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Signal power level. 

From @tomcourt
pull/58/head
Christopher Young 2015-09-21 15:44:08 -04:00
rodzic 9e78dddab7
commit e434c50e86
1 zmienionych plików z 39 dodań i 9 usunięć
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48
dump978/dump978.c
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@ -33,7 +33,8 @@ static void make_atan2_table(void);
#ifndef BUILD_LIB
static void read_from_stdin(void);
#endif
static int process_buffer(uint16_t *phi, int len, uint64_t offset);
static int process_buffer(uint16_t *phi, uint16_t *raw, int len,
uint64_t offset);
static int demod_adsb_frame(uint16_t *phi, uint8_t *to, int *rs_errors);
static int demod_uplink_frame(uint16_t *phi, uint8_t *to, int *rs_errors);
static void demod_frame(uint16_t *phi, uint8_t *frame, int bytes,
@ -77,6 +78,8 @@ void Dump978Init(CallBack cb) {
}
#endif
static int signal_strength = 0;
static void dump_raw_message(char updown, uint8_t *data, int len,
int rs_errors) {
#ifndef BUILD_LIB
@ -89,6 +92,7 @@ static void dump_raw_message(char updown, uint8_t *data, int len,
if (rs_errors)
fprintf(stdout, ";rs=%d", rs_errors);
fprintf(stdout, ";ss=%d", signal_strength);
fprintf(stdout, ";\n");
#else
userCB(updown, data, len);
@ -109,6 +113,8 @@ static void handle_uplink_frame(uint64_t timestamp, uint8_t *frame, int rs) {
uint16_t iqphase[65536]; // contains value [0..65536) -> [0, 2*pi)
uint16_t iqamplitude[65536]; // contains value [0..65536) -> [0, 1000*sqrt(2))
void make_atan2_table(void) {
unsigned i, q;
union {
@ -124,25 +130,40 @@ void make_atan2_table(void) {
M_PI; // atan2 returns [-pi..pi], normalize to [0..2*pi]
double scaled_ang = round(32768 * ang / M_PI);
double amp = sqrt(d_i * d_i + d_q * d_q);
uint16_t scaled_amp = amp * 1000.0 / 127.5 + .5;
u.iq[0] = i;
u.iq[1] = q;
iqphase[u.iq16] =
(scaled_ang < 0 ? 0 : scaled_ang > 65535 ? 65535
: (uint16_t)scaled_ang);
iqamplitude[u.iq16] = scaled_amp;
}
}
}
static void convert_to_phi(uint16_t *buffer, int n) {
static void convert_to_phi(uint16_t *dest, uint16_t *src, int n) {
int i;
for (i = 0; i < n; ++i)
buffer[i] = iqphase[buffer[i]];
dest[i] = iqphase[src[i]];
}
static void calc_power(uint16_t *samples, int len) {
long avg = 0;
int n = len;
while (n--) {
avg += iqamplitude[*samples++];
}
signal_strength = (avg + len / 2) / len;
}
#ifndef BUILD_LIB
void read_from_stdin(void) {
char buffer[65536 * 2];
uint16_t phi[65536];
int n;
int used = 0;
uint64_t offset = 0;
@ -150,14 +171,16 @@ void read_from_stdin(void) {
while ((n = read(0, buffer + used, sizeof(buffer) - used)) > 0) {
int processed;
convert_to_phi((uint16_t *)(buffer + (used & ~1)), ((used & 1) + n) / 2);
convert_to_phi(phi + used / 2, (uint16_t *)(buffer + (used & ~1)),
((used & 1) + n) / 2);
used += n;
processed = process_buffer((uint16_t *)buffer, used / 2, offset);
processed = process_buffer(phi, (uint16_t *)buffer, used / 2, offset);
used -= processed * 2;
offset += processed;
if (used > 0) {
memmove(buffer, buffer + processed * 2, used);
memmove(phi, phi + processed, used);
}
}
}
@ -176,10 +199,13 @@ int process_data(char *data, int dlen) {
n = (sizeof(buffer) - used) >= dlen ? dlen : (sizeof(buffer) - used);
memcpy(buffer + used, data + doffset, n);
convert_to_phi((uint16_t *)(buffer + (used & ~1)), ((used & 1) + n) / 2);
// convert in place for lib
convert_to_phi((uint16_t *)(buffer + (used & ~1)),
(uint16_t *)(buffer + (used & ~1)), ((used & 1) + n) / 2);
used += n;
processed = process_buffer((uint16_t *)buffer, used / 2, offset);
processed = process_buffer((uint16_t *)buffer, (uint16_t *)buffer, used / 2,
offset);
used -= processed * 2;
offset += processed;
if (used > 0) {
@ -307,7 +333,7 @@ int check_sync_word(uint16_t *phi, uint64_t pattern, int16_t *center) {
#define SYNC_MASK ((((uint64_t)1) << SYNC_BITS) - 1)
int process_buffer(uint16_t *phi, int len, uint64_t offset) {
int process_buffer(uint16_t *phi, uint16_t *raw, int len, uint64_t offset) {
uint64_t sync0 = 0, sync1 = 0;
int lenbits;
int bit;
@ -366,10 +392,12 @@ int process_buffer(uint16_t *phi, int len, uint64_t offset) {
skip_0 = demod_adsb_frame(phi + index, demod_buf_a, &rs_0);
skip_1 = demod_adsb_frame(phi + index + 1, demod_buf_b, &rs_1);
if (skip_0 && rs_0 <= rs_1) {
calc_power(raw + index, skip_0 * 2);
handle_adsb_frame(offset + index, demod_buf_a, rs_0);
bit = startbit + skip_0;
continue;
} else if (skip_1 && rs_1 <= rs_0) {
calc_power(raw + index + 1, skip_1 * 2);
handle_adsb_frame(offset + index + 1, demod_buf_b, rs_1);
bit = startbit + skip_1;
continue;
@ -391,10 +419,12 @@ int process_buffer(uint16_t *phi, int len, uint64_t offset) {
skip_0 = demod_uplink_frame(phi + index, demod_buf_a, &rs_0);
skip_1 = demod_uplink_frame(phi + index + 1, demod_buf_b, &rs_1);
if (skip_0 && rs_0 <= rs_1) {
calc_power(raw + index, skip_0 * 2);
handle_uplink_frame(offset + index, demod_buf_a, rs_0);
bit = startbit + skip_0;
continue;
} else if (skip_1 && rs_1 <= rs_0) {
calc_power(raw + index, skip_1 * 2);
handle_uplink_frame(offset + index + 1, demod_buf_b, rs_1);
bit = startbit + skip_1;
continue;
@ -482,4 +512,4 @@ static int demod_uplink_frame(uint16_t *phi, uint8_t *to, int *rs_errors) {
return (UPLINK_FRAME_BITS + SYNC_BITS);
else
return 0;
}
}