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Add support for arbitraty descrambling polynomials on the FSK receiver

This commit is contained in:
Manolis Surligas 2017-04-15 01:23:47 +03:00
parent a94cf99a20
commit a8d0eae736
4 changed files with 252 additions and 211 deletions
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23
grc/satellites/upsat/satnogs_upsat_fsk_frame_acquisition.xml
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@ -3,7 +3,7 @@
<name>UPSAT FSK Frame Acquisition</name>
<key>satnogs_upsat_fsk_frame_acquisition</key>
<import>import satnogs</import>
<make>satnogs.upsat_fsk_frame_acquisition($preamble, $sync_word, $whitening, $manchester, $check_crc, $ax_25)</make>
<make>satnogs.upsat_fsk_frame_acquisition($preamble, $sync_word, $whitening, $manchester, $check_crc, $ax_25, $whitening_mask, $whitening_seed, $whitening_order)</make>
<param>
<name>Frame Preamble</name>
@ -72,6 +72,27 @@
<key>True</key>
</option>
</param>
<param>
<name>Whitening mask</name>
<key>whitening_mask</key>
<value>0x1001</value>
<type>int</type>
</param>
<param>
<name>Whitening seed</name>
<key>whitening_seed</key>
<value>0x1FF</value>
<type>int</type>
</param>
<param>
<name>Whitening order</name>
<key>whitening_order</key>
<value>17</value>
<type>int</type>
</param>
<sink>
<name>in</name>

12
include/satnogs/upsat_fsk_frame_acquisition.h
View File

@ -2,7 +2,8 @@
/*
* gr-satnogs: SatNOGS GNU Radio Out-Of-Tree Module
*
* Copyright (C) 2016, Libre Space Foundation <http://librespacefoundation.org/>
* Copyright (C) 2016,2017,
* Libre Space Foundation <http://librespacefoundation.org/>
*
* 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
@ -63,12 +64,19 @@ namespace gr
* encoded payload. Prior producing the payload, AX.25 decoding
* will be performed. If set to false, the payload will be pushed
* as it is.
*
* @param whitening_mask the polynomial of the scrambler
* @param whitening_seed the initial seed of the scrambler
* @param whitening_order the size of the scrambler's LFSR
*/
static sptr
make (const std::vector<uint8_t> &preamble,
const std::vector<uint8_t> &sync_word, bool whitening = false,
bool manchester = false, bool check_crc = true,
bool ax25_format = false);
bool ax25_format = false,
uint32_t whitening_mask = 0x1001,
uint32_t whitening_seed = 0x1FF,
uint32_t whitening_order = 17);
};
} // namespace satnogs

399
lib/upsat_fsk_frame_acquisition_impl.cc
View File

@ -2,7 +2,8 @@
/*
* gr-satnogs: SatNOGS GNU Radio Out-Of-Tree Module
*
* Copyright (C) 2016, Libre Space Foundation <http://librespacefoundation.org/>
* Copyright (C) 2016,2017,
* Libre Space Foundation <http://librespacefoundation.org/>
*
* 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
@ -36,65 +37,70 @@ namespace gr
upsat_fsk_frame_acquisition::sptr
upsat_fsk_frame_acquisition::make (const std::vector<uint8_t> &preamble,
const std::vector<uint8_t> &sync_word,
bool whitening, bool manchester,
bool check_crc,
bool ax25_format)
const std::vector<uint8_t> &sync_word,
bool whitening, bool manchester,
bool check_crc, bool ax25_format,
uint32_t whitening_mask,
uint32_t whitening_seed,
uint32_t whitening_order)
{
return gnuradio::get_initial_sptr (
new upsat_fsk_frame_acquisition_impl (preamble, sync_word, whitening,
manchester, check_crc,
ax25_format));
new upsat_fsk_frame_acquisition_impl (preamble, sync_word, whitening,
manchester, check_crc,
ax25_format, whitening_mask,
whitening_seed,
whitening_order));
}
/*
* The private constructor
*/
upsat_fsk_frame_acquisition_impl::upsat_fsk_frame_acquisition_impl (
const std::vector<uint8_t> &preamble,
const std::vector<uint8_t> &sync_word, bool whitening, bool manchester,
bool check_crc, bool ax25_format) :
gr::sync_block ("upsat_fsk_frame_acquisition",
gr::io_signature::make (1, 1, sizeof(float)),
gr::io_signature::make (0, 0, 0)),
d_preamble (preamble),
d_preamble_len (preamble.size ()),
d_sync_word (sync_word),
d_sync_word_len (sync_word.size ()),
/*
* Preamble is used only for AGC. The true synchronization is
* performed using the SYNC word. For this reason if some preamble
* symbols are retrieved, the algorithm should immediately start
* searching for the SYNC word.
*/
d_search_for_sync_thrhld(d_preamble_len / 3),
d_whitening(whitening),
d_manchester(manchester),
d_check_crc(check_crc),
d_is_ax25(ax25_format),
d_state (SEARCHING),
d_shifting_byte (0x0),
d_decoded_bytes (0),
d_decoded_bits (0),
d_frame_len (0),
d_descrambler(0x1001, 0x1FF, 17)
const std::vector<uint8_t> &preamble,
const std::vector<uint8_t> &sync_word, bool whitening, bool manchester,
bool check_crc, bool ax25_format, uint32_t whitening_mask,
uint32_t whitening_seed, uint32_t whitening_order) :
gr::sync_block ("upsat_fsk_frame_acquisition",
gr::io_signature::make (1, 1, sizeof(float)),
gr::io_signature::make (0, 0, 0)),
d_preamble (preamble),
d_preamble_len (preamble.size ()),
d_sync_word (sync_word),
d_sync_word_len (sync_word.size ()),
/*
* Preamble is used only for AGC. The true synchronization is
* performed using the SYNC word. For this reason if some preamble
* symbols are retrieved, the algorithm should immediately start
* searching for the SYNC word.
*/
d_search_for_sync_thrhld (d_preamble_len / 3),
d_whitening (whitening),
d_manchester (manchester),
d_check_crc (check_crc),
d_is_ax25 (ax25_format),
d_state (SEARCHING),
d_shifting_byte (0x0),
d_decoded_bytes (0),
d_decoded_bits (0),
d_frame_len (0),
d_descrambler (whitening_mask, whitening_seed, whitening_order)
{
size_t i;
message_port_register_out (pmt::mp ("pdu"));
if (d_preamble_len < 3) {
throw std::invalid_argument ("Preamble must be at least 2 bytes long");
throw std::invalid_argument ("Preamble must be at least 2 bytes long");
}
if (d_sync_word_len < 1) {
throw std::invalid_argument (
"Synchronization word must be at least 1 byte long");
throw std::invalid_argument (
"Synchronization word must be at least 1 byte long");
}
for(i = 1; i < d_preamble_len; i++){
if(d_preamble[i] != d_preamble[0]) {
throw std::invalid_argument (
"The preamble should contain the same bytes");
}
for (i = 1; i < d_preamble_len; i++) {
if (d_preamble[i] != d_preamble[0]) {
throw std::invalid_argument (
"The preamble should contain the same bytes");
}
}
d_pdu = new uint8_t[UPSAT_MAX_FRAME_LEN];
@ -163,7 +169,7 @@ namespace gr
upsat_fsk_frame_acquisition_impl::have_frame_len ()
{
LOG_DEBUG("Enter frame len");
d_descrambler.reset();
d_descrambler.reset ();
d_state = HAVE_FRAME_LEN;
d_decoded_bytes = 0;
d_decoded_bits = 0;
@ -184,29 +190,29 @@ namespace gr
size_t i;
uint8_t *in = d_pdu + 1;
for(i = 0; i < len_bytes; i++){
d_ax25_tmp_buf[8*i] = (in[i] >> 7) & 0x1;
d_ax25_tmp_buf[8*i + 1] = (in[i] >> 6) & 0x1;
d_ax25_tmp_buf[8*i + 2] = (in[i] >> 5) & 0x1;
d_ax25_tmp_buf[8*i + 3] = (in[i] >> 4) & 0x1;
d_ax25_tmp_buf[8*i + 4] = (in[i] >> 3) & 0x1;
d_ax25_tmp_buf[8*i + 5] = (in[i] >> 2) & 0x1;
d_ax25_tmp_buf[8*i + 6] = (in[i] >> 1) & 0x1;
d_ax25_tmp_buf[8*i + 7] = in[i] & 0x1;
for (i = 0; i < len_bytes; i++) {
d_ax25_tmp_buf[8 * i] = (in[i] >> 7) & 0x1;
d_ax25_tmp_buf[8 * i + 1] = (in[i] >> 6) & 0x1;
d_ax25_tmp_buf[8 * i + 2] = (in[i] >> 5) & 0x1;
d_ax25_tmp_buf[8 * i + 3] = (in[i] >> 4) & 0x1;
d_ax25_tmp_buf[8 * i + 4] = (in[i] >> 3) & 0x1;
d_ax25_tmp_buf[8 * i + 5] = (in[i] >> 2) & 0x1;
d_ax25_tmp_buf[8 * i + 6] = (in[i] >> 1) & 0x1;
d_ax25_tmp_buf[8 * i + 7] = in[i] & 0x1;
}
/* De-white the data if necessary */
if (d_whitening) {
d_descrambler.descramble_one_bit_per_byte (d_ax25_tmp_buf,
d_ax25_tmp_buf,
len_bytes * 8);
d_descrambler.descramble_one_bit_per_byte (d_ax25_tmp_buf,
d_ax25_tmp_buf,
len_bytes * 8);
}
}
int
upsat_fsk_frame_acquisition_impl::work (
int noutput_items, gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
int noutput_items, gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
int i;
uint16_t crc_received;
@ -215,153 +221,156 @@ namespace gr
ax25_decode_status_t status;
const float *in = (const float *) input_items[0];
for (i = 0; i < noutput_items; i++) {
slice_and_shift (in[i]);
slice_and_shift (in[i]);
switch (d_state)
{
case SEARCHING:
if (d_shifting_byte == d_preamble[0]) {
have_preamble ();
}
break;
case HAVE_PREAMBLE:
d_decoded_bits++;
switch (d_state)
{
case SEARCHING:
if (d_shifting_byte == d_preamble[0]) {
have_preamble ();
}
break;
case HAVE_PREAMBLE:
d_decoded_bits++;
if(d_decoded_bits == 8) {
d_decoded_bits = 0;
if(d_shifting_byte == d_preamble[d_decoded_bytes]){
d_decoded_bytes++;
if(d_decoded_bytes >= d_search_for_sync_thrhld){
/* End of the preamble. It's time for the sync word */
searching_sync_word();
}
}
else{
/* Reset the preamble detection */
reset_state();
}
}
break;
case SEARCHING_SYNC_WORD:
d_decoded_bits++;
if(d_shifting_byte == d_sync_word[0]){
have_sync();
break;
}
if (d_decoded_bits == 8) {
d_decoded_bits = 0;
if (d_shifting_byte == d_preamble[d_decoded_bytes]) {
d_decoded_bytes++;
if (d_decoded_bytes >= d_search_for_sync_thrhld) {
/* End of the preamble. It's time for the sync word */
searching_sync_word ();
}
}
else {
/* Reset the preamble detection */
reset_state ();
}
}
break;
case SEARCHING_SYNC_WORD:
d_decoded_bits++;
if (d_shifting_byte == d_sync_word[0]) {
have_sync ();
break;
}
if(d_decoded_bits == 8) {
d_decoded_bits = 0;
d_decoded_bytes++;
/*
* If we decoded bytes have length greater than the preamble and
* the SYNC word, we lost the frame...
*/
if (d_decoded_bytes > d_preamble_len
- d_search_for_sync_thrhld + d_sync_word_len) {
reset_state ();
}
}
break;
case HAVE_SYNC_WORD:
d_decoded_bits++;
if(d_decoded_bits == 8) {
d_decoded_bits = 0;
if(d_shifting_byte == d_sync_word[d_decoded_bytes]) {
d_decoded_bytes++;
if(d_decoded_bytes == d_sync_word_len){
have_frame_len();
}
}
else{
reset_state();
}
}
break;
case HAVE_FRAME_LEN:
d_decoded_bits++;
if(d_decoded_bits == 8) {
if (d_decoded_bits == 8) {
d_decoded_bits = 0;
d_decoded_bytes++;
/*
* If we decoded bytes have length greater than the preamble and
* the SYNC word, we lost the frame...
*/
if (d_decoded_bytes
> d_preamble_len - d_search_for_sync_thrhld
+ d_sync_word_len) {
reset_state ();
}
}
break;
case HAVE_SYNC_WORD:
d_decoded_bits++;
if (d_decoded_bits == 8) {
d_decoded_bits = 0;
if (d_shifting_byte == d_sync_word[d_decoded_bytes]) {
d_decoded_bytes++;
if (d_decoded_bytes == d_sync_word_len) {
have_frame_len ();
}
}
else {
reset_state ();
}
}
break;
case HAVE_FRAME_LEN:
d_decoded_bits++;
if (d_decoded_bits == 8) {
/* Length field has been whitened if the option is enabled */
if(d_whitening){
/* Frame length field is needed for the CRC calculation */
d_descrambler.descramble(d_pdu, &d_shifting_byte, 1);
/* CRC is not included in the frame length field, but we want it */
d_frame_len = 1 + d_pdu[0] + sizeof(uint16_t);
}
else{
/* Frame length field is needed for the CRC calculation */
d_pdu[0] = d_shifting_byte;
/* CRC is not included in the frame length field, but we want it */
d_frame_len = 1 + d_shifting_byte + sizeof(uint16_t);
}
have_payload();
}
break;
case HAVE_PAYLOAD:
d_decoded_bits++;
if (d_decoded_bits == 8) {
d_decoded_bits = 0;
d_pdu[d_decoded_bytes] = d_shifting_byte;
d_decoded_bytes++;
/* Length field has been whitened if the option is enabled */
if (d_whitening) {
/* Frame length field is needed for the CRC calculation */
d_descrambler.descramble (d_pdu, &d_shifting_byte, 1);
/* CRC is not included in the frame length field, but we want it */
d_frame_len = 1 + d_pdu[0] + sizeof(uint16_t);
}
else {
/* Frame length field is needed for the CRC calculation */
d_pdu[0] = d_shifting_byte;
/* CRC is not included in the frame length field, but we want it */
d_frame_len = 1 + d_shifting_byte + sizeof(uint16_t);
}
have_payload ();
}
break;
case HAVE_PAYLOAD:
d_decoded_bits++;
if (d_decoded_bits == 8) {
d_decoded_bits = 0;
d_pdu[d_decoded_bytes] = d_shifting_byte;
d_decoded_bytes++;
if (d_decoded_bytes == d_frame_len) {
if(d_is_ax25) {
if (d_decoded_bytes == d_frame_len) {
if (d_is_ax25) {
unpack_ax25_bytes(d_frame_len - 1);
status = ax25_decode(d_ax25_buf, &ax25_frame_len,
d_ax25_tmp_buf, (d_frame_len - 1)*8);
if(status == AX25_DEC_OK){
/* Skip the AX.25 header */
message_port_pub (
pmt::mp ("pdu"),
pmt::make_blob (d_ax25_buf + AX25_MIN_ADDR_LEN + 2,
ax25_frame_len - AX25_MIN_ADDR_LEN - 2));
}
unpack_ax25_bytes (d_frame_len - 1);
status = ax25_decode (d_ax25_buf, &ax25_frame_len,
d_ax25_tmp_buf, (d_frame_len - 1) * 8);
if (status == AX25_DEC_OK) {
/* Skip the AX.25 header */
message_port_pub (
pmt::mp ("pdu"),
pmt::make_blob (
d_ax25_buf + AX25_MIN_ADDR_LEN + 2,
ax25_frame_len - AX25_MIN_ADDR_LEN - 2));
}
/*
* We are done here. Whitening and FSK CRC is not supported
* when transmitting/receiving AX.25 frames
*/
reset_state ();
break;
}
/*
* We are done here. Whitening and FSK CRC is not supported
* when transmitting/receiving AX.25 frames
*/
reset_state ();
break;
}
if(d_whitening){
d_descrambler.descramble(d_pdu+1, d_pdu+1, d_frame_len - 1);
}
if (d_whitening) {
d_descrambler.descramble (d_pdu + 1, d_pdu + 1,
d_frame_len - 1);
}
if(!d_check_crc){
message_port_pub (
pmt::mp ("pdu"),
pmt::make_blob (d_pdu + 1,
d_frame_len - 1 - sizeof(uint16_t)));
reset_state ();
break;
}
if (!d_check_crc) {
message_port_pub (
pmt::mp ("pdu"),
pmt::make_blob (d_pdu + 1,
d_frame_len - 1 - sizeof(uint16_t)));
reset_state ();
break;
}
/* Retrieve and check the CRC */
memcpy(&crc_received, d_pdu + d_frame_len - sizeof(uint16_t),
sizeof(uint16_t));
/* The CRC is transmitted in network byte order */
crc_received = ntohs(crc_received);
crc_calc = crc16_ccitt(d_pdu, d_frame_len - sizeof(uint16_t));
if(crc_calc == crc_received) {
message_port_pub (
pmt::mp ("pdu"),
pmt::make_blob (d_pdu + 1,
d_frame_len - 1 - sizeof(uint16_t)));
}
else{
LOG_WARN("Frame with wrong CRC got 0x%x calc 0x%x",
crc_received, crc_calc);
}
reset_state ();
}
}
break;
default:
LOG_WARN("Unknown decoding state");
}
/* Retrieve and check the CRC */
memcpy (&crc_received, d_pdu + d_frame_len - sizeof(uint16_t),
sizeof(uint16_t));
/* The CRC is transmitted in network byte order */
crc_received = ntohs (crc_received);
crc_calc = crc16_ccitt (d_pdu, d_frame_len - sizeof(uint16_t));
if (crc_calc == crc_received) {
message_port_pub (
pmt::mp ("pdu"),
pmt::make_blob (d_pdu + 1,
d_frame_len - 1 - sizeof(uint16_t)));
}
else {
LOG_WARN("Frame with wrong CRC got 0x%x calc 0x%x",
crc_received, crc_calc);
}
reset_state ();
}
}
break;
default:
LOG_WARN("Unknown decoding state");
}
}
return noutput_items;

29
lib/upsat_fsk_frame_acquisition_impl.h
View File

@ -2,7 +2,8 @@
/*
* gr-satnogs: SatNOGS GNU Radio Out-Of-Tree Module
*
* Copyright (C) 2016, Libre Space Foundation <http://librespacefoundation.org/>
* Copyright (C) 2016,2017
* Libre Space Foundation <http://librespacefoundation.org/>
*
* 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
@ -39,12 +40,12 @@ namespace gr
*/
typedef enum
{
SEARCHING, //!< SEARCHING when searching for the start of the preamble
HAVE_PREAMBLE, //!< HAVE_PREAMBLE when the decoder is inside the preamble
SEARCHING_SYNC_WORD,
HAVE_SYNC_WORD, //!< HAVE_SYNC_WORD when the decoder is inside the sync word
HAVE_FRAME_LEN, //!< HAVE_FRAME_LEN when the decoder is inside the frame length field
HAVE_PAYLOAD //!< HAVE_PAYLOAD when the decoder process the palyload of the frame
SEARCHING, //!< SEARCHING when searching for the start of the preamble
HAVE_PREAMBLE, //!< HAVE_PREAMBLE when the decoder is inside the preamble
SEARCHING_SYNC_WORD,
HAVE_SYNC_WORD, //!< HAVE_SYNC_WORD when the decoder is inside the sync word
HAVE_FRAME_LEN, //!< HAVE_FRAME_LEN when the decoder is inside the frame length field
HAVE_PAYLOAD //!< HAVE_PAYLOAD when the decoder process the palyload of the frame
} decoding_state_t;
const std::vector<uint8_t> d_preamble;
@ -82,20 +83,22 @@ namespace gr
inline void
have_payload ();
inline void
unpack_ax25_bytes(size_t len_bytes);
unpack_ax25_bytes (size_t len_bytes);
public:
upsat_fsk_frame_acquisition_impl (const std::vector<uint8_t> &preamble,
const std::vector<uint8_t> &sync_word,
bool whitening, bool manchester,
bool check_crc,
bool ax25_format);
const std::vector<uint8_t> &sync_word,
bool whitening, bool manchester,
bool check_crc, bool ax25_format,
uint32_t whitening_mask,
uint32_t whitening_seed,
uint32_t whitening_order);
~upsat_fsk_frame_acquisition_impl ();
// Where all the action really happens
int
work (int noutput_items, gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items);
gr_vector_void_star &output_items);
};
} // namespace satnogs