Add u-blox M7 Power mode setting UBX_CFG_PMS

[stefanux2]

1. Stratux version: latest EU

2. Stratux config:

   SDR

   • [X] single
   • [ ] dual

   GPS

   • [X] yes
   • [ ] no type:

   AHRS

   • [X] 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]

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]

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: https://github.com/b3nn0/stratux/blob/0a5c01a5d8fae01e9062fa7bb7cc06ae82bd8b1a/main/gps.go#L569

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

[b3nn0]

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]

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.