Sirf payload to transport message converter

sirfmsg.pl

#!/usr/bin/perl
use strict;

#Encapsualtes hex payload into SiRF binary transport message
#Example: sirfmsg.pl a600020500000000

my $payload = pack("H*", $ARGV[0]);
my $csum = 0;
my $payload_length = map { $csum = ($csum + $_) & 0x7ff  } unpack("C*", $payload);

print STDOUT
   pack("nn", 0xa0a2, $payload_length),
   $payload,
   pack("nn", $csum, 0xb0b3);