#22 Comparison of precision between Neo-M8N and Neo-6M Modules
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- čas přidán 8. 09. 2015
- In this video I compare the "old" Neo-6M with the new Neo-M8N module. I am interested especially in altitude precision, but compare also horizontal precision.
Both modules are compared with the precision of a pressure sensor BME280 in measuring exact relative altitude.
I also show how to change the Arduino TinyGPSplus library that it works with the Neo-M8N module.
Links:
Video about precision altitude measurment: • #16 Exact Measurement ...
ublox configuration video: • 10Hz U-blox binary GPS...
u-center download: www.u-blox.com/en/evaluation-...
TinyGPS++ library for Neo-M8N: github.com/SensorsIot/TinyGPS...
Video about direct input to Excel: • #9 Arduino Data Logger... - Věda a technologie
Note that it takes 11-13 minutes for the sats to download the almanac and ephemeris files (in a clear line of sight to the sats) to the GPS receivers (these files are the data resourced by the rcvrs for their "hot start" function to avoid sat search time). These files expire every 9 days and new ones are released to the sats for download every Monday.
Thank you for this information. I did not know that.
Hi I am interested in this topic. How can this files be provided to GPS modules from wifi or gsm? This can help fast the process of locking and improve battery operated devices battery life.
Ephemeris data takes 30 seconds to download and is all you need for a GPS fix though. Almanac was useful for the early GPS receivers that had low sensitivity and needed help knowing where to look for the satellites using an approximate solution, now not so much, if at all ;-)
@@ShirishJadav162 Almanach and Ephemeris data are directly broadcast by the GPS satellites.
This data along with date and time are the only data transmitted by the satellites.
@@ShirishJadav162 No.
Dear,
I've been watching your video. Its a great job. Thanks for your job, it is very instructive !
+EclisiaSong Thank you for your compliment!
For anyone who's trying to use NEO-8 for more than GPS and GLONASS satellites, you'll have to enable it at 'GNSS config' AND change the NMEA protocol to version 4.10. As soon as you set it, you'll be able to receive Beidou and Galileo satellites. But you can only set 3 GNSS services at a time(for neo-8), and to change between then you must leave only 2 services, save it, and only then enable the third you'd like.
And I have also found much better reception if you desolder the SMA connector if you're not gonna use it. If you're looking foward to use an active sma antenna, then you must desolder the C2 capacitor. This only applies to the M8 boards with soldered ceramic antenna
Thank you for the additional info!
Very helpful information about the precision of these GPS modules.
(I am not surprised that a Swiss should be so interested in precision.)
(Yes, they are very well known for their precision chocolate, mmmhhh...)
Thumbs up for the informational video and "here is the guy with the Swiss accent again."
Thanks for your compliment!
Thank you. Your presentations are logical and clear.
I love Sweiss
You are welcome!
Andreas, as always, an excellent video. I am researching the Neo-M8N and interested to hear your analysis and tips. Thank you for sharing.
I never used GPS chip since then. You you will find much more information at other sources.
Thanks, Mr. Spiess for another very helpful production!
My pleasure!
OMG, you replied to my post; it's like getting attention from my favorite celebrity!
Seriously though, thanks again for this, and for the other very useful productions that are helping me understand my new NanoVNA. @@AndreasSpiess
Thank u for the detailed testing, greatly appreciated, and great channel!!!!
:-)
Great video. Very helpful. Thanks!
:-)
do you have some altitude code examples for the nodemcu esp8266? I can't seem to find a good example of sea level adjustment.
Andreas Spiess = loves deep details = thats why ı love his style. thanks.
I think the actual chip is 3v only, but the board. Isn't there a 3v regulator on the module? I'm waiting on my neo-m8n module, and judging by photos online, it looks like the module can accept 5v and regulates down to 3v. It's difficult to find a definitive answer on these little breakout boards.
When I clicked on the video, I didn't expect such a good video like this
Glad you liked it! (There are many more videos on the channel ;-)
More than two years later and uBlox has released the neo-M8P which is capable of centimetre level accuracy with corrections. I have found with good view of the sky that the neo-M8N can get down to meter level accuracy without corrections.
As soon as I get a board with the M8P on it from China I will try it. RKT is interesting for me.
under the open sky place outside you can achieve desired accuracy
line of sight cleareance required
First, thanks for the video; I have two questions:
1) Does a Neo-6M sketch work with Neo-8M?
2) Is it possible to extend the GPS antenna? Can any wire be used from the beginning of the board to the other end?
Maybe a tnc to sma port will help
@@tankingblitz Tks
Helpful.. Wondered if the issue about updating the GPS string format is also the case for the NEO-M8Q-0-01 Card variation?
+Lisa Pierce I do not know. I did not use the device since a while
is 6m gps module works and get the data if I connect it to computer through avr atmega 128 ? bcause My program that I set to convert the NMEA data into readable longtitude lattitude google maps doesnt work
Sorry, but I do not exactly understand your problem. You can use GPS modules with Arduinos. There are many tutorials available.
Many thanks Andreas...
awesome! really excited to use this with my oled. :-)
:-)
SUPER !!
Thanks for your job !!
You are welcome!
just what i was looking for, allthough i need some info on using this gps and a cmpass unit for maritime use oon a sail boat. which serail to ubb do i need. thanks again
Glad I could help
I need your help. Do you have a video that shows how to sync the Nextion RTC with the satellite RTC in Arduino? I just got the Neo-M8n for an electric car project along with a Nextion 10.1 to use for the dashboard read out and I want to have it sync the Nextion RTC with the satellites at bootup.
This job has to be done in software. You need programming skills for that.
Hello,
Thank you for sharing your knowledge.
Please both 6M and 8M, can they keep RTC in sync?
Does 6M have any significant differences?
(More than a second?)
+Rtek1000 I do not know because I never used this functionality
If anyone else needs this, the 6M can get time from GPS and you can sync with your local board (e.g Adrduino), with TinyGps library you get: gps.time.hour(), gps.time.minute(), gps.time.second(), etc.
You get them faster than position lock and is very accurate.
hello mr. spiess, what is your desktop's resolution? looks higher resolution than 1920x1080, or did you shrink your system font size and icons separation?
2560x1440 on two monitors and 1920x1080 on the third. For the videos, I usually use 1920 or reduce it to 1280 x720 (for Sketches etc.)
Hi Andreas,
thanks a lot for good explanation of GPS modules. I would like to know , if you have the info obviously, what can I do with my LEA-6H-0-002 gps module. What I would like to do is:
- run it to calculate position at 10Hz instead of 5Hz ( it seems it's not possible with it!! )
- when you speak about profile (Navigation Modes) what really happen in the module? What does it mean?
My application is gps module mounted on a Quadcopter to perform RTH, Position Hold and so on.
I'm using UBX protocol.
Do you suggest to buy another more performing module?
- Is it possible to flash new firmware in the LEA-6H-0-002 ? I raise the question to u-blox company without success....
Thanks in advance if you can help me on this.
Regards
Fiorenzo
+Fiorenzo Giust I never looked into update rates. So, I have to guess: Neo-6 offer max 5 Hz update rate. Neo-8 with GPS satellites only 10Hz. But there are many other possible bottlenecks:
1. Connection controller to GPS module: If you use Serial connection: Serial is very slow (usually 9600) The chips should be able to use higher speeds, however you have to change it in setup.
If your board offers I2c or SPI pins you could also use these interfaces. Then, transmission speed should not be an issue anymore.
2. I do not know which MCU you use, but this could also be the bottleneck. The MCU on my self balancing robot at least is quite busy stabilizing hte whole thing.
3. Another question is: How far can your quad move in 0.1 sec? If it is less than the precision of the GPS you might not get much more information.
The ublox chips are very much configurable. with their u-center software. You can download it free from their homepage. This software also offers a possibility for Firmware update if the company offers one.
ublox does only sell their products in very large quantities, so I can imagine they have no customer support for end-useres as we are.
Hope, this helps a bit...
Nice video Andreas . Perhaps it is time for a new video with european Galileo sats results . I have read that 30 of them are already in operation and are supposed to give less than one meter accuracy !
Thank you for your proposal. For the moment it is not on top priority. But you never know!
I have a NEO 6M are there any advantages on ugrading firmware?
Where can i finf these scripts? Thanks in advance!
I think, I never updated the firmware. U-blox has its Software u-center to do an update.
Hi can you make a video on using these sensors for differential gps. Ive seen articles saying this can approach can improve accuracy alot.
Yes
Thanks for testing. Developing a device for measuring car acceleration. Seems to be good module for this.
Should be possible. Acceleration can be calculated from speed change per time.
Yes, but I tried SIM28M GPS Module, and it is very slow even in 10 Hz mode - when I launch my car it detects speed after 1-1.5 seconds delay. This U-Blox 8 is much faster and very accurate. And altitude measurement is good too - device will detect if someone accelerates downhill and marks the results as cheating.
+P Kav As you saw, the height measurement is not very accurate for the two sensors tested. Of course, I do not know your requirements.
Hi
Can u tell me is it possible to improve my accuracy by using 2 GPS module NEO - 6 M (comparing information)?
I mean in Arduino or create app in Delphi XE8 or C#, or any other methodes?
I am not an expert in GPS, so I cannot answer this question. There is a technology using 2 GPS modules and fix one to a particular place. Because you know exactly, where this module is, you can calculate the measuring error. And this difference is then transported to the mobile GPS to enhance quality. There is a link to this principle down in the comments of one of the viewers.
GPS module with RTK tec will be better. About 0.1m CEP if I remember right. But it require static position. If the receiver is moving, then the accuracy will be bad.
You said the NEO-6 can only receive American (USA) satelites ? What if I try to use it in Canada (Province of Quebec) ? Will it work and if so only with the USA available satelites ? Thanks for your reply..
American GPS satellite can be used everywhere (up till now ;-)
my M8N uses $GPGLL NMEA sentence for lat lng. Shouldn't it be included in the defines?
I do not know. This is an old video.
Great work done...
:-)
Gruezi "guy with the Swiss accent".
Some people might say I have even more a Swiss accent even though I moved from the Berner-Oberland to Seattle a half a century ago ;-)
I really enjoyed watching your video and learning many things.
Being Swiss we just have to be precise.
As a boy I used to walk miles to get to a watchmaker's storefront window to set my watch to the exact time displayed there.
... and soon my "official tested (chronometer stamped)" watch would be wrong again before the quartz crystal electronics.
Nice to hear from a second Swiss in Seattle on this channel ;-). In one of my last videos I created a transmitter for a time reference signal like the DCF77. And my videos air every Sunday 9 am Bern time.
@@AndreasSpiess Nice to hear about your videos. I will certainly follow them. And the DCF77 signals could make life easier,
One thing I forgot to mention is that people now need treadmills, gym memberships (and mountain bikes) since they don't have to walk to a far-away Schaufenster anymore to set their watches (or cellphone clocks) ;-)
Thank you for your fantastic video
You are welcome!
great stuff...have you any details regarding the usb serial converter please.?
cheers
These are standard boards. You find them on AliExpress.
Good day sir. What sensor would you recommend for a LORA tracking device to use as less power as possible with accelerometer?
I have no overview over GPS modules and I do not know if anybody produces combined GPS/accelerometer chips :-(
@@AndreasSpiess I appreciate coming back thank you. I am from South Africa and cattle theft is a big problem. I want to help the farmers but cost is a big issue. I am still learning and enjoy your channel a lot.
Werner Herzog does youtube videos now? Great video btw, do you have any videos that talk about how we can setup 2 RTK receivers using Arduino? To get cm level precision?
Maybe I will look once into RKT when I have time. Seems to be interesting...
that would be amazing, thank you! A lot of people are searching for this
My neo - 6m gps module giving completely error in latitude and longitude.... What to do
..
I do not know. Did you wait long enough for the first fix of the position (many minutes if the device is new)
Thanks mate! Is bro 6M suitable for APM 2.8 flight controller?
I do not know. I have no Quad experience.
Do you know any app to make same analysis in Android? I want to see what precision of my GPS antenna from my car.
I am an IOS user :-(
Thank you for this information. It is very helpful. I am planning on using the 6M for elevation sensing. Do you think that filtering/averaging the data over the course of an hour would give a reliable reading? At least I know now that it won't be worth changing to the 8M.
Averaging can for sure help, but maybe not only seconds. Maybe you also consider RTK?
I find when my model plane lands, the error in location looks like the
ones you recorded here. But while flying, it is smooth as silk.
Can you explain why?
I am no specialist in GPS technology :-(
could be related to signal reflections at lower altitude
Hi...
Is it possible, using a neo-m8n and U-center, to see the almanach / ephemeris data broadcasted by the GPS satellites ?
I do not know. I never needed these informations.
@@AndreasSpiess Thank you....
I could retreivee these infos in the past, but since i worked with several GPS modules, i do not remember which one.
@@ve2zzz you can see whether the info is available for each satellite but I don't see a way of downloading the actual data in uCenter. You can do that with an old SiRF receiver and the SiRFDemo software.
My neo m6 doesn´t find the location, I live in Spain. I connected it to 5 volts supply, as I´ve seen on some tutrials, could it have burnt the module? May they be defectuous?
Usually they should also work with 5v. Are you sure you did not mix the wires (eg. TX and RX or VCCand GND)?
@@AndreasSpiess thank you for your response. I think I connected them well. If I didn't, is there a chance of burning the chip?
Yes.
Good comparison, thank you! I have been wondering if to replace the NEO-6 with 8 in my DJI Phantom 1. There are wired modules available for such a low price, that it would be nice to try. But I also know how GPS works, thanks to years of MTB/cross-country biking, recording every ride. It just is not 100% reliable. What is interesting, is that the best weather for GPS has been very humid or even rainy weather. The worst is dry and clear with moderate winds. It must have something to do with the conditions far above the ground (several kilometers), but on the average I had one or two days in a year when unassisted GPS, even sensitive one, did not get fix. Tried everything I can, power off the GPS (Holux GPSlim 236), leave it on the ground still for minutes, smash it on the ground throwing the battery away etc. It normally gets fix in half a minute as expected, but in that dry weather it only got fix after riding for like 2 kilometers. That is just random. I really hate those days :D
Strange behavior... Not as expected. The only GPS I use regularly is the one in my car. And it never happened, that I did not get a fix after a while. So, it must be something with your GPS module.
The difference of the -6 and the -8 is, that the -8 sees also the Russian satellites which can help in difficult situations.
Andreas Spiess there's nothing wrong with the GPS, it's sensitive and very consistent, SirfStar III. Just a certain weather situation does that, rarely. I used it for years, twice a day, so I have comprehensive experience. The same could happen on my phone's gps on the same day.
Andreas Spiess M8 vs M6: it's not just adding GLONASS, there's always other improvements too. Like GPS-only receivers differ on sensitivity, noise tolerance, output noise (either real or filtered)...
hi sir my neo6m antenna - + with multimeter beeps is it normal and when ı touch it spark on my finger. the neo6mv just arrived today also
I do not know. Maybe you use the module as intended. Then you see if it works.
@@AndreasSpiess ı love watching your videos. thanks Sir.
Hello does the value of the gps change if I change the position of gps module from 10-15 cm from the the actual position
Are these gps modules so accurate
No.
@@AndreasSpiess so at what distance will the value of GPS change
hello, where did you get your M8N from ?
cheers
Brett
From Aliexpress
Can you tell me which GPS is best for more accurate position, because we have lots of gps modules available in market like SKG13BL, ultimate, ublox neo 6M, NEO 6M, NEO M8N, ublox neo7M, sain smart neo 6M.
Please help to find out best gps module that can work with either Arduino uno, nano, Node mcu E866 etc.
Thanks waiting for your reply.
I did not do such tests so I cannot tell you.
Which one will work with INDIAN GPS SYSTEM (NAVIC) ?? PLease Reply !
I do not know
Hi Andreas, i was wondering if the Ublox m8u is compatible with the shield that you are using for the m8n
I do not know the m8u module.
Hi thanks for the reply, just wondering , is it possible to buy the shield by itself for the m8n?
I do not know But I am sure, Google knows.
Thanks for the reply, btw may i know where did u get ur m8n from, from what i see from ublox's website, they only provide the gps chip. Therefore i was wondering where you got that breakout board for your m8n.
Please have a look to the new Neo M8U
Maybe in the future
hi i can find the TinyGPS++ file for the neo m8n on github can you replase the link or send me the file manny thanks
I updated the link in the vido: github.com/SensorsIot/TinyGPSplus-for-Neo-M8N
I am testing for the first time. I have a accesspoint running on xiao esp32s3 and the neo-6m is displaying data on http web server. I only see one binary byte. I have to be outside for the blue led to turn on. I was going to use this with a drone, so i purchased 3 for 3 test prototype. I feel like this is not good for my project.
I have it powered up outside for 30 minutes and i only see one byte displayed.
I would connect the neo-6M to a PC running the ublox software to test if the GPS module works. Only then, I would continue with the ESP32.
Hoi Andreas, müsste das GPS Modul nicht blinken bei Satellitenempfang? Grüsse aus Oensingen
Das weiss ich nicht mehr :-(
Great, thank you and congratulation!
You are welcome!
I recently read that these modules can be programmed with the u-Center software to output a GPS-stabilized frequency between 0,25 and 24 MHz instead of the usual pulse per second (PPS), so that they can be used as a cheap but stable frequency normal. Some modules have a pin to output the PPS-signal, some must be modified to pick up the signal from the input of the pulse-LED. It outputs a square wave of the desired frequency (and Duty cycle), set via u-center.
If you find that useful or at least interesting, please make a video on that. Thanks for your excellent work. 73!
Yes, they can be programmed as you describe. Unfortunately, the output has phase jitter and cannot be used directly for RF applications. This is why people build GPSDOs which use a stable OCXO/TCXO and correct it long term with the signal you described. 73 de HB9BLA
Which one is best - Neo-M8N OR Adafruit Ultimate GPS (G.TOP - LadyBird 1 [FGPMMOPA6H-MT3339])?
+paresh chaudhary I never used the MTK3339, so I cannot tell you the difference. Please keep in mind, that the antenna size is very important for performance.
+Andreas Spiess MAny many thanks for taking your time.
How can you expect the difference between these measurements? All you do is sensing of time differences in receiving of modulation signal of ca. 1 MHz from different sats, not a carrier of 1,5GHz. The way to increase measurement precision is to use differencial method with reference sycroised to time generator of sattelite. Maybe the way to go is to use NEO8P dev kit with LoRa?
These sensors have to be quite precise. So you can expect differences. And not all chips listen to all satellite systems. This can also lead to differences.
GN/GP well spotted! (I noticed some differences between Neon6m and 7m as welk)
Since then I never did any comparisons between GPS modules.
is SPI interace enabled in those modules?
I only used serial
Did you used filters like Kalman filter to normalize the data?
No.
Hello Andreas, do you know how to calculate Accuracy in GPS system? is it possible using HDOP or PDOP?
I am an electronics engineer and do not know a lot of these things. I am sure, you find specialised info in the internet. I was more interested in the relative accuracy than in the absolute accuracy. And this was much much easier. An was even possible for me with limited geographical knowledge because the GPS could sit just in one place ;-)
Thanks! it is a really nice video. I hope one day you could catch up with all your videos. I just started and there is alot to see. :D
use the visualgps software displays position accuracy
using google search
I used a similar software from ublox, the suplier of the GPS chips. It is also free.
u-center displays a littlbe different, different point of view
especially in height GPS is very weak at height measuring (ie geoid... bla bla)
visualgps and u-center provides different data, you might need both and another software for compare
Looks like you are testing an imitation ublox neo m8n. Did you check if it can receive Galileo? Did you check if it can be upgraded to version 3.01 using u-center software? If not then for sure this is an imitation! Performance of a real one is a lot better than those counterfeit models.
No, I did not check it.
Some quick checks to see if it is a genuine U-blox:
-Try to store settings from u-center. Try to change settings to power save mode as explained in a Ublox document (search for PowerManagement_AppNote_(UBX-13005162).pdf ). Go to the step by step guide in Chapter 3.1.1. Power save mode only work if you can disable Glonass. When you are done, disconnect from power supply and reconnect again. Now check if it is still on power save mode (and if Glonass is still disabled). Those counterfeit models usually have limited Flash memory so they immediately revert to 1 Hz full power.
-The next check would be to try to update to firmware V3.01. To do so, download this firmware from ublox and use u-center to upgrade (you have to select 2 files, the file you just downloaded and a second file that is on your hard disk in the windows ublox program directory. If it is a counterfeit model u-center will show a red screen with a message such as "no Flash detected"or "Flash timed out".
-Another thing to check is the GNSS system configuration page (in u-center). It probably shows just 32 channels available (the real Neo M8N is capable of receiving up to 72 channels).
Andreas, I am not receiving any satellites, there are a lot of “green” satellites on your module, but for me there is only one, red satellite. What is the problem here?
Maybe you have to wait till the database is downloaded
Andreas Spiess What database?
The database for the satellite data in the GPS chip.
Andreas Spiess how long will that take? What can I do?
You can just wait for half an hour or so.
I would like to see a comparison of these next to some smaller ones, I am interested in how much the size matters.
How about you show us the smallest GPS antenna you can find?
Antenna tests are very complex because the results depend on many things like place, clouds, etc. So du not expect it on this channel.
@@AndreasSpiess Well, I guess you're right.
Good video anyways!
Wait, the Neo-M6 can only pick up US sattelites? Maybe THAT'S why I can't get it to work in Sweden :D Will the M7 and M8 work though?
If your device does not work I would try it with the UBLOX software. It shows which satellites are currently visible and detectable by the module.
Andreas Spiess I only saw US flags next to the sattelites in UCenter, but they would appear for less than a second then dissapear. I am not able to try it close to a window yet. Will have to Create a ten meter data cord for that.
old video, i know... but aren't altitude sensors based on pressure effected by atmospheric weather air pressure, thus the altitude reading will change based on the weather...
Yes, you are right. This is why they are "calibrated" to a known altitude from time to time.
hi, good night from turkey. I need this card's eagle files. İf you have got this, can u share with me?
I do not have eagle files.
@@AndreasSpiess Ok. thanks for your reply
BeiDou will not work in Europe (according to wiki): "Unlike the American GPS, Russian GLONASS, and European Galileo systems, which use medium Earth orbit satellites, BeiDou-1 uses satellites in geostationary orbit. This means that the system does not require a large constellation of satellites, but it also limits the coverage to areas on Earth where the satellites are visible.[11] The area that can be serviced is from longitude 70°E to 140°E and from latitude 5°N to 55°N. A frequency of the system is 2491.75 MHz."
Thank you for this explanation.
That sounds like a really poor choice of frequencies and trying to filter out all the trash just below it on the 2400 MHz ISM band (Wifi, Bluetooth, microwave ovens etc.) I remember back in 2011 President Obama was going to open up a band for LightSquared for a cellphone band and then had to nix the idea because of potential interference to GPS.
BeiDou now includes at least 9 MEO satellites in its constellations, and should be able to provide worldwide coverage. en.wikipedia.org/wiki/BeiDou_Navigation_Satellite_System
Isn't this just a property of positioning systems? If more precise they can be used for targeting systems, what you don't want.
There are some differences between the chips, and also which satellites they can track.
Super Sach!
Merci viu mau. Mau luege obi dr Ungerschid vom M8N zum 6M im Quadcopter merke
+Simon Schödler Ich hatte eine leicht andere Zielsetzung, aber der 8er sollte auch im Quadcopter bei schwierigen Verhältnissen bessere Resultate geben, weil er mehr Sateliten "sieht". Kannst dich ja mal melden, wenn du es versucht hast. Bin gespannt.
Hoi wie gohts?
Find dini Videos echt guet!!!
Danke!
The accuracy of a GPS system highly depends on the amount of satellites received and the position of those satellites. For example. If you place the GPS antenna between some buildings and you have a narrow field of view (do not see much sky) the receiver will receive less satellites and the satellites which are received are all around the same position. That means that triangulation will have a big error. Height measuring with a gps will always have a lot of error. The best is to average the height over a long time and calibrate a pressure sensor with it. The pressure sensor will have good short term measurements but bad long term measurements. If the air pressure changes the reading will change a lot. So for the best system you will need both gps and air pressure. That is commonly used in drones for height measurement.
You can get a measure of accuracy for the GPS by looking at the HDOP, VDOP, PDOP and TDOP (Dilution of Precision) measurements which are in the EMEA string you get from the receiver. The higher those values the less accurate the readings are.
en.wikipedia.org/wiki/Dilution_of_precision_(navigation)
+Joost B You are absolutely right for general purpose systems. Because I wanted to build a power meter I was only interested in the difference in height, but very precise.
Very useful. Thankyou.
Looks like I'll be using a barometric sensor for relative altitude - my altitude changes are in no way going to be more than a few metres for what I want from the GPS. *then* I need to work on magnetometer (compass) and gyro/accelerometer to use as a clinometer.
.... and all because I want to be able to track where I've wandered on the moors.
Cyclometers also use a barometer because cyclists want to know the exact altitude they climbed ;-)
Does neo 6m and m8n share the same library?
I do not know. But you should find the info in the library description.
expecting more from you later!!
?
In 6M, What does M stands for ?
I do not know
for the BME280. I forgot to mention.
I never used the BME280 with the ESP8266. But all the commands are exactly the same. So, you should be able to use all Arduino libraries and sketches. Maybe you consult also the data sheet of the chip.
I found this video useful and interesting, especially the discussion of the different NMEA strings output by the NEO-6 and NEO-8 receivers. However, I would like to offer what I hope will be taken as constructive criticism.
I would suggest that instead of using the word "precision" to characterize the results, that "stability" or "repeatability" be used instead. In my view, precision is synonymous with resolution: if the device can measure a distance to a resolution of 1 cm, it's more precise than a device that can only measure distance to a resolution of 1 m. If one knows the correct value of a parameter, such as horizontal position in terms of latitude and longitude or elevation/altitude in terms of meters, a device that measures the same parameter with a constant offset of 1 m is more accurate than one that measures the parameter with a constant offset of 10 m. If a device consistently reports the value of a measurement with a variation of only 10 cm over an interval, its measurement is more repeatable than one that reports the value of a measurement with a variation of 50 cm over the same interval. In this video, I got the impression that what was being discussed was repeatability, not accuracy or precision.
While the BMP280 may be more stable (its measurements more repeatable) over a measurement interval of, for example, 10 minutes, the elevation data it produces may be less accurate than the GPS elevation data if the atmospheric pressure is not the standard 1013.25 HPa (or 29.92 in. of Hg). One can attempt to correct the BMP280 elevation data using the altimeter setting measurements reported by a local airport. (Google "METAR").
I would also comment that if one does not make measurements of GPS (or GNSS) receivers using actual satellite signals (instead of simulated signals in a laboratory environment) at the same time and place, one is not really doing an apples-to-apples comparison, because the satellites that are in MEO orbit are constantly moving across the sky, and different satellite signals may be blocked either by an obstruction or because the satellites are below the horizon at different times.
Well, that's enough (you'll probably say MORE than enough) pedantry for one comment.
Oops, I see you used the BME280 instead of the BMP280, but the principles are the same.
One more comment, about high-resolution pressure sensors: I have tested a BMP180 inside my home on a windy day with all of the doors and windows closed, and observed a lot of short-term fluctuations of the measured pressure. But if I operate the pressure sensor in a sealed jar, the short-term fluctuations almost disappear. I used a Microduino setup consisting of the Microduino Core+, Motion, SD, and USBTTL modules for this purpose, powered via a short USB cable connected to an Anker PowerCore power bank on one end and the USBTTL module on the other end, so the entire setup fit inside a 16 oz. canning jar. My Microduino setup recorded the data to a .csv file on a microSD card, which I then imported into an Excel file on my laptop. I wouldn't be terribly surprised if the BMP180/280 device measurements fluctuate on a calm day in the presence of loud music with a lot of bass.
You are right with your definitions. My project at this time was a bicycle power meter and all values needed were relative. I also have no idea on how to measure the absolute precision of a GPS device because I have no reference and I am no geographer with the needed knowledge.
To adjust a pressure sensor is easy, even if you do not read the METAR. You just measure the current pressure and adjust it to your current level. Or, as I usually do, to zero. Then I get the height difference very precisely. METAR is important because pilots have no reference if they fly in the air from a different region. Therefore they need the absolute pressure on the ground. If you stay on the ground, your pressure sensor should read the "METAR" value.
Ok, I was thinking.."Wow, this guy is making me fall asleep". "But wait, he did a really nice test!"...hehheh...Thanks buddy. +trainboy64 does a real quick practical bootup with a naza lite with the stock DJI and the m8n.
+John Robertson Thanks for keeping awake! It is harder than I thought to speak to "nobody" and keep the voice interesting, especially in a foreign language. Maybe I will improve over time. Sure enough, I will never get a Dave Johnes ;-)
+Andreas Spiess Haha. You should hear a German (ok, I know you said youre swiss, but I dont know any) speak well - jorge sprave and his slingshot channel - and one who speaks low - rcschim - who rates and reviews multirotor gear. Jorge talks LOUD...and I think RC who is also named Andres...speaks so softly that I cant hear him over the noise of my PC cooling fan!!!
Try GPS RTK with your M8N and RTKLIB you should get under 1 meter relative accuracy between two receivers.
+shodanxx Seems to be an interesting technology. But the effort is bigger than just using a GPS module. Did you try it? For me, it would be interesting to use it with a GSM module.
I got a pair of ublox m8n, still waiting on active marine gps antenna from ebay.
It's in the pipeline
A hobby level receiver can have RTK or did you mean position optimization thru post-processing?
Very informative. I'm looking at gps systems but can't make up my mind if I should spend $100 or spend $30 on this Neo-M8N
What is the 100$ alternative?
Oops not 100. Can you look at this micro Neo-M8N and tell me if it has the same capabilities as Neo-M8N. My Quad is really heavy and I think this will be better because it might work the same as the full size version.
www.readytoflyquads.com/micro-ublox-m8n-gps-w-18x18x
Considering this unit right now. Did you end up using it? Is it as good as the others?
The conditions of your test were not the same: different satellites and a different spread of the satellites around the sky.
You should compare them by using them at the same time and place.
You are right.
What about V.KEL VK2828U7G5LF ? :)
I never updated the comparison. But I think, the system itself creates a big deal of the errors, not the chips.
I saw a lot of reviews on Banggood for V.KEL (there are 247) and almost all are good but of course nothing like your reviews. You might try the 3 modules on something at high speed (like car ) and check how they behave (accuracy of speed and position). I'm sure many people will like it because of the soo many drone builders and some fly electric model planes to 100km and BACK :)
correct me if I'm wrong BUT you are only comparing the precision of each component's data stream and NOT the accuracy of each device. What I think you need to do is to check your precise location with respect to a known government geo survey point AND then compare the sensor data to that. For example I've previously in Australia looked as the position of a known official survey point with what Google Earth shows & GE is out with comparison to the official survey point.
+Ray Bright Yes, you are right. I only compare one part of precision. For my application, I am not interested in absolute precision compared with other maps. I only want to use it for my bycicle computer.
Still my tests are relevant also for your application, because the relative errors measured in my test add up to the errors compared with an absolute map.
I think also, it would be extremely complicated to make your comparison, because you are never sure if the error comes from the GPS or from the map. And here I definitively have no know-how as an engineer. I think, this is stuff for geometers ;-)
Funciona casi igual como el VK2828U7G5LF configurado para 5Hz
Thanks for your feedback.
I didn't understand if you said accuracy was withing 6 to 10 centimeters or 6 to 10 meters. If you said meters then accuracy in regard to the GPS sensors is an oxymoron.
With GPS it is always meters
Too many variables effect accuracy of measurements.
I think the biggest limiting factor is amount of digits after comma in these calculations. You need to use doubles instead of floats....
It's time to make a review of ZED-F9P ? :)
They seem to be very expensive...
With the antenna for my 6M module sitting in a window the altitude varies from 470 to 481 Meters! That's not very good precision!
I think, this is not very different from my findings.
Could I have your mail?
I can't do it with NEO M8N
+Tran Phat Can you please be more specific about your problem?
+Andreas Spiess, It's still ***** or Check your wiring. I understand what are you talking in this but It's not working with NEO M8N.
+Andreas Spiess oop! GPS NEO M8N default baud rate is 9600. And I change the code to
static const uint32_t GPSBaud = 9600;. It's working :D
Go to options>playback speed>select1.5
Thank me later
lol xD
Good video, I recently compared an Antaris 4 (uBlox 4) vs M8N (uBlox 8) and didn't find any improvement either in terms of accuracy for a static test. It will be much better for navigation in urban environments with lots of blocked signals where the use of additional GNSS systems helps a lot.
Thank you for sharing the results of your tests!
@@AndreasSpiess Sure, another test result that may be of interest. Using the uBlox 8 (8030 module) I have not seen any improvement with SBAS for horizontal accuracy, which is about 3.5 meters using the 2DRMS method but it improves vertical accuracy significantly from around 6.5 meters to 4 meters.
With RTK or PPK the uBlox 8 can be extraordinarily accurate, around 1 centimeter horizontal and vertical !
Hier ist ein Typ mit Schweizer Akzent
!
Vielen Dank!!!
Grüezi!
@@AndreasSpiess : Ich habe 2018 in Kehrsaz Nord gelebt
In der Nähe von Belp in Bern!
Hoi Andreas,
a nice comparison, but unfortunately you forgot to include one most important parameter for GPS precision, the DOP (dilution of precision). The DOP is a measurement of the current arrangement (or distribution) of the satellites on the sky. Similar to the issue in triangulation, the further the satellites are apart from each other, the better (or more precise) the reading.
In short, it's not just the NUMBER of satellites that helps for the precision (horizontal and equally vertical) but also how far apart they are from each other. 9 satellites more or less in the same direction from the GPS unit may result in worse precision (and more variation in the reading) than e.g. 5 satellites distributed over the whole firmament.
Pascal Fust You are right. I did not mention the DOP because I did not know its name. At 4:50 I mentioned, that the time gave the bigger differences than the devices. I assume, that the right word would have been DOP. But both somehow correlate, I assume.
BTW: Do the sensors know this parameter? Otherwise, how could we use it?
Yes, you're right, depending of the time in the day, the DOP changes. The sensor does actually get this data (horizontal and vertical DOP) from the satellites and you can also find them displayed in the Ublox center, as the user manual states.
+Pascal Fust Thanks!
Gärn gscheh
Pascal Fust :-)
Stationery GPS is not so accurate, when moving the precision gets better.
Multipath, Selective Availability and ionospheric effects is important to pecision, Multipath is problematic when stationery .
In your article, I did not find any information about stationary/mobile usage, it just says, if you have obstacles or reflective points close to your antenna, the performance is reduced.
Fortunately GPS is mainly used while in move ^^
Humm ... "open field precision" interessiert. Die messung von hauswandreflektionen interessiert weniger.
Für absolute höhenmessungen empfehle ich "sensor fusion" zwischen gps und bme280. Gps tiefpassfiltern plus bme280 hochpassfiltern. Das machen drohnen mit gyro und accel sensor auch so, gyro integriert mit hochpass pluss accel mit lowpass. Jeder sensor macht das wass er gut kann.
Gute Idee.