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ADS-B Demodulator updates.

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Add OpenSky Network aircraft database support, for information about
aircraft model, owner, registration.
Add airline logos and country & military flags for display in the table.
Add OurAirports airport database support, to allow airports and ATC
frequencies to be displayed on the map.
Allow ATC frequency to be tuned by clicking on the map.
Add support for displaying flight paths on the map.
Allow columns in table to be rearranged and hidden.
Allow rows in table to be sorted by clicking on header.
Allow switching units from ft, kn, ft/min to m, kph, m/s
Allow aircraft timeout to be set by the user.
Allow font used for the table to be set by the user.
Add optional display of demodulator statistics.
Support multithreading in demodulator to reduce FIFO overflows.
Add support for demodulating all Mode-S frames and feeding them.
Add support for feeding in Beast hex format.
Allow option of correlating against full preamble or partial preamble.
Supporting highlighting of an aircraft in the table by selecting it on
the map.
Use difference of zeros and ones correlation, rather than absolute
threshold, to better account for varying conditions and make the
threshold easier to set.
Enable anti-aliasing for text on the map.
Improve CRC performance by 5x-10x.
Add HttpDownloadManager class to support downloading of files from the
web to disk.
This commit is contained in:
Jon Beniston
2020-11-06 12:18:55 +00:00
parent c5a36c48a0
commit 72e4e684e2
1245 changed files with 5950 additions and 827 deletions
Download Patch File Download Diff File Expand all files Collapse all files
sdrbase/util/crc.cpp
+42 -14
View File
@@ -34,27 +34,55 @@ void crc::calculate(uint32_t data, int data_bits)
{
uint32_t tmp;
uint32_t mask;
uint32_t msb;
int bit, i;
// Reverse data order.
if (m_msb_first)
data = reverse (data, data_bits);
// Compute CRC.
tmp = m_crc;
for (i = 0; i < data_bits; i++) {
bit = ((data >> i) & 1) ^ (tmp & 1);
if (bit)
tmp = (tmp >> 1) ^ m_polynomial_rev;
else
tmp = tmp >> 1;
{
mask = (1 << m_poly_bits) - 1;
msb = 1 << (m_poly_bits - 1);
tmp = m_crc ^ (data << (m_poly_bits - 8));
for (i = 0; i < data_bits; i++)
{
if (tmp & msb)
tmp = (tmp << 1) ^ m_polynomial;
else
tmp = tmp << 1;
tmp = tmp & mask;
}
m_crc = tmp;
}
else
{
tmp = m_crc;
for (i = 0; i < data_bits; i++) {
bit = ((data >> i) & 1) ^ (tmp & 1);
if (bit)
tmp = (tmp >> 1) ^ m_polynomial_rev;
else
tmp = tmp >> 1;
}
m_crc = tmp;
}
m_crc = tmp;
}
// Calculate CRC for specified array
void crc::calculate(const uint8_t *data, int length)
{
for(int i = 0; i < length; i++)
calculate(data[i], 8);
int i;
uint32_t mask1;
uint32_t mask2;
if (m_msb_first)
{
mask1 = (1 << m_poly_bits) - 1;
mask2 = 0xff << (m_poly_bits - 8);
for (i = 0; i < length; i++)
m_crc = mask1 & ((m_crc << 8) ^ m_lut[data[i] ^ ((m_crc & mask2) >> (m_poly_bits-8))]);
}
else
{
for (i = 0; i < length; i++)
m_crc = (m_crc >> 8) ^ m_lut[data[i] ^ (m_crc & 0xff)];
}
}