Well firstly I fixed the issue with the lack of GPS signal. A miss read of the datasheet, the active aerial does need power imagine that. Anyway once I’d powered that up and provided power to pin2 on the ISM300 ( the battery circuit is “optional” but in the small print it says “you must hold pin 2 over 1.65v to function”. Todays lesson is always read the datasheets carefully again and again.
Once the GPS was giving location data a few hours coding on the Arduino was decrypting the NMEA string nicely. After a little erroneous mathematics the latitude and longditude are now converting into the correct format. One thing that threw me was when you Serial.print a float the default is it only does it to two decimal places. I thought I was loosing accuracy but the actual float does still contain the accuracy.
Once the telemetry information was working I copied in the temperature sensor code and constructed the UKHAS telemetry string :
$$AVA,1223,11:45:22,53.1111,1.2234,250,6,23,22*002A
Where
$$Call Sign,TICKER,UTC TIME,LATITUDE,LONGDITUDE,ALTITUDE,SATELLITES,TEMP INT,TEMP EXT CHECKSUM
Also made the LED blink when there is no GPS lock which is currently always as the active aerial doesn’t seem to be working again, dodgy wiring probably.
Need to get the NTX2 working now, on the plus side someone can loan me a radio to test it with!
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