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rtl_adsb: prototype

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Signed-off-by: Steve Markgraf <steve@steve-m.de>
master
Kyle Keen 12 years ago committed by Steve Markgraf
parent d6107bb059
commit 562fd7e8e3
3 changed files with 475 additions and 2 deletions
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  1. 9
      src/CMakeLists.txt
  2. 5
      src/Makefile.am
  3. 463
      src/rtl_adsb.c

9
src/CMakeLists.txt
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@ -71,7 +71,8 @@ add_executable(rtl_tcp rtl_tcp.c)
add_executable(rtl_test rtl_test.c)
add_executable(rtl_fm rtl_fm.c)
add_executable(rtl_eeprom rtl_eeprom.c)
set(INSTALL_TARGETS rtlsdr_shared rtlsdr_static rtl_sdr rtl_tcp rtl_test rtl_fm rtl_eeprom)
add_executable(rtl_adsb rtl_adsb.c)
set(INSTALL_TARGETS rtlsdr_shared rtlsdr_static rtl_sdr rtl_tcp rtl_test rtl_fm rtl_eeprom rtl_adsb)
target_link_libraries(rtl_sdr rtlsdr_shared
${LIBUSB_LIBRARIES}
@ -93,6 +94,10 @@ target_link_libraries(rtl_eeprom rtlsdr_shared
${LIBUSB_LIBRARIES}
${CMAKE_THREAD_LIBS_INIT}
)
target_link_libraries(rtl_adsb rtlsdr_shared
${LIBUSB_LIBRARIES}
${CMAKE_THREAD_LIBS_INIT}
)
if(UNIX)
target_link_libraries(rtl_fm m)
if(APPLE)
@ -108,11 +113,13 @@ target_link_libraries(rtl_tcp libgetopt_static)
target_link_libraries(rtl_test libgetopt_static)
target_link_libraries(rtl_fm libgetopt_static)
target_link_libraries(rtl_eeprom libgetopt_static)
target_link_libraries(rtl_adsb libgetopt_static)
set_property(TARGET rtl_sdr APPEND PROPERTY COMPILE_DEFINITIONS "rtlsdr_STATIC" )
set_property(TARGET rtl_tcp APPEND PROPERTY COMPILE_DEFINITIONS "rtlsdr_STATIC" )
set_property(TARGET rtl_test APPEND PROPERTY COMPILE_DEFINITIONS "rtlsdr_STATIC" )
set_property(TARGET rtl_fm APPEND PROPERTY COMPILE_DEFINITIONS "rtlsdr_STATIC" )
set_property(TARGET rtl_eeprom APPEND PROPERTY COMPILE_DEFINITIONS "rtlsdr_STATIC" )
set_property(TARGET rtl_adsb APPEND PROPERTY COMPILE_DEFINITIONS "rtlsdr_STATIC" )
endif()
########################################################################
# Install built library files & utilities

5
src/Makefile.am
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@ -10,7 +10,7 @@ lib_LTLIBRARIES = librtlsdr.la
librtlsdr_la_SOURCES = librtlsdr.c tuner_e4k.c tuner_fc0012.c tuner_fc0013.c tuner_fc2580.c tuner_r820t.c
librtlsdr_la_LDFLAGS = -version-info $(LIBVERSION)
bin_PROGRAMS = rtl_sdr rtl_tcp rtl_test rtl_fm rtl_eeprom
bin_PROGRAMS = rtl_sdr rtl_tcp rtl_test rtl_fm rtl_eeprom rtl_adsb
rtl_sdr_SOURCES = rtl_sdr.c
rtl_sdr_LDADD = librtlsdr.la
@ -26,3 +26,6 @@ rtl_fm_LDADD = librtlsdr.la $(LIBM)
rtl_eeprom_SOURCES = rtl_eeprom.c
rtl_eeprom_LDADD = librtlsdr.la $(LIBM)
rtl_adsb_SOURCES = rtl_adsb.c
rtl_adsb_LDADD = librtlsdr.la

463
src/rtl_adsb.c
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@ -0,0 +1,463 @@
/*
* rtl-sdr, turns your Realtek RTL2832 based DVB dongle into a SDR receiver
* Copyright (C) 2012 by Steve Markgraf <steve@steve-m.de>
* Copyright (C) 2012 by Hoernchen <la@tfc-server.de>
* Copyright (C) 2012 by Kyle Keen <keenerd@gmail.com>
* Copyright (C) 2012 by Youssef Touil <youssef@sdrsharp.com>
* Copyright (C) 2012 by Ian Gilmour <ian@sdrsharp.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#ifndef _WIN32
#include <unistd.h>
#else
#include <Windows.h>
#include <fcntl.h>
#include <io.h>
#include "getopt/getopt.h"
#endif
#include <semaphore.h>
#include <pthread.h>
#include <libusb.h>
#include "rtl-sdr.h"
#ifdef _WIN32
#define sleep Sleep
#undef min
#undef max
#endif
#define ADSB_RATE 2000000
#define ADSB_FREQ 1090000000
#define DEFAULT_ASYNC_BUF_NUMBER 32
#define DEFAULT_BUF_LENGTH (128 * 16384)
#define AUTO_GAIN -100
static pthread_t demod_thread;
static sem_t data_ready;
static volatile int do_exit = 0;
static rtlsdr_dev_t *dev = NULL;
/* todo, bundle these up in a struct */
uint8_t *buffer;
int raw_output = 0;
int short_output = 0;
int allowed_errors = 5;
FILE *file;
int adsb_frame[14];
#define preamble_len 16
#define long_frame 112
#define short_frame 56
void usage(void)
{
fprintf(stderr,
"rtl_adsb, a simple ADS-B decoder\n\n"
"Use:\trtl_adsb [-R] [-g gain] [-p ppm] [output file]\n"
"\t[-d device_index (default: 0)]\n"
"\t[-R output raw bitstream (default: off)]\n"
"\t[-S show short frames (default: off)]\n"
"\t[-e allowed_errors (default: 5)]\n"
"\t[-g tuner_gain (default: automatic)]\n"
"\t[-p ppm_error (default: 0)]\n"
"\tfilename (a '-' dumps samples to stdout)\n"
"\t (omitting the filename also uses stdout)\n\n"
"Streaming with netcat:\n"
"\trtl_adsb -R | netcat -lp 8080\n"
"\twhile true; do rtl_adsb -R | nc -lp 8080; done\n"
"\n");
exit(1);
}
#ifdef _WIN32
BOOL WINAPI
sighandler(int signum)
{
if (CTRL_C_EVENT == signum) {
fprintf(stderr, "Signal caught, exiting!\n");
do_exit = 1;
rtlsdr_cancel_async(dev);
return TRUE;
}
return FALSE;
}
#else
static void sighandler(int signum)
{
fprintf(stderr, "Signal caught, exiting!\n");
do_exit = 1;
rtlsdr_cancel_async(dev);
}
#endif
void display(int *frame, int len)
{
int i;
if (!short_output && len <= short_frame) {
return;}
if (raw_output) {
fprintf(file, "*");
for (i=0; i<((len+7)/8); i++) {
fprintf(file, "%02x", frame[i]);}
fprintf(file, ";\r\n");
return;
}
fprintf(file, "----------\n");
fprintf(file, "DF=%x CA=%x\n", (frame[0] >> 3) & 0x1f, frame[0] & 0x07);
fprintf(file, "ICAO Address=%06x\n", frame[1] << 16 | frame[2] << 8 | frame[3]);
if (len <= short_frame) {
return;}
fprintf(file, "PI=0x%06x\n", frame[11] << 16 | frame[12] << 8 | frame[13]);
fprintf(file, "Type Code=%x S.Type/Ant.=%x\n", (frame[4] >> 3) & 0x1f, frame[4] & 0x07);
}
int magnitute(unsigned char *buf, int len)
/* takes i/q, changes buf in place, returns new len */
{
int i, mag;
for (i=0; i<len; i+=2) {
mag = abs((int)buf[i]-128) + abs((int)buf[i+1]-128);
if (mag > 255) { // todo, compression
mag = 255;}
buf[i/2] = (unsigned char)mag;
}
return len/2;
}
inline unsigned char single_manchester(unsigned char a, unsigned char b, unsigned char c, unsigned char d)
/* takes 4 consecutive real samples, return 0 or 1, 255 on error */
{
int bit, bit_p;
bit_p = a > b;
bit = c > d;
if ( bit && bit_p && c > b && d < a) {
return 1;}
if ( bit && !bit_p && c > a && d < b) {
return 1;}
if (!bit && bit_p && c < a && d > b) {
return 0;}
if (!bit && !bit_p && c < b && d > a) {
return 0;}
return 255;
}
inline unsigned char min(unsigned char a, unsigned char b)
{
return a<b ? a : b;
}
inline unsigned char max(unsigned char a, unsigned char b)
{
return a>b ? a : b;
}
inline int preamble(unsigned char *buf, int len, int i)
/* returns 0/1 for preamble at index i */
{
int i2;
unsigned char low = 0;
unsigned char high = 255;
for (i2=0; i2<preamble_len; i2++) {
switch (i2) {
case 0:
case 2:
case 7:
case 9:
high = min(high, buf[i+i2]);
break;
default:
low = max(low, buf[i+i2]);
break;
}
if (high <= low) {
return 0;}
}
return 1;
}
void manchester(unsigned char *buf, int len)
/* overwrites magnitude buffer with valid bits (255 on errors) */
{
/* a and b hold old values to verify local manchester */
unsigned char a=0, b=0;
unsigned char bit;
int i, i2, start, errors;
// todo, allow wrap across buffers
i = 0;
while (i < len) {
/* find preamble */
for ( ; i < (len - preamble_len); i++) {
if (!preamble(buf, len, i)) {
continue;}
a = buf[i];
b = buf[i+1];
for (i2=0; i2<preamble_len; i2++) {
buf[i+i2] = 253;}
i += preamble_len;
//printf("preamble found\n");
break;
}
i2 = start = i;
errors = 0;
/* mark bits until encoding breaks */
for ( ; i < len; i+=2, i2++) {
bit = single_manchester(a, b, buf[i], buf[i+1]);
a = buf[i];
b = buf[i+1];
if (bit == 255) {
errors += 1;
if (errors > allowed_errors) {
buf[i2] = 255;
break;
} else {
bit = 0;
a = 0;
b = 255;
}
}
buf[i] = buf[i+1] = 254; /* to be overwritten */
buf[i2] = bit;
}
// todo, nuke short segments
//printf("%i\n", i2 - start);
}
}
void messages(unsigned char *buf, int len)
{
int i, i2, start, preamble_found;
int data_i, index, shift, frame_len;
// todo, allow wrap across buffers
for (i=0; i<len; i++) {
if (buf[i] > 1) {
continue;}
frame_len = long_frame;
data_i = 0;
for (index=0; index<14; index++) {
adsb_frame[index] = 0;}
for(; i<len && buf[i]<=1 && data_i<frame_len; i++, data_i++) {
if (buf[i]) {
index = data_i / 8;
shift = 7 - (data_i % 8);
adsb_frame[index] |= (unsigned char)(1<<shift);
}
if (data_i == 7) {
//if (adsb_frame[0] == 0) {
// break;}
if (adsb_frame[0] & 0x80) {
frame_len = long_frame;}
else {
frame_len = short_frame;}
}
}
// todo, check CRC
if (data_i < (frame_len-1)) {
continue;}
//fprintf(file, "bits: %i\n", data_i);
display(adsb_frame, frame_len);
fflush(file);
}
}
static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
{
int dr_val;
if (do_exit) {
return;}
memcpy(buffer, buf, len);
sem_getvalue(&data_ready, &dr_val);
if (dr_val <= 0) {
sem_post(&data_ready);}
}
static void *demod_thread_fn(void *arg)
{
int len;
while (!do_exit) {
sem_wait(&data_ready);
len = magnitute(buffer, DEFAULT_BUF_LENGTH);
manchester(buffer, len);
messages(buffer, len);
//fsync(file);
}
rtlsdr_cancel_async(dev);
return 0;
}
int main(int argc, char **argv)
{
#ifndef _WIN32
struct sigaction sigact;
#endif
char *filename = NULL;
int n_read, r, opt;
int i, gain = AUTO_GAIN; // tenths of a dB
uint32_t dev_index = 0;
int device_count;
int ppm_error = 0;
char vendor[256], product[256], serial[256];
sem_init(&data_ready, 0, 0);
while ((opt = getopt(argc, argv, "g:p:e:RS")) != -1)
{
switch (opt) {
case 'd':
dev_index = atoi(optarg);
break;
case 'g':
gain = (int)(atof(optarg) * 10);
break;
case 'p':
ppm_error = atoi(optarg);
break;
case 'R':
raw_output = 1;
break;
case 'S':
short_output = 1;
break;
case 'e':
allowed_errors = atoi(optarg);
break;
default:
usage();
return 0;
}
}
if (argc <= optind) {
//usage();
filename = "-";
} else {
filename = argv[optind];
}
buffer = malloc(DEFAULT_BUF_LENGTH * sizeof(uint8_t));
device_count = rtlsdr_get_device_count();
if (!device_count) {
fprintf(stderr, "No supported devices found.\n");
exit(1);
}
fprintf(stderr, "Found %d device(s):\n", device_count);
for (i = 0; i < device_count; i++) {
rtlsdr_get_device_usb_strings(i, vendor, product, serial);
fprintf(stderr, " %d: %s, %s, SN: %s\n", i, vendor, product, serial);
}
fprintf(stderr, "\n");
fprintf(stderr, "Using device %d: %s\n",
dev_index, rtlsdr_get_device_name(dev_index));
r = rtlsdr_open(&dev, dev_index);
if (r < 0) {
fprintf(stderr, "Failed to open rtlsdr device #%d.\n", dev_index);
exit(1);
}
#ifndef _WIN32
sigact.sa_handler = sighandler;
sigemptyset(&sigact.sa_mask);
sigact.sa_flags = 0;
sigaction(SIGINT, &sigact, NULL);
sigaction(SIGTERM, &sigact, NULL);
sigaction(SIGQUIT, &sigact, NULL);
sigaction(SIGPIPE, &sigact, NULL);
#else
SetConsoleCtrlHandler( (PHANDLER_ROUTINE) sighandler, TRUE );
#endif
if (strcmp(filename, "-") == 0) { /* Write samples to stdout */
file = stdout;
#ifdef _WIN32
_setmode(_fileno(file), _O_BINARY);
#endif
} else {
file = fopen(filename, "wb");
if (!file) {
fprintf(stderr, "Failed to open %s\n", filename);
exit(1);
}
}
/* Set the tuner gain */
if (gain == AUTO_GAIN) {
r = rtlsdr_set_tuner_gain_mode(dev, 0);
} else {
r = rtlsdr_set_tuner_gain_mode(dev, 1);
r = rtlsdr_set_tuner_gain(dev, gain);
}
if (r != 0) {
fprintf(stderr, "WARNING: Failed to set tuner gain.\n");
} else if (gain == AUTO_GAIN) {
fprintf(stderr, "Tuner gain set to automatic.\n");
} else {
fprintf(stderr, "Tuner gain set to %0.2f dB.\n", gain/10.0);
}
r = rtlsdr_set_freq_correction(dev, ppm_error);
r = rtlsdr_set_agc_mode(dev, 1);
/* Set the tuner frequency */
r = rtlsdr_set_center_freq(dev, ADSB_FREQ);
if (r < 0) {
fprintf(stderr, "WARNING: Failed to set center freq.\n");}
else {
fprintf(stderr, "Tuned to %u Hz.\n", ADSB_FREQ);}
/* Set the sample rate */
fprintf(stderr, "Sampling at %u Hz.\n", ADSB_RATE);
r = rtlsdr_set_sample_rate(dev, ADSB_RATE);
if (r < 0) {
fprintf(stderr, "WARNING: Failed to set sample rate.\n");}
/* Reset endpoint before we start reading from it (mandatory) */
r = rtlsdr_reset_buffer(dev);
if (r < 0) {
fprintf(stderr, "WARNING: Failed to reset buffers.\n");}
/* flush old junk */
sleep(1);
rtlsdr_read_sync(dev, NULL, 4096, NULL);
pthread_create(&demod_thread, NULL, demod_thread_fn, (void *)(NULL));
rtlsdr_read_async(dev, rtlsdr_callback, (void *)(NULL),
DEFAULT_ASYNC_BUF_NUMBER,
DEFAULT_BUF_LENGTH);
if (do_exit) {
fprintf(stderr, "\nUser cancel, exiting...\n");}
else {
fprintf(stderr, "\nLibrary error %d, exiting...\n", r);}
rtlsdr_cancel_async(dev);
if (file != stdout) {
fclose(file);}
rtlsdr_close(dev);
free(buffer);
return r >= 0 ? r : -r;
}
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