Is My PM200 in L1L2 or L1G1 mode?

If you have a PM200, you already know that the receiver will track L1/G1 or L1/L2. But not both.

If you are trying to record data to send to NGS for an OPUS solution, you need (have) to track L1/L2.

Here are my suggestions:

1. There is an interaction between FAST Survey and the GNSS Toolbox. In FAST Survey, under ‘Equip: GPS Rover: Receiver” press the ‘Advanced’ button. UNCHECK use GLONASS. 

2. Before you start to record raw data, make sure you are tracking L1 and L2. You can do this by going to the “Equip: Monitor Skyplot” screen. If the receiver is tracking L1/L2 you will see split signal strength bars for each SV. And you won’t see and GLONASS SV’s tracked on the bottom line.

Here is what this should look like when you are tracking L1 / L2:

Image(sorry about the crappy picture) You can see each signal strength bar is split, the left is L1 S and the right is L2 S.

This is also obvious from the GNSS Toolbox:



Again, each of the blue bars is split into two pieces.

Conclusion: If you are recording data to submit to OPUS and you don’t see the split bars, you have done something wrong. You need to select L1/L2 from the GNSS Toolbox AND you need to uncheck GLONASS in FAST Survey.




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4 responses to “Is My PM200 in L1L2 or L1G1 mode?

  1. Talal Rashed

    Is this same with PM500?

    • We have a question about the PM 220 and the OPUS solution. We just upgraded from using 2 PM 100′s to having one with PM 220. It appears we can either run a static file and correct off of the OPUS solution or use the Oregon network (ORGN) with our cell signal. Which would you suggest? We tried the ORGN network and it seems to work fine, however we are having some fits in terms of expressing the vertical datum in NAVD 88.
      Lower Columbia Estuary Partnership

    • I would use the RealTime network, where it will work. If you have a point that needs high precision, I would also do a 4-hour (or more) OPUS shot.

      You should be able to match Orthometric elevations well. Make sure you are using the latest 2012A geoid. If there is a constant offset, check/double-check your HI’s. Finally, if that does not resolve you may want to crank in an offset.

      However, I would not use an offset until I had a 4-hour OPUS solution over a HARN point in hand so I could determine what the correct result might be.

  2. Thanks so much…..a couple quick follow-up questions:
    1) how would you define a “high precision” point? We are looking at basically trying to get cm accuracy for Water surface levels…we can look at PDOP and HMRS and VRMS.
    2) So far, we are only showing Ortho. heights in negative values in the field (i.e. not converted to NAVD 88) on our Promark 220. The only way were are able to get to NAVD 88 is by using GNSS Solutions and post-processing…..something seems off about that. It strikes me that we should be getting NAVD 88 elevations off of the ORGN real time network. Note- we are still using Geoids 09.
    ~ Many thanks, Paul

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