[aprssig] APRS Calculator Program

[gerheim at cox.net]

Thanks to Bob Bruninga's _very_ patient help, the data parser is doing nicely.  

The intent is to improve the interface compared to the "bare" Kenwood D7.  This is for extremely portable (no PC) APRS operation.  

What I have in mind is a calculator program with 3 display modes.  

Monitor mode will show:
Own Station: position, course, speed, confirm digipeat ("MY POSITION")
Remote stations (10 or so): position, course speed, distance, azimuth. I'm not sure how to select the 10, or order them on the display.  

Drill-Down mode:
For a single remote station: position, course, speed, distance, azimuth, CPA time (if both stations are _not_ fixed), full message, and/or mic-e message.  

Transmission mode:
Set path, callsign (with ssid), message (no mic-e capability), and beacon parameters.  I'm not sure how big the message can be.  It might support the email-via-ariss option, if it's still in use.  

The arrow keys will be in user mode, and will permit interruption of Monitor or Drill-Down screens.  

The D7 will generate free-running beacon transmissions and present received data to the calculator.  The calculator will querry the GPS receiver (if attached) via the D7.  

The parser can now read standard text.  It _will_ read mic-e, plus GPGGA and GPRMC sentences.  

I can synchronize the calculator to GPS time, but I don't know how often you need to do it.  

Any comments?  Suggestions?  

I'd love to send the received station data to the GPS receiver, but my eTrex Legend only supports 1-way NMEA data.  

There's also a possibility I can write a Kalman FIlter routine to estimate course/speed from a sequence of position reports.  



--
-Al Gerheim

HP-49G+ Software Page:
http://members.cox.net/above