Two similar modules GPS, different precision

Using Arduino Sensors
1

Hi. I have two modules, one is: Ublox NEO-M8Q the second Quectel l76.

On ublox, the maximum number of satellites in a fix is 12 on quectel 17, both of them default to GPS + GLONASS + SBAS. Why such differences in the number of satellites? As a curiosity, I will give ublox with fewer satellites and more precision. What could be the reasons. What are your experiences? Thanks for the answer!

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The number of receiver channels sets one limit on the number of satellites. You may find this discussion useful: How many GPS channels make sense? - Electrical Engineering Stack Exchange

The actual number seen will vary with time of day, weather, location and nearby obstructions.

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Yes, but often fewer satellites give me more precision ... Question why is this happening?

4

Better firmware.

5

Hi,
Different aerial patterns?
Can you please post pictures of both the GPS units?

Thanks.. Tom... :smiley: :+1: :coffee: :australia:

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When you say 'precision' do you really mean that or are you confusing it with accuracy ?

To show that fewer satellites give you greater position accuracy on average you would need to run the GPS for a while, 24 hours maybe, to see what the average position variation actually is.

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So I mean accuracy at the moment. In general, on Ublox I had a maximum of 12 satellites, on Quectel I sometimes have 20, comparing the manuals of the WAS and SBAS memory systems are enabled by default on both. Why are there such big differences in the number of satellites between these modules?

8

Different manufacturers, different receivers, different firmware.

1 Like
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I noticed that the l76 manual mentions 12 basic satellites, so what are the additional ones? Is it possible to activate any satellite limit? I noticed that those that he finds the fastest, e.g. 10-14 when I mark the items, I come back to them perfectly, while when I find more, it shows me the designated point 2-4 meters elsewhere.

10

Hi,
Not sure but this may help.
https://wiki.openstreetmap.org/wiki/Test_the_accuracy_of_GPS_devices

Have you been able to view the HDOP value from each GPS?

Tom... :smiley: :+1: :coffee: :australia:

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