Rolling GPS latlong logging. Stores the latest 100 distinct latlong coordinates (redundant coordinates are ignored). Coordinates are stored in: /LOGS/GPS_rolling_positions.log. Logging is paused if less than 4 satellites are available.

GPSLog.lua

-- License https://www.gnu.org/licenses/gpl-3.0.en.html
-- OpenTX Lua script
-- FUNCTION
-- Place this file in SD Card > /SCRIPTS/FUNCTIONS/

-- Author: Elia P.

-- Date: 2019 November 02

-- Description
-- Rolling GPS latlong logging
-- Stores the latest 100 distinct latlong coordinates (redundant coordinates are ignored).
-- If the number of sats is smaller than 4 coordinates are not recorded.
-- requires GPS telemetry and SD Card

-- Set-iup:
-- Run the script every 2 seconds via a Logic Switch.
-- Create a timer Logic Switch with a duration of 0.1s and a pause 2s.

local NumCoordinatesToPersist = 100 

local function rnd(v,d)
  if d then
    return math.floor((v*10^d)+0.5)/(10^d)
  else
    return math.floor(v+0.5)
  end
end

local function getGPSLatLon()
  gpsLatLon = getValue("GPS")
  if (type(gpsLatLon) == "table") then
    return rnd(gpsLatLon["lat"],5) .. ", " .. rnd(gpsLatLon["lon"],5)
  else
    return "not currently available"
  end
end



local function init_func()

end


local function log_position(latlog,alt,sats)
  local logFile   = "/LOGS/GPS_rolling_positions.log"
  local logRead = io.open(logFile,"r")
  local previous_positions = ""
  if logRead ~= nil then
    -- every log entry is exactly 90chars
    previous_positions = io.read(logRead,90*(NumCoordinatesToPersist-1))
    previous_position = ""
    for match in string.gmatch(previous_positions, 'LatLong: +"([0-9 ,.-]+)"') do
      previous_position = match
      break
    end
    io.close(logRead)
  end
  if latlog == previous_position then
    return
  end
  local logWrite = io.open(logFile,'w')
    if logWrite ~= nil then
      io.write(logWrite,string.format("%-13s%-22s","LatLong:",'"'..latlog..'"'))
      io.write(logWrite,string.format("%13s%07d","Altitude:",alt))
      io.write(logWrite,string.format("%11s%02d","Sats:",sats))
      local now = getDateTime()
      io.write(logWrite,string.format("%21s", now.year.."-"..now.mon.."-"..now.day.." "..now.hour..":"..now.min..":"..now.sec))
      io.write(logWrite,"\n")
      io.write(logWrite,previous_positions)
      io.close(logWrite)
    end
end

local function run_func()
  latlog  = getGPSLatLon()
  alt  = getValue("Alt")
  sats = getValue("Sats")
  if sats > 3 then
    log_position(latlog,alt,sats)
  end
end

return { run=run_func, init=init_func }

GPSScr.lua

-- License https://www.gnu.org/licenses/gpl-3.0.en.html
-- OpenTX Lua script
-- TELEMETRY
-- Place this file in SD Card > /SCRIPTS/TELEMETRY/

-- Author: Elia P.

-- Date: 2019 November 02

-- Description
-- Rolling GPS latlong log Screen
-- To be used with the FUNCTION/GPSLog.lua script.
-- Display on the screen the last 5 logged GPS coordinate

local function init_func()

end

local function bg_func()
  -- Called periodically when screen is not visible
  -- This could be empty
  -- Place code here that would be executed even when the telemetry
  -- screen is not being displayed on the Tx
end

local TextHeader = "GPS LOG                           "

local function run_func(event)
  -- Called periodically when screen is visible
  
  local logFile   = "/LOGS/GPS_rolling_positions.log"
  local logRead = io.open(logFile,"r")
  
  lcd.clear()
  
  -- XXLSIZE, MIDSIZE, SMLSIZE, INVERS, BLINK
  lcd.drawText(1, 1, TextHeader, MIDSIZE + INVERS)
  local line = 16;
  if logRead ~= nil then
    -- every log entry is exactly 90chars, read 5 lines meaning 450 chars
    previous_positions = io.read(logRead,450)
    for match in string.gmatch(previous_positions, 'LatLong: +"([0-9 ,.-]+)"') do
      lcd.drawText(1, line, match,0)
      line = line + 10
    end
    io.close(logRead)
  end
end

return { run=run_func, background=bg_func, init=init_func  }

Thank you for this. Any luck in getting the export to CSV?