Tracked signals and number of channels


I’ve been working with GNSS for a long time, and now, analyzing and studying better new alternatives for equipment and systems, I had some doubts about the number of channels and signals tracked by GNSS:

  1. How many channels will determine how many signals the receiver will track from each satellite/constellation?

  2. M2 tracks 2 signals from each constellation (GPS, QZSS, GLONASS, BeiDou, Galileo) ie 5 constellations with 2 signals each, does it mean that each satellite will use two channels?

  3. Is the 184-channel M2 able to track 92 satellites?

  4. Does the nomenclature of signs change according to manufacturers? For example: GLONASS L1OF equals GLONASS L1 only?

  5. Does the C/A code use separate channel?

Sorry for my ignorance about this. But I had never really stopped to understand how channels and signals work.

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Hi mauricioranzan

I can help you with some answer,

One channel is for one signal, example:
GPS system have 4 signal L1C/A, L1C, L2C y L5
then for you track the 4 signal, need 4 channels only for one satellite, If you track 4 GPS satellites you have been 16/184 channels.
I have a video, that can be more didactic

If you see in GPS Horizon 40 satellites and everyone transmits 4 signal, you use 4*40=160 channels. Maybe you can answer the #1,# 2 & # 3 questions with this information.

In respect to the question #4 I don’t know.

The question #5. The Signal L1, in your structure combine, mix and Encrypt different information. You can see this in the Image example to L1.

In summarize, Channel is the number of signal
which the receiver can obtain from different satellite.


Hello, @bernardo.barraza
Good morning here,
How are you?

Thank you very much for the information.
I understood everything.
Very well placed.
And the video, very didactic.

Big hug.

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Hi @mauricioranzan,

Bernardo has already posted a thorough answer to most of your questions, so I just want to share a couple of additional tips :slight_smile:

The signal’s name includes the transmission frequency and some info about the signal. For instance, GLONASS L1OF means the FDMA Open Service Navigation Signal received at the L1 frequency band. From my knowledge, GLONASS L1OF/L2OF are usually referred to as L1/L2, as these are the open standard-precision signals. However, you can check the exact list of supported signals with the particular manufacturer.

Here’s the list of signals Reach M2 receives, just in case:



  • BeiDou B1I, B2I

  • Galileo E1-B/C, E5b signals

Reach M2 typically uses 2 channels for each satellite. Actually, not every satellite provides L2C data, so the receiver can track more than 92 satellites at the same time. In most cases, GNSS receivers see around 40 satellites even with the clear sky view, so that’s more than enough to handle all of them.


Does the f9p chip also track l1c (mboc?)?

Hello @kseniia.suzdaltseva
I think I got it all right.

I have noticed that my system here ranges from +30 to 42 satellites.
42 was the maximum I’ve visualized so far.
And I was happy too, because with a GNSS that I had before I didn’t even reach 20.

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Hi Christian,

That’s an interesting question! In the F9P specs, only L1 C/A is mentioned. Nevertheless, I’ll double-check it with the team.

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Indeed, it is just wierd that the chip would read GpS L2C and even Gal L1C, which should be the same type of signal as GPS L1C.

Hi Christian,

It looks like L1C is indeed not supported by F9P. There are some differences between GPS L1C and GALILEO E1 specs, such as the power distribution between the channels, channel code, symbol rate, etc. So, even if one of the signals is already supported, another one can require additional implementation.

GPS L1C won’t be fully launched in the nearest future, so the lack of this signal doesn’t make any difference in the calculations. Also, GPS satellites will continue broadcasting L1 C/A signals at the same frequency even when L1C comes into play. So, GNSS receivers will be able to continue using them.


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