The Iliad - Book I

[PaulZC]

Note: this PR needs the latest version of SEMP (1.0.6) and the UM980 library (1.0.10)

This PR:

• Attempts to minimise the "no increase in file size" and the disconnect "due to lack of RTCM" glitches during NTRIP Server

• See [Release Candidate] NTRIP Server breaking connection due to (unreal) lack of RTCM #702 for details. The real issue is network latency when using rtk2go. But there are improvements that can be made:

• RTCM data from the GNSS is stored in a new ring buffer in PSRAM

  • See Base.ino for details

• Data is written to consumers by sendRTCMToConsumers() - from inside the gnssReadTask instead of processUart1Message

• On WiFi / Ethernet / Cellular: each complete RTCM message is written in one single write

  • Previously RTCM was written a byte at a time - which slowed things down dramatically!

• Moves NTRIP_SERVER_DATA from settings.h into NtripServer.ino

• Adds more semaphore-protected methods in NTRIP_SERVER_DATA to prevent connected() checks during a write()

• Adds pin_debug for logic analyzer debugging - on EVK we can use the baseStatusLED for this

• Adds settings.networkClientWriteTimeout_ms to avoid excessive write times from the default 3000ms timeout

• Reverts the recent increase in uartReceiveBufferSize and btReadTaskStackSize

• Adds new Tools Dinger.py and NTRIP_Sink.py

  • Dinger.py examines COM data, looks for a string and generates a "Ding" when the string is found. The date, time and following data are printed too. Very handy for trapping and recording rare events
  • NTRIP_Sink.py is a very simple local NTRIP Server: when a device connects, it sends "ICY 200 OK" and then sinks all incoming data with a byte count. Very handy for testing NTRIP Server without the latency of an external Caster

• Allows individual NTRIP Servers to be Enabled / Disabled - as requested in Postal RTK: In Base mode, turn casters on or off individually. #758

• Includes a temporary workaround to prevent bluetoothStop() from crashing

• Adds BaseAssist - as requested in [Feature Request] Add "Base Assisted" Mode #751

  • It is now possible to go from Rover (with RTK Fix) into Fixed Base mode - using the position of the RTK Fix
  • It is also possible to go from Base (Survey-In) into Fixed Base mode - using the surveyed-in position

• This required some tweaks to the RTK_MODE

  • There is a new RTK_MODE RTK_MODE_BASE_UNDECIDED which prevents NTRIP Client from starting and immediately stopping
  • Previously NTRIP Client would start when Base (Survey-In) was selected and then immediately stopped when Fixed Base began. I was seeing the firmware hang in a state where NTRIP Client had stopped, NTRIP Server had started, WiFi remained enabled, but there was no 'kick' to make NTRIP Server actually connect to the Caster. Adding RTK_MODE_BASE_UNDECIDED fixes this.

• Adds a fix for the Geoidal Separation issue in Inconsistency in GNSS getAltitude #809

  • Previously getAltitude would: for two GNSS report Height above MSL; for the other two report Height above Ellipsoid
  • This fix makes all four GNSS consistent; height above ellipsoid is always reported by getAltitude
  • Requires UM980 Library 1.0.10 - released today

[nseidle]

Next time, more discrete PRs please. Overall, looks very good.