EM506 GPS Module With PHPoC Blue

<?php
include_once "/lib/sd_340.php";

$gps_cmd = _GET("gps");

$latitude = 0.0;
$longitude = 0.0;

if($gps_cmd == "read")
{
	uart_setup(0, 4800);

	$msg = "";
	
	while(1)
	{
		$rbuf = "";
		$read = uart_read(0, $rbuf);
		if($read > 0)
		{
			$msg .= $rbuf;
			if(strpos($msg, "\r\n") !== false)
			{
				$idx = strpos($msg, "\r\n");
				$cmd = substr($msg, 0, $idx);
			
				if(strpos($cmd, "$") !== false)
				{
					$idx = strpos($cmd, "$");
					if(($m_id = substr($cmd, $idx + 1, 5)) !== false)
					{
						if($idx > 0)
						{
							$cmd = substr($cmd, $idx);
						}
						if($m_id == "GPGGA")
						{
							$cmd_crc = str_replace("$", "", $cmd);
							$cmd_crc = str_replace("*", "", $cmd_crc);
						
							$crc = 0;
							$len = strlen($cmd_crc);
							for($i = 0;$i < $len - 2;$i++)
								$crc ^= bin2int($cmd_crc[$i], 0, 1);
								
							$str_crc = substr($cmd_crc, $len - 2);
						
							if(bin2int(hex2bin($str_crc), 0, 1) == $crc)
							{
								$arr = explode(",", $cmd);
							
								$latitude = (int)substr($arr[2], 0, 2) + (float)substr($arr[2], 2, 7) / 60;
								$longitude = (int)substr($arr[4], 0, 3) + (float)substr($arr[4], 3, 7) / 60;
								break;
							}
						}
					}
				}
				$msg = "";
			}
		}
	}
}

?>
<!DOCTYPE html>
<html>
  <head>
    <title>P4S-342</title>
  </head>
  <body align=center>
  	<a href="index.php?gps=read">Read GPS</a><br>
  	<?php
  		if($gps_cmd == "read")
  		{
  			printf("GPS - Latitude: N%.4f, Logitude: E%.4f<br><br>", $latitude, $longitude);
  			printf("<a href=http://maps.google.com/?q=%f,%f&hl=en target=_g_map>View in Google Map</a>", $latitude, $longitude);
		}
  	?>
  </body>
</html>