b3nn0/stratux

Add u-blox M7 Power mode setting UBX_CFG_PMS

Closed this issue · 4 comments

stefanux2 commented

  1. Stratux version: latest EU

  2. Stratux config:

    SDR

    • single
    • dual

    GPS

    • yes
    • no
      type:

    AHRS

    • yes
    • no

    power source: USB

    usb cable: +5V

  3. EFB app and version: Easy VFR

    EFB platform: iOS Latest

    EFB hardware: iPad Mini

  4. Description of your issue:

The request is to add the settings for UBX_CFG_PMS to switch between Default Power or Full Power.
The stratux set Full Power but on certain models of USB VK-162 the best is to keep it as "default" power.

Proposed solution:

  • Add the management interface setting html
  • Add the parameter to management interface
  • Add default configuration to Full Power
  • Add into gps interface the switch

Proposal source code will be posted by merge request during next days.

b3nn0 commented

Not sure I am a fan of it. It is a setting that 99.9% of users will not understand and shouldn't touch anyway. We should find a reasonable default that works. What gave you the idea that it should be changed? Can you elaborate a bit?

stefanux2 commented

Not sure I am a fan of it. It is a setting that 99.9% of users will not understand and shouldn't touch anyway. We should find a reasonable default that works. What gave you the idea that it should be changed? Can you elaborate a bit?

After building many stratux with VK-162 USB dongle and testing them I noticed that commenting this line the time to fix and performance is much improved:

stratux/main/gps.go

Line 569 in 0a5c01a

p.Write(makeUBXCFG(0x06, 0x86, 8, []byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})) // Full Power Mode

I suspect that this kind of M7 works better with default UBX_CFG_PMS

b3nn0 commented

Surprising... But if that's really reproducible, than do that for all Ublox 7, not as a setting. I will conduct some tests tomorrow, too.

b3nn0 commented

Just did some tests with an M8N.
Testing methodology:

  • Plug GPS in, start Stratux process to get our basic configuration on it, and wait for a fix, just so things are warmed up.
  • Stop Stratux and connect via U-Center
  • Trigger "Coldstart" and measure time to first fix to collect samples
  • After 5 samples collected, switch to "Balanced Mode" and collect again

Result samples(seconds):
Full power
47
47
88
59
53
-> Median: 53, AVG: 58,8

Balanced
51
54
50
53
30
-> Median: 51, AVG: 47,6

Admittedly, the sample size is not big, but I think we can safely say, that "Full Power" mode at least doesn't significantly improve anything.

Conclusion: We remove this setting entirely and use the default, assuming that the UBlox engineers know what they are doing.