Example Interface for Obtaining Range-Rate Information from InstantTrack OrbitDRV

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RRdemo is a programming example showing how to obtain range-rate information (that is, rate of change of the range, which is proportional to Doppler shift) from the OrbitDRV TSR component of InstantTrack. It consists of one C file, a corresponding .h header file, and a tiny assembly language glue file. The C file can be used as-is in an application, or it can be compiled with the symbol MAIN defined to produce the standalone demo program RRdemo.

RRdemo is a command-line program. Programs built with this interface file included must run in TTY mode during initialization, but need not stay in that mode during operation.

System Requirements

To run the included executable, an environment capable of running InstantTrack is required. See InstantTrack's system requirements.

To compile the module without modifications, you'll need Microsoft C 6.00A and Microsoft MASM 5.1. Other C compilers and assemblers capable of building a DOS TSR can probably also be used with some changes.




This example shows compiling the demo program in the C:\tmp directory, then switching to the InstantTrack directory, installing the usual TSRs, initiating tracking of a satellite, and then running the demo program for a few seconds.

C:\tmp>cl -W3 -DMAIN -c orbitdrv.c
Microsoft (R) C Optimizing Compiler Version 6.00A
Copyright (c) Microsoft Corp 1984-1990. All rights reserved.           


C:\tmp>masm radiodrv;
Microsoft (R) Macro Assembler Version 5.10
Copyright (C) Microsoft Corp 1981, 1988.  All rights reserved.

  48316 Bytes symbol space free

      0 Warning Errors
      0 Severe  Errors

C:\tmp>link orbitdrv+radiodrv,rrdemo;

Microsoft (R) Segmented-Executable Linker  Version 5.10
Copyright (C) Microsoft Corp 1984-1990.  All rights reserved.

C:\tmp>cd \it



C:\IT>itrack ao-16

OrbitDRV interface installed OK.
Hit any key to exit.
Rangerate = 7.8002e-006
Az = 39, El = -60
Rangerate = 7.78311e-006
Az = 39, El = -60
Rangerate = 7.76601e-006
Az = 39, El = -60

Uninstalling OrbitDRV interface.


Current Status

Barely tested. It works for me. Please let me know if you use it and whether or not you have any problems with it.


Known Bugs



RRdemo is released under a derivative of the X11 license, a permissive (non-copyleft) open source license.

Source Code

Source code in C and assembly language is included. Being a DOS TSR, this is NOT portable code.


RRDEMO.TXT - user manual (plain text, 2K)


RRdemo (zip file, 22K)

Copyright 2002 Paul Williamson. Comments to kb5mu@amsat.org