGPMMOPA6H-Datasheet-V0A.pdf

author: uski
author_rank: Frequent Contributor
timestamp: November 04, 2015, 08:25:19 pm
content: uBlox MAX-M8Q is greatMany modules come into that form factor and you can make a board that can accomodate all of them especially if you add some jumper resistors to accomodate for the slight differencesSpecifically Quectel and Telit both make compatible modulesPricing depends of your volume of course... is it for hobby stuff or for work ?

author: suicidaleggroll
author_rank: Super Contributor
timestamp: November 04, 2015, 08:28:24 pm
content: Quote from: kc8apf on November 04, 2015, 03:00:43 pmYes it takes that long for the almanac to be broadcast from the satellites, but there's absolutely no reason the receiver needs to wait for the almanac to start acquiring and tracking. The almanac will tell the receiver the relative velocity of the satellite and its expected doppler shift, which will make acquisition easier, but if the receiver doesn't have that information it can still just scan the spectrum for the signal, which doesn't takethatlong. A receiver that takes more than a minute or two to get a position fix from a cold boot has a lazily designed acquisition system.

author: tonyarkles
author_rank: Regular Contributor
timestamp: November 04, 2015, 09:15:37 pm
content: Another vote for u-blox. I have a neo-m8t sitting on my desk and it's pretty awesome. Locks quickly, and piles of debug info available through u-centre if you're doing something unusual with it.

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: November 04, 2015, 10:50:04 pm
content: Quote from: uski on November 04, 2015, 08:25:19 pmMy job is my hobby.

author: Gribo
author_rank: Frequent Contributor
timestamp: November 05, 2015, 11:50:00 am
content: I have used the OriginGPS modules in the past. If you need very low power consumption (1.8V, ~40mA) and very small form factor (7x7mm), these might fit.

author: dave_k
author_rank: Frequent Contributor
timestamp: November 05, 2015, 12:18:13 pm
content: Quote from: tonyarkles on November 04, 2015, 09:15:37 pmCount my vote for uBlox as well. Have used them in countless situations (mainly the LEA-6H) and they are very reliable, with a very sensitive front end.

author: FreddyVictor
author_rank: Regular Contributor
timestamp: November 05, 2015, 12:54:09 pm
content: the latest uBlox modules are the 8 series which are able to use the GLONASS satellitesa cheap one is availableherenote that in the NMEA position data, the uBlox's have an extra digit of accuracy compared to MTK and em406 typesIn my experimantation (tested 5 modules all at once!) the M8N module was quickest to get a fix from cold followed by a uBlox Neo6 with a larger antenna I fitted

author: suicidaleggroll
author_rank: Super Contributor
timestamp: November 05, 2015, 01:28:28 pm
content: Quote from: FreddyVictor on November 05, 2015, 12:54:09 pmResolution != AccuracyYou can't expect any better than a few meters of accuracy with any of these cheap single frequency receivers due to measurement error and ionospheric delay. Resolution any higher than that is pretty much pointless.

author: FreddyVictor
author_rank: Regular Contributor
timestamp: November 05, 2015, 02:08:26 pm
content: Quote from: suicidaleggroll on November 05, 2015, 01:28:28 pmah yes,accuracywas the wrong word to use !the 'drunken' meanderings of these supposedly stationary devices does prove the point

author: linux-works
author_rank: Super Contributor
timestamp: November 05, 2015, 03:09:40 pm
content: ublox (working great with my arduino projects as well as rasp pi). 6m, 7m, 8m all work fine and are cheap as chips.

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: November 05, 2015, 05:57:13 pm
content: Quote from: suicidaleggroll on November 05, 2015, 01:28:28 pmThis is right, but an extra digit may be useful to measure the drift in a fixed location.