main.c

GPS导航定位程序

#include "includes.h"

/****************************************************************************    
* Function: void main(void)
*
* The program entry point. Termination occurs by either uses a call to exit
* to exit (before the environment has been altered) or to QuitGpsBuilder 
* (which restores the PC environment to the pre-existing state).               
*
* Input: None.
*
* Output: None.
*
* Return Value: None.
****************************************************************************/
void main(void)
{
    MStkSS = _SS;                             /* Store the stack pointers. */
    MStkSP = MStkHwm = _SP;
    GpsBuilder2();                               /* Call the main routine. */
}

/****************************************************************************    
* Function: void GpsBuilder2(void)
*
* Initialize the GPS Builder-2 hardware and software, then initiate   
* multitasking and run the program until it is terminated.              
*
* Input: None.
*
* Output: None.
*
* Return Value: None.
****************************************************************************/
void GpsBuilder2(void)
{
    int CurrentPredictSV;     /* The SV number for which predict are made. */
    int highest[MAXCHANNELS];          /* Satellites ordered by elevation. */

    Checkpoint("GpsBuilder2",1);
    SuppressCursor();

    Checkpoint("GpsBuilder2",2);
    ClearScreen();

    Checkpoint("GpsBuilder2",3);
    SetFPErrorHandler();

    Checkpoint("GpsBuilder2",4);
    SetUpCorrelators();

    Checkpoint("GpsBuilder2",5);
    ConfigureInterrupt();

    Checkpoint("GpsBuilder2",6);
    TestingInterface = TRUE;
    HardwareTest();
    TestingInterface = FALSE;

    Checkpoint("GpsBuilder2",7);
    InstallControlBreakHandler();
    if(setjmp(cbrkjmp))
	QuitGpsBuilder();  /* Terminate gracefully */

    Checkpoint("GpsBuilder2",8);
    AllocateMemory();
    
    Checkpoint("GpsBuilder2",9);
    InitialiseTasks();

    Checkpoint("GpsBuilder2",10);
    InitialiseGP2021();         

    Checkpoint("GpsBuilder2",11);
    SetUpGlobals();

    Checkpoint("GpsBuilder2",12);
    SetClockModel();

    Checkpoint("GpsBuilder2",13);
    ReadAlmanacs();

    printf("\n\nPlease Wait - Initialising System....");
    printf("\nInitialisation Time Is Dependent Upon PC Speed.\n");
    printf("\n***** WARNING *****");
    printf("\nIf you can still read this message then it is likely that "
	   "your PC is too slow\nto support the number of channels currently "
	   "active. Try adjusting the channel\nnumber (CH x) in CMD.INI "
	   "starting from 3 and incrementing by 1 each time.\n\n\n");
    
    Checkpoint("GpsBuilder2",14);
    PredictAll();                       /* Do predicts for all satellites. */
  
    Checkpoint("GpsBuilder2",15);
    DisplayFunc=3;
    Activate("TDisplay");

    Checkpoint("GpsBuilder2",16);
    ProcessCommandFile();           /* Process commands from CMD.INI file. */

    /* Since some misses can occur during initialization */ 

    misso = missa = missm = 0;

    CurrentPredictSV = 0;

    /* Initialization is complete. Start multitasking and begin normal
       operation. */

    PROTECT = 0;

    for(;;)
    {
	Keyboard();

	Checkpoint("GpsBuilder2",17);
	ValidateEphemerides();

	/* Predicts are done for only 1 satellite per iteration of this
	   loop to reduce loading. */

	Checkpoint("GpsBuilder2",18);
	CurrentPredictSV++;
	if(CurrentPredictSV>MAXSATELLITES)
	    CurrentPredictSV = 1;
	AzimuthElevationAndDoppler(CurrentPredictSV-1);

	Checkpoint("GpsBuilder2",19);
	OscillatorAccuracy();                   /* Update the clock model. */

	Checkpoint("GpsBuilder2",20);
	NumberOfDopplerBins();      /* Get the new number of Doppler bins. */

	Checkpoint("GpsBuilder2",21);
	ElevationList(highest);          /* Order satellites by elevation. */

	Checkpoint("GpsBuilder2",22);
	UpdateSatelliteAllocation(highest);   /* Update according to Mode. */

	Checkpoint("GpsBuilder2",23);
	UpdateNavigation();                  /* Do navigation if possible. */

	/* If a data logging file is open, or COM1 output is active, and the 
	   log interval is non-zero then go to the save data routine. */

	Checkpoint("GpsBuilder2",24);
	if((fpDataLog!=NULL || DataLogSerial==TRUE) && DataLogInterval!=0)
	    SaveData();
    }
}