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This commit is contained in:
Oliver Jowett 2016-05-31 12:58:44 +01:00
parent 824954aeca 8b341f39e5
commit 43e380912d
11 changed files with 38 additions and 1045 deletions
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2
Makefile
View file

@ -47,7 +47,7 @@ all: dump1090 view1090
dump1090.o: CFLAGS += `pkg-config --cflags librtlsdr`
dump1090: dump1090.o anet.o interactive.o mode_ac.o mode_s.o net_io.o crc.o demod_2000.o demod_2400.o stats.o cpr.o icao_filter.o track.o util.o convert.o $(COMPAT)
dump1090: dump1090.o anet.o interactive.o mode_ac.o mode_s.o net_io.o crc.o demod_2400.o stats.o cpr.o icao_filter.o track.o util.o convert.o $(COMPAT)
$(CC) -g -o $@ $^ $(LIBS) $(LIBS_RTL) $(LDFLAGS)
view1090: view1090.o anet.o interactive.o mode_ac.o mode_s.o net_io.o crc.o stats.o cpr.o icao_filter.o track.o util.o $(COMPAT)

4
README.md
View file

@ -25,8 +25,8 @@ See the file COPYING for details.
There is a repository that contains the current releases. To set up the repository:
````
$ wget https://github.com/mutability/mutability-repo/releases/download/v0.1.0/mutability-repo_0.1.0_armhf.deb
$ sudo dpkg -i mutability-repo_0.1.0_armhf.deb
$ wget https://github.com/mutability/mutability-repo/releases/download/v0.1.1/mutability-repo_0.1.1_armhf.deb
$ sudo dpkg -i mutability-repo_0.1.1_armhf.deb
````
Then you can install and upgrade packages via apt-get as needed:

60
convert.c
View file

@ -26,42 +26,11 @@ struct converter_state {
float z1_Q;
};
static void convert_uc8_nodc_nopower(void *iq_data,
uint16_t *mag_data,
unsigned nsamples,
struct converter_state *state,
double *out_power)
{
uint16_t *in = iq_data;
unsigned i;
MODES_NOTUSED(state);
// unroll this a bit
for (i = 0; i < (nsamples>>3); ++i) {
*mag_data++ = Modes.maglut[*in++];
*mag_data++ = Modes.maglut[*in++];
*mag_data++ = Modes.maglut[*in++];
*mag_data++ = Modes.maglut[*in++];
*mag_data++ = Modes.maglut[*in++];
*mag_data++ = Modes.maglut[*in++];
*mag_data++ = Modes.maglut[*in++];
*mag_data++ = Modes.maglut[*in++];
}
for (i = 0; i < (nsamples&7); ++i) {
*mag_data++ = Modes.maglut[*in++];
}
if (out_power)
*out_power = 0.0; // not measured
}
static void convert_uc8_nodc_power(void *iq_data,
uint16_t *mag_data,
unsigned nsamples,
struct converter_state *state,
double *out_power)
static void convert_uc8_nodc(void *iq_data,
uint16_t *mag_data,
unsigned nsamples,
struct converter_state *state,
double *out_power)
{
uint16_t *in = iq_data;
unsigned i;
@ -251,23 +220,20 @@ static void convert_sc16q11_generic(void *iq_data,
static struct {
input_format_t format;
int can_filter_dc;
int can_compute_power;
iq_convert_fn fn;
const char *description;
} converters_table[] = {
// In order of preference
{ INPUT_UC8, 0, 0, convert_uc8_nodc_nopower, "UC8, integer/table path" },
{ INPUT_UC8, 0, 1, convert_uc8_nodc_power, "UC8, integer/table path, with power measurement" },
{ INPUT_UC8, 1, 1, convert_uc8_generic, "UC8, float path" },
{ INPUT_SC16, 1, 1, convert_sc16_generic, "SC16, float path" },
{ INPUT_SC16Q11, 1, 1, convert_sc16q11_generic, "SC16Q11, float path" },
{ 0, 0, 0, NULL, NULL }
{ INPUT_UC8, 0, convert_uc8_nodc, "UC8, integer/table path" },
{ INPUT_UC8, 1, convert_uc8_generic, "UC8, float path" },
{ INPUT_SC16, 1, convert_sc16_generic, "SC16, float path" },
{ INPUT_SC16Q11, 1, convert_sc16q11_generic, "SC16Q11, float path" },
{ 0, 0, NULL, NULL }
};
iq_convert_fn init_converter(input_format_t format,
double sample_rate,
int filter_dc,
int compute_power,
struct converter_state **out_state)
{
int i;
@ -277,14 +243,12 @@ iq_convert_fn init_converter(input_format_t format,
continue;
if (filter_dc && !converters_table[i].can_filter_dc)
continue;
if (compute_power && !converters_table[i].can_compute_power)
continue;
break;
}
if (!converters_table[i].fn) {
fprintf(stderr, "no suitable converter for format=%d power=%d dc=%d\n",
format, compute_power, filter_dc);
fprintf(stderr, "no suitable converter for format=%d dc=%d\n",
format, filter_dc);
return NULL;
}

1
convert.h
View file

@ -32,7 +32,6 @@ typedef void (*iq_convert_fn)(void *iq_data,
iq_convert_fn init_converter(input_format_t format,
double sample_rate,
int filter_dc,
int compute_power,
struct converter_state **out_state);
void cleanup_converter(struct converter_state *state);

2
debian/dump1090-fa.default vendored
View file

@ -4,7 +4,7 @@
# TODO: This needs to be generated from piaware-config.txt
#RECEIVER_OPTIONS="--device-index 0 --gain -10 --ppm 0 --oversample --phase-enhance --net-bo-port 30005 --fix"
#RECEIVER_OPTIONS="--device-index 0 --gain -10 --ppm 0 --net-bo-port 30005 --fix"
RECEIVER_OPTIONS="--net-only --net-bo-port 0"
DECODER_OPTIONS="--max-range 300"
NET_OPTIONS="--net --net-heartbeat 60 --net-ro-size 1000 --net-ro-interval 1 --net-http-port 0 --net-ri-port 0 --net-ro-port 30002 --net-sbs-port 30003 --net-bi-port 30104 --net-fatsv-port 0"

891
demod_2000.c
View file

@ -1,891 +0,0 @@
// Part of dump1090, a Mode S message decoder for RTLSDR devices.
//
// demod_2000.c: 2MHz Mode S demodulator.
//
// Copyright (c) 2014,2015 Oliver Jowett <oliver@mutability.co.uk>
//
// This file is free software: you may copy, redistribute 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 file 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/>.
// This file incorporates work covered by the following copyright and
// permission notice:
//
// 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.
#include "dump1090.h"
// Mode S 2.0MHz demodulator
//
// ===================== Mode A/C detection and decoding ===================
//
//
// This table is used to build the Mode A/C variable called ModeABits.Each
// bit period is inspected, and if it's value exceeds the threshold limit,
// then the value in this table is or-ed into ModeABits.
//
// At the end of message processing, ModeABits will be the decoded ModeA value.
//
// We can also flag noise in bits that should be zeros - the xx bits. Noise in
// these bits cause bits (31-16) in ModeABits to be set. Then at the end of message
// processing we can test for errors by looking at these bits.
//
uint32_t ModeABitTable[24] = {
0x00000000, // F1 = 1
0x00000010, // C1
0x00001000, // A1
0x00000020, // C2
0x00002000, // A2
0x00000040, // C4
0x00004000, // A4
0x40000000, // xx = 0 Set bit 30 if we see this high
0x00000100, // B1
0x00000001, // D1
0x00000200, // B2
0x00000002, // D2
0x00000400, // B4
0x00000004, // D4
0x00000000, // F2 = 1
0x08000000, // xx = 0 Set bit 27 if we see this high
0x04000000, // xx = 0 Set bit 26 if we see this high
0x00000080, // SPI
0x02000000, // xx = 0 Set bit 25 if we see this high
0x01000000, // xx = 0 Set bit 24 if we see this high
0x00800000, // xx = 0 Set bit 23 if we see this high
0x00400000, // xx = 0 Set bit 22 if we see this high
0x00200000, // xx = 0 Set bit 21 if we see this high
0x00100000, // xx = 0 Set bit 20 if we see this high
};
//
// This table is used to produce an error variable called ModeAErrs.Each
// inter-bit period is inspected, and if it's value falls outside of the
// expected range, then the value in this table is or-ed into ModeAErrs.
//
// At the end of message processing, ModeAErrs will indicate if we saw
// any inter-bit anomolies, and the bits that are set will show which
// bits had them.
//
uint32_t ModeAMidTable[24] = {
0x80000000, // F1 = 1 Set bit 31 if we see F1_C1 error
0x00000010, // C1 Set bit 4 if we see C1_A1 error
0x00001000, // A1 Set bit 12 if we see A1_C2 error
0x00000020, // C2 Set bit 5 if we see C2_A2 error
0x00002000, // A2 Set bit 13 if we see A2_C4 error
0x00000040, // C4 Set bit 6 if we see C3_A4 error
0x00004000, // A4 Set bit 14 if we see A4_xx error
0x40000000, // xx = 0 Set bit 30 if we see xx_B1 error
0x00000100, // B1 Set bit 8 if we see B1_D1 error
0x00000001, // D1 Set bit 0 if we see D1_B2 error
0x00000200, // B2 Set bit 9 if we see B2_D2 error
0x00000002, // D2 Set bit 1 if we see D2_B4 error
0x00000400, // B4 Set bit 10 if we see B4_D4 error
0x00000004, // D4 Set bit 2 if we see D4_F2 error
0x20000000, // F2 = 1 Set bit 29 if we see F2_xx error
0x08000000, // xx = 0 Set bit 27 if we see xx_xx error
0x04000000, // xx = 0 Set bit 26 if we see xx_SPI error
0x00000080, // SPI Set bit 15 if we see SPI_xx error
0x02000000, // xx = 0 Set bit 25 if we see xx_xx error
0x01000000, // xx = 0 Set bit 24 if we see xx_xx error
0x00800000, // xx = 0 Set bit 23 if we see xx_xx error
0x00400000, // xx = 0 Set bit 22 if we see xx_xx error
0x00200000, // xx = 0 Set bit 21 if we see xx_xx error
0x00100000, // xx = 0 Set bit 20 if we see xx_xx error
};
//
// The "off air" format is,,
// _F1_C1_A1_C2_A2_C4_A4_xx_B1_D1_B2_D2_B4_D4_F2_xx_xx_SPI_
//
// Bit spacing is 1.45uS, with 0.45uS high, and 1.00us low. This is a problem
// because we ase sampling at 2Mhz (500nS) so we are below Nyquist.
//
// The bit spacings are..
// F1 : 0.00,
// 1.45, 2.90, 4.35, 5.80, 7.25, 8.70,
// X : 10.15,
// : 11.60, 13.05, 14.50, 15.95, 17.40, 18.85,
// F2 : 20.30,
// X : 21.75, 23.20, 24.65
//
// This equates to the following sample point centers at 2Mhz.
// [ 0.0],
// [ 2.9], [ 5.8], [ 8.7], [11.6], [14.5], [17.4],
// [20.3],
// [23.2], [26.1], [29.0], [31.9], [34.8], [37.7]
// [40.6]
// [43.5], [46.4], [49.3]
//
// We know that this is a supposed to be a binary stream, so the signal
// should either be a 1 or a 0. Therefore, any energy above the noise level
// in two adjacent samples must be from the same pulse, so we can simply
// add the values together..
//
int detectModeA(uint16_t *m, struct modesMessage *mm)
{
int j, lastBitWasOne;
int ModeABits = 0;
int ModeAErrs = 0;
int byte, bit;
int thisSample, lastBit, lastSpace = 0;
int m0, m1, m2, m3, mPhase;
int n0, n1, n2 ,n3;
int F1_sig, F1_noise;
int F2_sig, F2_noise;
int fSig, fNoise, fLevel, fLoLo;
// m[0] contains the energy from 0 -> 499 nS
// m[1] contains the energy from 500 -> 999 nS
// m[2] contains the energy from 1000 -> 1499 nS
// m[3] contains the energy from 1500 -> 1999 nS
//
// We are looking for a Frame bit (F1) whose width is 450nS, followed by
// 1000nS of quiet.
//
// The width of the frame bit is 450nS, which is 90% of our sample rate.
// Therefore, in an ideal world, all the energy for the frame bit will be
// in a single sample, preceeded by (at least) one zero, and followed by
// two zeros, Best case we can look for ...
//
// 0 - 1 - 0 - 0
//
// However, our samples are not phase aligned, so some of the energy from
// each bit could be spread over two consecutive samples. Worst case is
// that we sample half in one bit, and half in the next. In that case,
// we're looking for
//
// 0 - 0.5 - 0.5 - 0.
m0 = m[0]; m1 = m[1];
if (m0 >= m1) // m1 *must* be bigger than m0 for this to be F1
{return (0);}
m2 = m[2]; m3 = m[3];
//
// if (m2 <= m0), then assume the sample bob on (Phase == 0), so don't look at m3
if ((m2 <= m0) || (m2 < m3))
{m3 = m2; m2 = m0;}
if ( (m3 >= m1) // m1 must be bigger than m3
|| (m0 > m2) // m2 can be equal to m0 if ( 0,1,0,0 )
|| (m3 > m2) ) // m2 can be equal to m3 if ( 0,1,0,0 )
{return (0);}
// m0 = noise
// m1 = noise + (signal * X))
// m2 = noise + (signal * (1-X))
// m3 = noise
//
// Hence, assuming all 4 samples have similar amounts of noise in them
// signal = (m1 + m2) - ((m0 + m3) * 2)
// noise = (m0 + m3) / 2
//
F1_sig = (m1 + m2) - ((m0 + m3) << 1);
F1_noise = (m0 + m3) >> 1;
if ( (F1_sig < MODEAC_MSG_SQUELCH_LEVEL) // minimum required F1 signal amplitude
|| (F1_sig < (F1_noise << 2)) ) // minimum allowable Sig/Noise ratio 4:1
{return (0);}
// If we get here then we have a potential F1, so look for an equally valid F2 20.3uS later
//
// Our F1 is centered somewhere between samples m[1] and m[2]. We can guestimate where F2 is
// by comparing the ratio of m1 and m2, and adding on 20.3 uS (40.6 samples)
//
mPhase = ((m2 * 20) / (m1 + m2));
byte = (mPhase + 812) / 20;
n0 = m[byte++]; n1 = m[byte++];
if (n0 >= n1) // n1 *must* be bigger than n0 for this to be F2
{return (0);}
n2 = m[byte++];
//
// if the sample bob on (Phase == 0), don't look at n3
//
if ((mPhase + 812) % 20)
{n3 = m[byte++];}
else
{n3 = n2; n2 = n0;}
if ( (n3 >= n1) // n1 must be bigger than n3
|| (n0 > n2) // n2 can be equal to n0 ( 0,1,0,0 )
|| (n3 > n2) ) // n2 can be equal to n3 ( 0,1,0,0 )
{return (0);}
F2_sig = (n1 + n2) - ((n0 + n3) << 1);
F2_noise = (n0 + n3) >> 1;
if ( (F2_sig < MODEAC_MSG_SQUELCH_LEVEL) // minimum required F2 signal amplitude
|| (F2_sig < (F2_noise << 2)) ) // maximum allowable Sig/Noise ratio 4:1
{return (0);}
fSig = (F1_sig + F2_sig) >> 1;
fNoise = (F1_noise + F2_noise) >> 1;
fLoLo = fNoise + (fSig >> 2); // 1/2
fLevel = fNoise + (fSig >> 1);
lastBitWasOne = 1;
lastBit = F1_sig;
//
// Now step by a half ModeA bit, 0.725nS, which is 1.45 samples, which is 29/20
// No need to do bit 0 because we've already selected it as a valid F1
// Do several bits past the SPI to increase error rejection
//
for (j = 1, mPhase += 29; j < 48; mPhase += 29, j ++)
{
byte = 1 + (mPhase / 20);
thisSample = m[byte] - fNoise;
if (mPhase % 20) // If the bit is split over two samples...
{thisSample += (m[byte+1] - fNoise);} // add in the second sample's energy
// If we're calculating a space value
if (j & 1)
{lastSpace = thisSample;}
else
{// We're calculating a new bit value
bit = j >> 1;
if (thisSample >= fLevel)
{// We're calculating a new bit value, and its a one
ModeABits |= ModeABitTable[bit--]; // or in the correct bit
if (lastBitWasOne)
{ // This bit is one, last bit was one, so check the last space is somewhere less than one
if ( (lastSpace >= (thisSample>>1)) || (lastSpace >= lastBit) )
{ModeAErrs |= ModeAMidTable[bit];}
}
else
{// This bit,is one, last bit was zero, so check the last space is somewhere less than one
if (lastSpace >= (thisSample >> 1))
{ModeAErrs |= ModeAMidTable[bit];}
}
lastBitWasOne = 1;
}
else
{// We're calculating a new bit value, and its a zero
if (lastBitWasOne)
{ // This bit is zero, last bit was one, so check the last space is somewhere in between
if (lastSpace >= lastBit)
{ModeAErrs |= ModeAMidTable[bit];}
}
else
{// This bit,is zero, last bit was zero, so check the last space is zero too
if (lastSpace >= fLoLo)
{ModeAErrs |= ModeAMidTable[bit];}
}
lastBitWasOne = 0;
}
lastBit = (thisSample >> 1);
}
}
//
// Output format is : 00:A4:A2:A1:00:B4:B2:B1:00:C4:C2:C1:00:D4:D2:D1
//
if ((ModeABits < 3) || (ModeABits & 0xFFFF8808) || (ModeAErrs) )
{return (ModeABits = 0);}
mm->signalLevel = (fSig + fNoise) * (fSig + fNoise) / MAX_POWER;
return ModeABits;
}
// ============================== Debugging =================================
//
// Helper function for dumpMagnitudeVector().
// It prints a single bar used to display raw signals.
//
// Since every magnitude sample is between 0-255, the function uses
// up to 63 characters for every bar. Every character represents
// a length of 4, 3, 2, 1, specifically:
//
// "O" is 4
// "o" is 3
// "-" is 2
// "." is 1
//
static void dumpMagnitudeBar(int index, int magnitude) {
char *set = " .-o";
char buf[256];
int div = magnitude / 256 / 4;
int rem = magnitude / 256 % 4;
memset(buf,'O',div);
buf[div] = set[rem];
buf[div+1] = '\0';
if (index >= 0)
printf("[%.3d] |%-66s 0x%04X\n", index, buf, magnitude);
else
printf("[%.2d] |%-66s 0x%04X\n", index, buf, magnitude);
}
//
//=========================================================================
//
// Display an ASCII-art alike graphical representation of the undecoded
// message as a magnitude signal.
//
// The message starts at the specified offset in the "m" buffer.
// The function will display enough data to cover a short 56 bit message.
//
// If possible a few samples before the start of the messsage are included
// for context.
//
static void dumpMagnitudeVector(uint16_t *m, uint32_t offset) {
uint32_t padding = 5; // Show a few samples before the actual start.
uint32_t start = (offset < padding) ? 0 : offset-padding;
uint32_t end = offset + (MODES_PREAMBLE_SAMPLES)+(MODES_SHORT_MSG_SAMPLES) - 1;
uint32_t j;
for (j = start; j <= end; j++) {
dumpMagnitudeBar(j-offset, m[j]);
}
}
//
//=========================================================================
//
// Produce a raw representation of the message as a Javascript file
// loadable by debug.html.
//
static void dumpRawMessageJS(char *descr, unsigned char *msg,
uint16_t *m, uint32_t offset, struct errorinfo *ei)
{
int padding = 5; // Show a few samples before the actual start.
int start = offset - padding;
int end = offset + (MODES_PREAMBLE_SAMPLES)+(MODES_LONG_MSG_SAMPLES) - 1;
FILE *fp;
int j;
if ((fp = fopen("frames.js","a")) == NULL) {
fprintf(stderr, "Error opening frames.js: %s\n", strerror(errno));
exit(1);
}
fprintf(fp,"frames.push({\"descr\": \"%s\", \"mag\": [", descr);
for (j = start; j <= end; j++) {
fprintf(fp,"%d", j < 0 ? 0 : m[j]);
if (j != end) fprintf(fp,",");
}
fprintf(fp, "], ");
for (j = 0; j < MODES_MAX_BITERRORS; ++j)
fprintf(fp,"\"fix%d\": %d, ", j, ei->bit[j]);
fprintf(fp, "\"bits\": %d, \"hex\": \"", modesMessageLenByType(msg[0]>>3));
for (j = 0; j < MODES_LONG_MSG_BYTES; j++)
fprintf(fp,"\\x%02x",msg[j]);
fprintf(fp,"\"});\n");
fclose(fp);
}
//
//=========================================================================
//
// This is a wrapper for dumpMagnitudeVector() that also show the message
// in hex format with an additional description.
//
// descr is the additional message to show to describe the dump.
// msg points to the decoded message
// m is the original magnitude vector
// offset is the offset where the message starts
//
// The function also produces the Javascript file used by debug.html to
// display packets in a graphical format if the Javascript output was
// enabled.
//
static void dumpRawMessage(char *descr, unsigned char *msg, uint16_t *m, uint32_t offset) {
int j;
int msgtype = msg[0] >> 3;
struct errorinfo *ei = NULL;
if (msgtype == 17) {
int len = modesMessageLenByType(msgtype);
uint32_t csum = modesChecksum(msg, len);
ei = modesChecksumDiagnose(csum, len);
}
if (Modes.debug & MODES_DEBUG_JS) {
dumpRawMessageJS(descr, msg, m, offset, ei);
return;
}
printf("\n--- %s\n ", descr);
for (j = 0; j < MODES_LONG_MSG_BYTES; j++) {
printf("%02x",msg[j]);
if (j == MODES_SHORT_MSG_BYTES-1) printf(" ... ");
}
printf(" (DF %d, Fixable: %d)\n", msgtype, ei ? ei->errors : 0);
dumpMagnitudeVector(m,offset);
printf("---\n\n");
}
//
//=========================================================================
//
// Return -1 if the message is out of fase left-side
// Return 1 if the message is out of fase right-size
// Return 0 if the message is not particularly out of phase.
//
// Note: this function will access pPreamble[-1], so the caller should make sure to
// call it only if we are not at the start of the current buffer
//
static int detectOutOfPhase(uint16_t *pPreamble) {
if (pPreamble[ 3] > pPreamble[2]/3) return 1;
if (pPreamble[10] > pPreamble[9]/3) return 1;
if (pPreamble[ 6] > pPreamble[7]/3) return -1;
if (pPreamble[-1] > pPreamble[1]/3) return -1;
return 0;
}
static uint16_t clamped_scale(uint16_t v, uint16_t scale) {
uint32_t scaled = (uint32_t)v * scale / 16384;
if (scaled > 65535) return 65535;
return (uint16_t) scaled;
}
// This function decides whether we are sampling early or late,
// and by approximately how much, by looking at the energy in
// preamble bits before and after the expected pulse locations.
//
// It then deals with one sample pair at a time, comparing samples
// to make a decision about the bit value. Based on this decision it
// modifies the sample value of the *adjacent* sample which will
// contain some of the energy from the bit we just inspected.
//
// pPayload[0] should be the start of the preamble,
// pPayload[-1 .. MODES_PREAMBLE_SAMPLES + MODES_LONG_MSG_SAMPLES - 1] should be accessible.
// pPayload[MODES_PREAMBLE_SAMPLES .. MODES_PREAMBLE_SAMPLES + MODES_LONG_MSG_SAMPLES - 1] will be updated.
static void applyPhaseCorrection(uint16_t *pPayload) {
int j;
// we expect 1 bits at 0, 2, 7, 9
// and 0 bits at -1, 1, 3, 4, 5, 6, 8, 10, 11, 12, 13, 14
// use bits -1,6 for early detection (bit 0/7 arrived a little early, our sample period starts after the bit phase so we include some of the next bit)
// use bits 3,10 for late detection (bit 2/9 arrived a little late, our sample period starts before the bit phase so we include some of the last bit)
uint32_t onTime = (pPayload[0] + pPayload[2] + pPayload[7] + pPayload[9]);
uint32_t early = (pPayload[-1] + pPayload[6]) << 1;
uint32_t late = (pPayload[3] + pPayload[10]) << 1;
if (onTime == 0 && early == 0 && late == 0) {
// Blah, can't do anything with this, avoid a divide-by-zero
return;
}
if (early > late) {
// Our sample period starts late and so includes some of the next bit.
uint16_t scaleUp = 16384 + 16384 * early / (early + onTime); // 1 + early / (early+onTime)
uint16_t scaleDown = 16384 - 16384 * early / (early + onTime); // 1 - early / (early+onTime)
// trailing bits are 0; final data sample will be a bit low.
pPayload[MODES_PREAMBLE_SAMPLES + MODES_LONG_MSG_SAMPLES - 1] =
clamped_scale(pPayload[MODES_PREAMBLE_SAMPLES + MODES_LONG_MSG_SAMPLES - 1], scaleUp);
for (j = MODES_PREAMBLE_SAMPLES + MODES_LONG_MSG_SAMPLES - 2; j > MODES_PREAMBLE_SAMPLES; j -= 2) {
if (pPayload[j] > pPayload[j+1]) {
// x [1 0] y
// x overlapped with the "1" bit and is slightly high
pPayload[j-1] = clamped_scale(pPayload[j-1], scaleDown);
} else {
// x [0 1] y
// x overlapped with the "0" bit and is slightly low
pPayload[j-1] = clamped_scale(pPayload[j-1], scaleUp);
}
}
} else {
// Our sample period starts early and so includes some of the previous bit.
uint16_t scaleUp = 16384 + 16384 * late / (late + onTime); // 1 + late / (late+onTime)
uint16_t scaleDown = 16384 - 16384 * late / (late + onTime); // 1 - late / (late+onTime)
// leading bits are 0; first data sample will be a bit low.
pPayload[MODES_PREAMBLE_SAMPLES] = clamped_scale(pPayload[MODES_PREAMBLE_SAMPLES], scaleUp);
for (j = MODES_PREAMBLE_SAMPLES; j < MODES_PREAMBLE_SAMPLES + MODES_LONG_MSG_SAMPLES - 2; j += 2) {
if (pPayload[j] > pPayload[j+1]) {
// x [1 0] y
// y overlapped with the "0" bit and is slightly low
pPayload[j+2] = clamped_scale(pPayload[j+2], scaleUp);
} else {
// x [0 1] y
// y overlapped with the "1" bit and is slightly high
pPayload[j+2] = clamped_scale(pPayload[j+2], scaleDown);
}
}
}
}
//
//=========================================================================
//
// Detect a Mode S messages inside the magnitude buffer pointed by 'm' and of
// size 'mlen' bytes. Every detected Mode S message is convert it into a
// stream of bits and passed to the function to display it.
//
void demodulate2000(struct mag_buf *mag) {
struct modesMessage mm;
unsigned char msg[MODES_LONG_MSG_BYTES], *pMsg;
uint16_t aux[MODES_PREAMBLE_SAMPLES+MODES_LONG_MSG_SAMPLES+1];
uint32_t j;
int use_correction = 0;
unsigned mlen = mag->length;
uint16_t *m = mag->data;
memset(&mm, 0, sizeof(mm));
// The Mode S preamble is made of impulses of 0.5 microseconds at
// the following time offsets:
//
// 0 - 0.5 usec: first impulse.
// 1.0 - 1.5 usec: second impulse.
// 3.5 - 4 usec: third impulse.
// 4.5 - 5 usec: last impulse.
//
// Since we are sampling at 2 Mhz every sample in our magnitude vector
// is 0.5 usec, so the preamble will look like this, assuming there is
// an impulse at offset 0 in the array:
//
// 0 -----------------
// 1 -
// 2 ------------------
// 3 --
// 4 -
// 5 --
// 6 -
// 7 ------------------
// 8 --
// 9 -------------------
//
for (j = 0; j < mlen; j++) {
int high, i, errors, errors56, errorsTy;
uint16_t *pPreamble, *pPayload, *pPtr;
uint8_t theByte, theErrs;
int msglen, scanlen;
uint32_t sigLevel, noiseLevel;
uint16_t snr;
int message_ok;
pPreamble = &m[j];
pPayload = &m[j+MODES_PREAMBLE_SAMPLES];
// Rather than clear the whole mm structure, just clear the parts which are required. The clear
// is required for every bit of the input stream, and we don't want to be memset-ing the whole
// modesMessage structure two million times per second if we don't have to..
mm.bFlags =
mm.correctedbits = 0;
if (!use_correction) // This is not a re-try with phase correction
{ // so try to find a new preamble
if (Modes.mode_ac)
{
int ModeA = detectModeA(pPreamble, &mm);
if (ModeA) // We have found a valid ModeA/C in the data
{
mm.timestampMsg = mag->sampleTimestamp + ((j+1) * 6);
// compute message receive time as block-start-time + difference in the 12MHz clock
mm.sysTimestampMsg = mag->sysTimestamp; // start of block time
mm.sysTimestampMsg.tv_nsec += receiveclock_ns_elapsed(mag->sampleTimestamp, mm.timestampMsg);
normalize_timespec(&mm.sysTimestampMsg);
// Decode the received message
decodeModeAMessage(&mm, ModeA);
// Pass data to the next layer
useModesMessage(&mm);
j += MODEAC_MSG_SAMPLES;
Modes.stats_current.demod_modeac++;
continue;
}
}
// First check of relations between the first 10 samples
// representing a valid preamble. We don't even investigate further
// if this simple test is not passed
if (!(pPreamble[0] > pPreamble[1] &&
pPreamble[1] < pPreamble[2] &&
pPreamble[2] > pPreamble[3] &&
pPreamble[3] < pPreamble[0] &&
pPreamble[4] < pPreamble[0] &&
pPreamble[5] < pPreamble[0] &&
pPreamble[6] < pPreamble[0] &&
pPreamble[7] > pPreamble[8] &&
pPreamble[8] < pPreamble[9] &&
pPreamble[9] > pPreamble[6]))
{
if (Modes.debug & MODES_DEBUG_NOPREAMBLE &&
*pPreamble > MODES_DEBUG_NOPREAMBLE_LEVEL)
dumpRawMessage("Unexpected ratio among first 10 samples", msg, m, j);
continue;
}
// The samples between the two spikes must be < than the average
// of the high spikes level. We don't test bits too near to
// the high levels as signals can be out of phase so part of the
// energy can be in the near samples
high = (pPreamble[0] + pPreamble[2] + pPreamble[7] + pPreamble[9]) / 6;
if (pPreamble[4] >= high ||
pPreamble[5] >= high)
{
if (Modes.debug & MODES_DEBUG_NOPREAMBLE &&
*pPreamble > MODES_DEBUG_NOPREAMBLE_LEVEL)
dumpRawMessage("Too high level in samples between 3 and 6", msg, m, j);
continue;
}
// Similarly samples in the range 11-14 must be low, as it is the
// space between the preamble and real data. Again we don't test
// bits too near to high levels, see above
if (pPreamble[11] >= high ||
pPreamble[12] >= high ||
pPreamble[13] >= high ||
pPreamble[14] >= high)
{
if (Modes.debug & MODES_DEBUG_NOPREAMBLE &&
*pPreamble > MODES_DEBUG_NOPREAMBLE_LEVEL)
dumpRawMessage("Too high level in samples between 10 and 15", msg, m, j);
continue;
}
Modes.stats_current.demod_preambles++;
}
else {
// If the previous attempt with this message failed, retry using
// magnitude correction
// Make a copy of the Payload, and phase correct the copy
memcpy(aux, &pPreamble[-1], sizeof(aux));
applyPhaseCorrection(&aux[1]);
pPayload = &aux[1 + MODES_PREAMBLE_SAMPLES];
// TODO ... apply other kind of corrections
}
// Decode all the next 112 bits, regardless of the actual message
// size. We'll check the actual message type later
pMsg = &msg[0];
pPtr = pPayload;
theByte = 0;
theErrs = 0; errorsTy = 0;
errors = 0; errors56 = 0;
// We should have 4 'bits' of 0/1 and 1/0 samples in the preamble,
// so include these in the signal strength
sigLevel = pPreamble[0] + pPreamble[2] + pPreamble[7] + pPreamble[9];
noiseLevel = pPreamble[1] + pPreamble[3] + pPreamble[4] + pPreamble[6] + pPreamble[8];
msglen = scanlen = MODES_LONG_MSG_BITS;
for (i = 0; i < scanlen; i++) {
uint32_t a = *pPtr++;
uint32_t b = *pPtr++;
if (a > b)
{theByte |= 1; if (i < 56) { sigLevel += a; noiseLevel += b; }}
else if (a < b)
{/*theByte |= 0;*/ if (i < 56) { sigLevel += b; noiseLevel += a; }}
else {
if (i < 56) { sigLevel += a; noiseLevel += a; }
if (i >= MODES_SHORT_MSG_BITS) //(a == b), and we're in the long part of a frame
{errors++; /*theByte |= 0;*/}
else if (i >= 5) //(a == b), and we're in the short part of a frame
{scanlen = MODES_LONG_MSG_BITS; errors56 = ++errors;/*theByte |= 0;*/}
else if (i) //(a == b), and we're in the message type part of a frame
{errorsTy = errors56 = ++errors; theErrs |= 1; /*theByte |= 0;*/}
else //(a == b), and we're in the first bit of the message type part of a frame
{errorsTy = errors56 = ++errors; theErrs |= 1; theByte |= 1;}
}
if ((i & 7) == 7)
{*pMsg++ = theByte;}
else if (i == 4) {
msglen = modesMessageLenByType(theByte);
if (errors == 0)
{scanlen = msglen;}
}
theByte = theByte << 1;
if (i < 7)
{theErrs = theErrs << 1;}
// If we've exceeded the permissible number of encoding errors, abandon ship now
if (errors > MODES_MSG_ENCODER_ERRS) {
if (i < MODES_SHORT_MSG_BITS) {
msglen = 0;
} else if ((errorsTy == 1) && (theErrs == 0x80)) {
// If we only saw one error in the first bit of the byte of the frame, then it's possible
// we guessed wrongly about the value of the bit. We may be able to correct it by guessing
// the other way.
//
// We guessed a '1' at bit 7, which is the DF length bit == 112 Bits.
// Inverting bit 7 will change the message type from a long to a short.
// Invert the bit, cross your fingers and carry on.
msglen = MODES_SHORT_MSG_BITS;
msg[0] ^= theErrs; errorsTy = 0;
errors = errors56; // revert to the number of errors prior to bit 56
} else if (i < MODES_LONG_MSG_BITS) {
msglen = MODES_SHORT_MSG_BITS;
errors = errors56;
} else {
msglen = MODES_LONG_MSG_BITS;
}
break;
}
}
// Ensure msglen is consistent with the DF type
if (msglen > 0) {
i = modesMessageLenByType(msg[0] >> 3);
if (msglen > i) {msglen = i;}
else if (msglen < i) {msglen = 0;}
}
//
// If we guessed at any of the bits in the DF type field, then look to see if our guess was sensible.
// Do this by looking to see if the original guess results in the DF type being one of the ICAO defined
// message types. If it isn't then toggle the guessed bit and see if this new value is ICAO defined.
// if the new value is ICAO defined, then update it in our message.
if ((msglen) && (errorsTy == 1) && (theErrs & 0x78)) {
// We guessed at one (and only one) of the message type bits. See if our guess is "likely"
// to be correct by comparing the DF against a list of known good DF's
int thisDF = ((theByte = msg[0]) >> 3) & 0x1f;
uint32_t validDFbits = 0x017F0831; // One bit per 32 possible DF's. Set bits 0,4,5,11,16.17.18.19,20,21,22,24
uint32_t thisDFbit = (1 << thisDF);
if (0 == (validDFbits & thisDFbit)) {
// The current DF is not ICAO defined, so is probably an errors.
// Toggle the bit we guessed at and see if the resultant DF is more likely
theByte ^= theErrs;
thisDF = (theByte >> 3) & 0x1f;
thisDFbit = (1 << thisDF);
// if this DF any more likely?
if (validDFbits & thisDFbit) {
// Yep, more likely, so update the main message
msg[0] = theByte;
errors--; // decrease the error count so we attempt to use the modified DF.
}
}
}
// snr = 5 * 20log10(sigLevel / noiseLevel) (in units of 0.2dB)
// = 100log10(sigLevel) - 100log10(noiseLevel)
while (sigLevel > 65535 || noiseLevel > 65535) {
sigLevel >>= 1;
noiseLevel >>= 1;
}
snr = Modes.log10lut[sigLevel] - Modes.log10lut[noiseLevel];
// When we reach this point, if error is small, and the signal strength is large enough
// we may have a Mode S message on our hands. It may still be broken and the CRC may not
// be correct, but this can be handled by the next layer.
if ( (msglen)
&& ((2 * snr) > (int) (MODES_MSG_SQUELCH_DB * 10))
&& (errors <= MODES_MSG_ENCODER_ERRS) ) {
int result;
// Set initial mm structure details
mm.timestampMsg = mag->sampleTimestamp + (j*6);
// compute message receive time as block-start-time + difference in the 12MHz clock
mm.sysTimestampMsg = mag->sysTimestamp; // start of block time
mm.sysTimestampMsg.tv_nsec += receiveclock_ns_elapsed(mag->sampleTimestamp, mm.timestampMsg);
normalize_timespec(&mm.sysTimestampMsg);
mm.signalLevel = (365.0*60 + sigLevel + noiseLevel) * (365.0*60 + sigLevel + noiseLevel) / MAX_POWER / 60 / 60;
// Decode the received message
result = decodeModesMessage(&mm, msg);
if (result < 0) {
message_ok = 0;
if (result == -1)
Modes.stats_current.demod_rejected_unknown_icao++;
else
Modes.stats_current.demod_rejected_bad++;
} else {
message_ok = 1;
Modes.stats_current.demod_accepted[mm.correctedbits]++;
}
// Update statistics
// Output debug mode info if needed
if (use_correction) {
if (Modes.debug & MODES_DEBUG_DEMOD)
dumpRawMessage("Demodulated with 0 errors", msg, m, j);
else if (Modes.debug & MODES_DEBUG_BADCRC &&
mm.msgtype == 17 &&
(!message_ok || mm.correctedbits > 0))
dumpRawMessage("Decoded with bad CRC", msg, m, j);
else if (Modes.debug & MODES_DEBUG_GOODCRC &&
message_ok &&
mm.correctedbits == 0)
dumpRawMessage("Decoded with good CRC", msg, m, j);
}
// Skip this message if we are sure it's fine
if (message_ok) {
j += (MODES_PREAMBLE_US+msglen)*2 - 1;
// Pass data to the next layer
useModesMessage(&mm);
}
} else {
message_ok = 0;
if (Modes.debug & MODES_DEBUG_DEMODERR && use_correction) {
printf("The following message has %d demod errors\n", errors);
dumpRawMessage("Demodulated with errors", msg, m, j);
}
}
// Retry with phase correction if enabled, necessary and possible.
if (Modes.phase_enhance && (!message_ok || mm.correctedbits > 0) && !use_correction && j && detectOutOfPhase(pPreamble)) {
use_correction = 1; j--;
} else {
use_correction = 0;
}
}
}

29
demod_2000.h
View file

@ -1,29 +0,0 @@
// Part of dump1090, a Mode S message decoder for RTLSDR devices.
//
// demod_2000.h: 2MHz Mode S demodulator prototypes.
//
// Copyright (c) 2014,2015 Oliver Jowett <oliver@mutability.co.uk>
//
// This file is free software: you may copy, redistribute 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 file 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/>.
#ifndef DUMP1090_DEMOD_2000_H
#define DUMP1090_DEMOD_2000_H
#include <stdint.h>
struct mag_buf;
void demodulate2000(struct mag_buf *mag);
#endif

49
demod_2400.c
View file

@ -118,33 +118,6 @@ static inline int correlate_check_4(uint16_t *m) {
abs(correlate_phase2(&m[10]));
}
// Work out the best phase offset to use for the given message.
static int best_phase(uint16_t *m) {
int test;
int best = -1;
int bestval = (m[0] + m[1] + m[2] + m[3] + m[4] + m[5]); // minimum correlation quality we will accept
// empirical testing suggests that 4..8 is the best range to test for here
// (testing a wider range runs the danger of picking the wrong phase for
// a message that would otherwise be successfully decoded - the correlation
// functions can match well with a one symbol / half bit offset)
// this is consistent with the peak detection which should produce
// the first data symbol with phase offset 4..8
test = correlate_check_4(&m[0]);
if (test > bestval) { bestval = test; best = 4; }
test = correlate_check_0(&m[1]);
if (test > bestval) { bestval = test; best = 5; }
test = correlate_check_1(&m[1]);
if (test > bestval) { bestval = test; best = 6; }
test = correlate_check_2(&m[1]);
if (test > bestval) { bestval = test; best = 7; }
test = correlate_check_3(&m[1]);
if (test > bestval) { bestval = test; best = 8; }
return best;
}
//
// Given 'mlen' magnitude samples in 'm', sampled at 2.4MHz,
// try to demodulate some Mode S messages.
@ -170,7 +143,7 @@ void demodulate2400(struct mag_buf *mag)
uint16_t *preamble = &m[j];
int high;
uint32_t base_signal, base_noise;
int initial_phase, first_phase, last_phase, try_phase;
int try_phase;
int msglen;
// Look for a message starting at around sample 0 with phase offset 3..7
@ -252,22 +225,10 @@ void demodulate2400(struct mag_buf *mag)
continue;
}
if (Modes.phase_enhance) {
first_phase = 4;
last_phase = 8; // try all phases
} else {
// Crosscorrelate against the first few bits to find a likely phase offset
initial_phase = best_phase(&preamble[19]);
if (initial_phase < 0) {
continue; // nothing satisfactory
}
first_phase = last_phase = initial_phase; // try only the phase we think it is
}
// try all phases
Modes.stats_current.demod_preambles++;
bestmsg = NULL; bestscore = -2; bestphase = -1;
for (try_phase = first_phase; try_phase <= last_phase; ++try_phase) {
for (try_phase = 4; try_phase <= 8; ++try_phase) {
uint16_t *pPtr;
int phase, i, score, bytelen;
@ -462,8 +423,8 @@ void demodulate2400(struct mag_buf *mag)
useModesMessage(&mm);
}
/* update noise power if measured */
if (Modes.measure_noise) {
/* update noise power */
{
double sum_signal_power = sum_scaled_signal_power / 65535.0 / 65535.0;
Modes.stats_current.noise_power_sum += (mag->total_power - sum_signal_power);
Modes.stats_current.noise_power_count += mag->length;

33
dump1090.c
View file

@ -167,10 +167,7 @@ void modesInit(void) {
pthread_mutex_init(&Modes.data_mutex,NULL);
pthread_cond_init(&Modes.data_cond,NULL);
if (Modes.oversample)
Modes.sample_rate = 2400000.0;
else
Modes.sample_rate = 2000000.0;
Modes.sample_rate = 2400000.0;
// Allocate the various buffers used by Modes
Modes.trailing_samples = (MODES_PREAMBLE_US + MODES_LONG_MSG_BITS + 16) * 1e-6 * Modes.sample_rate;
@ -256,7 +253,6 @@ void modesInit(void) {
Modes.converter_function = init_converter(Modes.input_format,
Modes.sample_rate,
Modes.dc_filter,
Modes.measure_noise, /* total power is interesting if we want noise */
&Modes.converter_state);
if (!Modes.converter_function) {
fprintf(stderr, "Can't initialize sample converter, giving up.\n");
@ -702,7 +698,6 @@ void showHelp(void) {
"--fix Enable single-bits error correction using CRC\n"
"--no-fix Disable single-bits error correction using CRC\n"
"--no-crc-check Disable messages with broken CRC (discouraged)\n"
"--phase-enhance Enable phase enhancement\n"
#ifdef ALLOW_AGGRESSIVE
"--aggressive More CPU for more messages (two bits fixes, ...)\n"
#endif
@ -722,9 +717,7 @@ void showHelp(void) {
"--write-json <dir> Periodically write json output to <dir> (for serving by a separate webserver)\n"
"--write-json-every <t> Write json output every t seconds (default 1)\n"
"--json-location-accuracy <n> Accuracy of receiver location in json metadata: 0=no location, 1=approximate, 2=exact\n"
"--oversample Use the 2.4MHz demodulator\n"
"--dcfilter Apply a 1Hz DC filter to input data (requires lots more CPU)\n"
"--measure-noise Measure noise power (requires slightly more CPU)\n"
"--help Show this help\n"
"\n"
"Debug mode flags: d = Log frames decoded with errors\n"
@ -956,7 +949,7 @@ int main(int argc, char **argv) {
} else if (!strcmp(argv[j],"--dcfilter")) {
Modes.dc_filter = 1;
} else if (!strcmp(argv[j],"--measure-noise")) {
Modes.measure_noise = 1;
// Ignored
} else if (!strcmp(argv[j],"--fix")) {
Modes.nfix_crc = 1;
} else if (!strcmp(argv[j],"--no-fix")) {
@ -964,7 +957,7 @@ int main(int argc, char **argv) {
} else if (!strcmp(argv[j],"--no-crc-check")) {
Modes.check_crc = 0;
} else if (!strcmp(argv[j],"--phase-enhance")) {
Modes.phase_enhance = 1;
// Ignored, always enabled
} else if (!strcmp(argv[j],"--raw")) {
Modes.raw = 1;
} else if (!strcmp(argv[j],"--net")) {
@ -1080,7 +1073,7 @@ int main(int argc, char **argv) {
Modes.interactive = 1;
Modes.interactive_rtl1090 = 1;
} else if (!strcmp(argv[j],"--oversample")) {
Modes.oversample = 1;
// Ignored
} else if (!strcmp(argv[j], "--html-dir") && more) {
Modes.html_dir = strdup(argv[++j]);
#ifndef _WIN32
@ -1166,6 +1159,8 @@ int main(int argc, char **argv) {
usleep(100000);
}
} else {
int watchdogCounter = 10; // about 1 second
// Create the thread that will read the data from the device.
pthread_mutex_lock(&Modes.data_mutex);
pthread_create(&Modes.reader_thread, NULL, readerThreadEntryPoint, NULL);
@ -1207,13 +1202,9 @@ int main(int argc, char **argv) {
// stuff at the same time.
pthread_mutex_unlock(&Modes.data_mutex);
if (Modes.oversample) {
demodulate2400(buf);
if (Modes.mode_ac) {
demodulate2400AC(buf);
}
} else {
demodulate2000(buf);
demodulate2400(buf);
if (Modes.mode_ac) {
demodulate2400AC(buf);
}
Modes.stats_current.samples_processed += buf->length;
@ -1225,9 +1216,14 @@ int main(int argc, char **argv) {
Modes.first_filled_buffer = (Modes.first_filled_buffer + 1) % MODES_MAG_BUFFERS;
pthread_cond_signal(&Modes.data_cond);
pthread_mutex_unlock(&Modes.data_mutex);
watchdogCounter = 10;
} else {
// Nothing to process this time around.
pthread_mutex_unlock(&Modes.data_mutex);
if (--watchdogCounter <= 0) {
log_with_timestamp("No data received from the dongle for a long time, it may have wedged");
watchdogCounter = 600;
}
}
start_cpu_timing(&start_time);
@ -1239,6 +1235,7 @@ int main(int argc, char **argv) {
pthread_mutex_unlock(&Modes.data_mutex);
log_with_timestamp("Waiting for receive thread termination");
pthread_join(Modes.reader_thread,NULL); // Wait on reader thread exit
pthread_cond_destroy(&Modes.data_cond); // Thread cleanup - only after the reader thread is dead!
pthread_mutex_destroy(&Modes.data_mutex);

8
dump1090.h
View file

@ -90,8 +90,6 @@ typedef struct rtlsdr_dev rtlsdr_dev_t;
// ============================= #defines ===============================
#define MODES_DEFAULT_PPM 52
#define MODES_DEFAULT_RATE 2000000
#define MODES_OVERSAMPLE_RATE 2400000
#define MODES_DEFAULT_FREQ 1090000000
#define MODES_DEFAULT_WIDTH 1000
#define MODES_DEFAULT_HEIGHT 700
@ -104,8 +102,6 @@ typedef struct rtlsdr_dev rtlsdr_dev_t;
#define MODES_MSG_SQUELCH_DB 4.0 // Minimum SNR, in dB
#define MODES_MSG_ENCODER_ERRS 3 // Maximum number of encoding errors
#define MODES_MAX_PHASE_STATS 10
#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
@ -213,7 +209,6 @@ typedef struct rtlsdr_dev rtlsdr_dev_t;
#include "anet.h"
#include "net_io.h"
#include "crc.h"
#include "demod_2000.h"
#include "demod_2400.h"
#include "stats.h"
#include "cpr.h"
@ -255,7 +250,6 @@ struct { // Internal state
// Sample conversion
int dc_filter; // should we apply a DC filter?
int measure_noise; // should we measure noise power?
iq_convert_fn converter_function;
struct converter_state *converter_state;
@ -283,8 +277,6 @@ struct { // Internal state
// Configuration
char *filename; // Input form file, --ifile option
int oversample;
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

4
stats.c
View file

@ -90,7 +90,7 @@ void display_stats(struct stats *st) {
printf(" %u accepted with %d-bit error repaired\n", st->demod_accepted[j], j);
if (st->noise_power_sum > 0 && st->noise_power_count > 0) {
printf(" %.1f dBFS noise floor\n",
printf(" %.1f dBFS noise power\n",
10 * log10(st->noise_power_sum / st->noise_power_count));
}
@ -279,7 +279,7 @@ void add_stats(const struct stats *st1, const struct stats *st2, struct stats *t
add_timespecs(&st1->reader_cpu, &st2->reader_cpu, &target->reader_cpu);
add_timespecs(&st1->background_cpu, &st2->background_cpu, &target->background_cpu);
// noise floor:
// noise power:
target->noise_power_sum = st1->noise_power_sum + st2->noise_power_sum;
target->noise_power_count = st1->noise_power_count + st2->noise_power_count;