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dump1090/dump1090.h
Oliver Jowett 661246d347 Prefer to use global CPR decoding where possible. 
There is a danger in always using relative decoding where possible.
If there is an undetected error in the first pair of messages received,
then global CPR decoding will give a bad position, and subsequent
relative decoding will just walk around near that bad position even
though many error-free pairs of odd/even messages may have been received.

The first pair of position messages also tends to be the most error-prone, as
they are usually received at the extreme edge of receiver range.

(I see this happen at least once a day in practice)

So, instead, prefer to use global decoding when we have sufficiently recent data.
With recent data this should always be as good as relative decoding, and it
avoids getting stuck with bad data for long periods of time. If we don't have
enough recent data for a global solution, fall back to relative decoding.
2014-09-25 17:10:55 +01:00

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// dump1090, a Mode S messages decoder for RTLSDR devices.
//
// Copyright (C) 2012 by Salvatore Sanfilippo <antirez@gmail.com>
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
#ifndef __DUMP1090_H
#define __DUMP1090_H
// File Version number
// ====================
// Format is : MajorVer.MinorVer.DayMonth.Year"
// MajorVer changes only with significant changes
// MinorVer changes when additional features are added, but not for bug fixes (range 00-99)
// DayDate & Year changes for all changes, including for bug fixes. It represent the release date of the update
//
#define MODES_DUMP1090_VERSION "1.09.0608.14"
// ============================= Include files ==========================
#ifndef _WIN32
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <pthread.h>
#include <stdint.h>
#include <errno.h>
#include <unistd.h>
#include <math.h>
#include <sys/time.h>
#include <sys/timeb.h>
#include <signal.h>
#include <fcntl.h>
#include <ctype.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include "rtl-sdr.h"
#include "anet.h"
#else
#include "winstubs.h" //Put everything Windows specific in here
#include "rtl-sdr.h"
#include "anet.h"
#endif
// ============================= #defines ===============================
//
// If you have a valid coaa.h, these values will come from it. If not,
// then you can enter your own values in the #else section here
//
#ifdef USER_LATITUDE
#define MODES_USER_LATITUDE_DFLT (USER_LATITUDE)
#define MODES_USER_LONGITUDE_DFLT (USER_LONGITUDE)
#else
#define MODES_USER_LATITUDE_DFLT (0.0)
#define MODES_USER_LONGITUDE_DFLT (0.0)
#endif
#define MODES_DEFAULT_PPM 52
#define MODES_DEFAULT_RATE 2000000
#define MODES_DEFAULT_FREQ 1090000000
#define MODES_DEFAULT_WIDTH 1000
#define MODES_DEFAULT_HEIGHT 700
#define MODES_ASYNC_BUF_NUMBER 16
#define MODES_ASYNC_BUF_SIZE (16*16384) // 256k
#define MODES_ASYNC_BUF_SAMPLES (MODES_ASYNC_BUF_SIZE / 2) // Each sample is 2 bytes
#define MODES_AUTO_GAIN -100 // Use automatic gain
#define MODES_MAX_GAIN 999999 // Use max available gain
#define MODES_MSG_SQUELCH_LEVEL 0x02FF // Average signal strength limit
#define MODES_MSG_ENCODER_ERRS 3 // Maximum number of encoding errors
// When changing, change also fixBitErrors() and modesInitErrorTable() !!
#define MODES_MAX_BITERRORS 2 // Global max for fixable bit erros
#define MODEAC_MSG_SAMPLES (25 * 2) // include up to the SPI bit
#define MODEAC_MSG_BYTES 2
#define MODEAC_MSG_SQUELCH_LEVEL 0x07FF // Average signal strength limit
#define MODEAC_MSG_FLAG (1<<0)
#define MODEAC_MSG_MODES_HIT (1<<1)
#define MODEAC_MSG_MODEA_HIT (1<<2)
#define MODEAC_MSG_MODEC_HIT (1<<3)
#define MODEAC_MSG_MODEA_ONLY (1<<4)
#define MODEAC_MSG_MODEC_OLD (1<<5)
#define MODES_PREAMBLE_US 8 // microseconds = bits
#define MODES_PREAMBLE_SAMPLES (MODES_PREAMBLE_US * 2)
#define MODES_PREAMBLE_SIZE (MODES_PREAMBLE_SAMPLES * sizeof(uint16_t))
#define MODES_LONG_MSG_BYTES 14
#define MODES_SHORT_MSG_BYTES 7
#define MODES_LONG_MSG_BITS (MODES_LONG_MSG_BYTES * 8)
#define MODES_SHORT_MSG_BITS (MODES_SHORT_MSG_BYTES * 8)
#define MODES_LONG_MSG_SAMPLES (MODES_LONG_MSG_BITS * 2)
#define MODES_SHORT_MSG_SAMPLES (MODES_SHORT_MSG_BITS * 2)
#define MODES_LONG_MSG_SIZE (MODES_LONG_MSG_SAMPLES * sizeof(uint16_t))
#define MODES_SHORT_MSG_SIZE (MODES_SHORT_MSG_SAMPLES * sizeof(uint16_t))
#define MODES_RAWOUT_BUF_SIZE (1500)
#define MODES_RAWOUT_BUF_FLUSH (MODES_RAWOUT_BUF_SIZE - 200)
#define MODES_RAWOUT_BUF_RATE (1000) // 1000 * 64mS = 1 Min approx
#define MODES_ICAO_CACHE_LEN 1024 // Power of two required
#define MODES_ICAO_CACHE_TTL 60 // Time to live of cached addresses
#define MODES_UNIT_FEET 0
#define MODES_UNIT_METERS 1
#define MODES_USER_LATLON_VALID (1<<0)
#define MODES_ACFLAGS_LATLON_VALID (1<<0) // Aircraft Lat/Lon is decoded
#define MODES_ACFLAGS_ALTITUDE_VALID (1<<1) // Aircraft altitude is known
#define MODES_ACFLAGS_HEADING_VALID (1<<2) // Aircraft heading is known
#define MODES_ACFLAGS_SPEED_VALID (1<<3) // Aircraft speed is known
#define MODES_ACFLAGS_VERTRATE_VALID (1<<4) // Aircraft vertical rate is known
#define MODES_ACFLAGS_SQUAWK_VALID (1<<5) // Aircraft Mode A Squawk is known
#define MODES_ACFLAGS_CALLSIGN_VALID (1<<6) // Aircraft Callsign Identity
#define MODES_ACFLAGS_EWSPEED_VALID (1<<7) // Aircraft East West Speed is known
#define MODES_ACFLAGS_NSSPEED_VALID (1<<8) // Aircraft North South Speed is known
#define MODES_ACFLAGS_AOG (1<<9) // Aircraft is On the Ground
#define MODES_ACFLAGS_LLEVEN_VALID (1<<10) // Aircraft Even Lot/Lon is known
#define MODES_ACFLAGS_LLODD_VALID (1<<11) // Aircraft Odd Lot/Lon is known
#define MODES_ACFLAGS_AOG_VALID (1<<12) // MODES_ACFLAGS_AOG is valid
#define MODES_ACFLAGS_FS_VALID (1<<13) // Aircraft Flight Status is known
#define MODES_ACFLAGS_NSEWSPD_VALID (1<<14) // Aircraft EW and NS Speed is known
#define MODES_ACFLAGS_LATLON_REL_OK (1<<15) // Indicates it's OK to do a relative CPR
#define MODES_ACFLAGS_LLEITHER_VALID (MODES_ACFLAGS_LLEVEN_VALID | MODES_ACFLAGS_LLODD_VALID)
#define MODES_ACFLAGS_LLBOTH_VALID (MODES_ACFLAGS_LLEVEN_VALID | MODES_ACFLAGS_LLODD_VALID)
#define MODES_ACFLAGS_AOG_GROUND (MODES_ACFLAGS_AOG_VALID | MODES_ACFLAGS_AOG)
#define MODES_DEBUG_DEMOD (1<<0)
#define MODES_DEBUG_DEMODERR (1<<1)
#define MODES_DEBUG_BADCRC (1<<2)
#define MODES_DEBUG_GOODCRC (1<<3)
#define MODES_DEBUG_NOPREAMBLE (1<<4)
#define MODES_DEBUG_NET (1<<5)
#define MODES_DEBUG_JS (1<<6)
// When debug is set to MODES_DEBUG_NOPREAMBLE, the first sample must be
// at least greater than a given level for us to dump the signal.
#define MODES_DEBUG_NOPREAMBLE_LEVEL 25
#define MODES_INTERACTIVE_REFRESH_TIME 250 // Milliseconds
#define MODES_INTERACTIVE_ROWS 22 // Rows on screen
#define MODES_INTERACTIVE_DELETE_TTL 300 // Delete from the list after 300 seconds
#define MODES_INTERACTIVE_DISPLAY_TTL 60 // Delete from display after 60 seconds
#define MODES_NET_HEARTBEAT_RATE 900 // Each block is approx 65mS - default is > 1 min
#define MODES_NET_SERVICES_NUM 6
#define MODES_NET_INPUT_RAW_PORT 30001
#define MODES_NET_OUTPUT_RAW_PORT 30002
#define MODES_NET_OUTPUT_SBS_PORT 30003
#define MODES_NET_INPUT_BEAST_PORT 30004
#define MODES_NET_OUTPUT_BEAST_PORT 30005
#define MODES_NET_HTTP_PORT 8080
#define MODES_CLIENT_BUF_SIZE 1024
#define MODES_NET_SNDBUF_SIZE (1024*64)
#define MODES_NET_SNDBUF_MAX (7)
#ifndef HTMLPATH
#define HTMLPATH "./public_html" // default path for gmap.html etc
#endif
#define MODES_NOTUSED(V) ((void) V)
//======================== structure declarations =========================
// Structure used to describe a networking client
struct client {
struct client* next; // Pointer to next client
int fd; // File descriptor
int service; // TCP port the client is connected to
int buflen; // Amount of data on buffer
char buf[MODES_CLIENT_BUF_SIZE+1]; // Read buffer
};
// Structure used to describe an aircraft in iteractive mode
struct aircraft {
uint32_t addr; // ICAO address
char flight[16]; // Flight number
unsigned char signalLevel[8]; // Last 8 Signal Amplitudes
int altitude; // Altitude
int speed; // Velocity
int track; // Angle of flight
int vert_rate; // Vertical rate.
time_t seen; // Time at which the last packet was received
time_t seenLatLon; // Time at which the last lat long was calculated
uint64_t timestamp; // Timestamp at which the last packet was received
uint64_t timestampLatLon;// Timestamp at which the last lat long was calculated
long messages; // Number of Mode S messages received
int modeA; // Squawk
int modeC; // Altitude
long modeAcount; // Mode A Squawk hit Count
long modeCcount; // Mode C Altitude hit Count
int modeACflags; // Flags for mode A/C recognition
// Encoded latitude and longitude as extracted by odd and even CPR encoded messages
int odd_cprlat;
int odd_cprlon;
int even_cprlat;
int even_cprlon;
uint64_t odd_cprtime;
uint64_t even_cprtime;
double lat, lon; // Coordinated obtained from CPR encoded data
int bFlags; // Flags related to valid fields in this structure
struct aircraft *next; // Next aircraft in our linked list
};
struct stDF {
struct stDF *pNext; // Pointer to next item in the linked list
struct stDF *pPrev; // Pointer to previous item in the linked list
struct aircraft *pAircraft; // Pointer to the Aircraft structure for this DF
time_t seen; // Dos/UNIX Time at which the this packet was received
uint64_t llTimestamp; // Timestamp at which the this packet was received
uint32_t addr; // Timestamp at which the this packet was received
unsigned char msg[MODES_LONG_MSG_BYTES]; // the binary
} tDF;
// Program global state
struct { // Internal state
pthread_t reader_thread;
pthread_mutex_t data_mutex; // Mutex to synchronize buffer access
pthread_cond_t data_cond; // Conditional variable associated
uint16_t *pData [MODES_ASYNC_BUF_NUMBER]; // Raw IQ sample buffers from RTL
struct timeb stSystemTimeRTL[MODES_ASYNC_BUF_NUMBER]; // System time when RTL passed us this block
int iDataIn; // Fifo input pointer
int iDataOut; // Fifo output pointer
int iDataReady; // Fifo content count
int iDataLost; // Count of missed buffers
uint16_t *pFileData; // Raw IQ samples buffer (from a File)
uint16_t *magnitude; // Magnitude vector
uint64_t timestampBlk; // Timestamp of the start of the current block
struct timeb stSystemTimeBlk; // System time when RTL passed us currently processing this block
int fd; // --ifile option file descriptor
uint32_t *icao_cache; // Recently seen ICAO addresses cache
uint16_t *maglut; // I/Q -> Magnitude lookup table
int exit; // Exit from the main loop when true
// RTLSDR
int dev_index;
int gain;
int enable_agc;
rtlsdr_dev_t *dev;
int freq;
int ppm_error;
// Networking
char aneterr[ANET_ERR_LEN];
struct client *clients; // Our clients
int sbsos; // SBS output listening socket
int ros; // Raw output listening socket
int ris; // Raw input listening socket
int bos; // Beast output listening socket
int bis; // Beast input listening socket
int https; // HTTP listening socket
char *rawOut; // Buffer for building raw output data
int rawOutUsed; // How much of the buffer is currently used
char *beastOut; // Buffer for building beast output data
int beastOutUsed; // How much if the buffer is currently used
#ifdef _WIN32
WSADATA wsaData; // Windows socket initialisation
#endif
// Configuration
char *filename; // Input form file, --ifile option
int phase_enhance; // Enable phase enhancement if true
int nfix_crc; // Number of crc bit error(s) to correct
int check_crc; // Only display messages with good CRC
int raw; // Raw output format
int beast; // Beast binary format output
int mode_ac; // Enable decoding of SSR Modes A & C
int debug; // Debugging mode
int net; // Enable networking
int net_only; // Enable just networking
int net_heartbeat_count; // TCP heartbeat counter
int net_heartbeat_rate; // TCP heartbeat rate
int net_output_sbs_port; // SBS output TCP port
int net_output_raw_size; // Minimum Size of the output raw data
int net_output_raw_rate; // Rate (in 64mS increments) of output raw data
int net_output_raw_rate_count; // Rate (in 64mS increments) of output raw data
int net_output_raw_port; // Raw output TCP port
int net_input_raw_port; // Raw input TCP port
int net_output_beast_port; // Beast output TCP port
int net_input_beast_port; // Beast input TCP port
int net_http_port; // HTTP port
int net_sndbuf_size; // TCP output buffer size (64Kb * 2^n)
int quiet; // Suppress stdout
int interactive; // Interactive mode
int interactive_rows; // Interactive mode: max number of rows
int interactive_display_ttl; // Interactive mode: TTL display
int interactive_delete_ttl; // Interactive mode: TTL before deletion
int stats; // Print stats at exit in --ifile mode
int onlyaddr; // Print only ICAO addresses
int metric; // Use metric units
int mlat; // Use Beast ascii format for raw data output, i.e. @...; iso *...;
int interactive_rtl1090; // flight table in interactive mode is formatted like RTL1090
// User details
double fUserLat; // Users receiver/antenna lat/lon needed for initial surface location
double fUserLon; // Users receiver/antenna lat/lon needed for initial surface location
int bUserFlags; // Flags relating to the user details
// Interactive mode
struct aircraft *aircrafts;
uint64_t interactive_last_update; // Last screen update in milliseconds
time_t last_cleanup_time; // Last cleanup time in seconds
// DF List mode
int bEnableDFLogging; // Set to enable DF Logging
pthread_mutex_t pDF_mutex; // Mutex to synchronize pDF access
struct stDF *pDF; // Pointer to DF list
// Statistics
unsigned int stat_valid_preamble;
unsigned int stat_demodulated0;
unsigned int stat_demodulated1;
unsigned int stat_demodulated2;
unsigned int stat_demodulated3;
unsigned int stat_goodcrc;
unsigned int stat_badcrc;
unsigned int stat_fixed;
// Histogram of fixed bit errors: index 0 for single bit erros,
// index 1 for double bit errors etc.
unsigned int stat_bit_fix[MODES_MAX_BITERRORS];
unsigned int stat_http_requests;
unsigned int stat_sbs_connections;
unsigned int stat_raw_connections;
unsigned int stat_beast_connections;
unsigned int stat_out_of_phase;
unsigned int stat_ph_demodulated0;
unsigned int stat_ph_demodulated1;
unsigned int stat_ph_demodulated2;
unsigned int stat_ph_demodulated3;
unsigned int stat_ph_goodcrc;
unsigned int stat_ph_badcrc;
unsigned int stat_ph_fixed;
// Histogram of fixed bit errors: index 0 for single bit erros,
// index 1 for double bit errors etc.
unsigned int stat_ph_bit_fix[MODES_MAX_BITERRORS];
unsigned int stat_DF_Len_Corrected;
unsigned int stat_DF_Type_Corrected;
unsigned int stat_ModeAC;
} Modes;
// The struct we use to store information about a decoded message.
struct modesMessage {
// Generic fields
unsigned char msg[MODES_LONG_MSG_BYTES]; // Binary message.
int msgbits; // Number of bits in message
int msgtype; // Downlink format #
int crcok; // True if CRC was valid
uint32_t crc; // Message CRC
int correctedbits; // No. of bits corrected
char corrected[MODES_MAX_BITERRORS]; // corrected bit positions
uint32_t addr; // ICAO Address from bytes 1 2 and 3
int phase_corrected; // True if phase correction was applied
uint64_t timestampMsg; // Timestamp of the message
int remote; // If set this message is from a remote station
unsigned char signalLevel; // Signal Amplitude
// DF 11
int ca; // Responder capabilities
int iid;
// DF 17, DF 18
int metype; // Extended squitter message type.
int mesub; // Extended squitter message subtype.
int heading; // Reported by aircraft, or computed from from EW and NS velocity
int raw_latitude; // Non decoded latitude.
int raw_longitude; // Non decoded longitude.
double fLat; // Coordinates obtained from CPR encoded data if/when decoded
double fLon; // Coordinates obtained from CPR encoded data if/when decoded
char flight[16]; // 8 chars flight number.
int ew_velocity; // E/W velocity.
int ns_velocity; // N/S velocity.
int vert_rate; // Vertical rate.
int velocity; // Reported by aircraft, or computed from from EW and NS velocity
// DF4, DF5, DF20, DF21
int fs; // Flight status for DF4,5,20,21
int modeA; // 13 bits identity (Squawk).
// Fields used by multiple message types.
int altitude;
int unit;
int bFlags; // Flags related to fields in this structure
};
// ======================== function declarations =========================
#ifdef __cplusplus
extern "C" {
#endif
//
// Functions exported from mode_ac.c
//
int detectModeA (uint16_t *m, struct modesMessage *mm);
void decodeModeAMessage(struct modesMessage *mm, int ModeA);
int ModeAToModeC (unsigned int ModeA);
//
// Functions exported from mode_s.c
//
void detectModeS (uint16_t *m, uint32_t mlen);
void decodeModesMessage (struct modesMessage *mm, unsigned char *msg);
void displayModesMessage(struct modesMessage *mm);
void useModesMessage (struct modesMessage *mm);
void computeMagnitudeVector(uint16_t *pData);
int decodeCPR (struct aircraft *a, int fflag, int surface);
int decodeCPRrelative (struct aircraft *a, int fflag, int surface);
void modesInitErrorInfo ();
//
// Functions exported from interactive.c
//
struct aircraft* interactiveReceiveData(struct modesMessage *mm);
void interactiveShowData(void);
void interactiveRemoveStaleAircrafts(void);
int decodeBinMessage (struct client *c, char *p);
struct aircraft *interactiveFindAircraft(uint32_t addr);
struct stDF *interactiveFindDF (uint32_t addr);
//
// Functions exported from net_io.c
//
void modesInitNet (void);
void modesReadFromClients (void);
void modesSendAllClients (int service, void *msg, int len);
void modesQueueOutput (struct modesMessage *mm);
void modesReadFromClient(struct client *c, char *sep, int(*handler)(struct client *, char *));
#ifdef __cplusplus
}
#endif
#endif // __DUMP1090_H
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