This PR adds basic adaptive gain support, which adjusts SDR gain on the fly based on the noise & signal levels seen.
There are two control mechanisms:
Dynamic range control is enabled by the --adaptive-range option. This adjusts SDR gain to try to achieve a minimum dynamic range, regardless of the exact hardware in the RF path.
Burst (loud message) control is enabled by the --adaptive-burst option. This decreases SDR gain when undecodable loud messages are heard, allowing for better reception of nearby aircraft at the expense of range.
This is only the basic implementation - see the PR for remaining work to do.
Unfortunately limesuite doesn't seem to provide an API identifier, so
we can't detect whether LMS_PATH_AUTO is supported or not. Change the
fallback to LMS_PATH_LNAW, since that appears to work on both mini
and full-fat limesdrs.
Update all the SDR implementation to use it.
This was getting pretty ugly with code getting copy&pasted in all the SDR
implementations. Unify it all and give it a simpler API. Linked list works out
much simpler than the circular buffer. Also, simplify copying the overlap region
around by just using a separate buffer (it's only a few hundred bytes long, so
the double copy is not a big deal).
Add ability to set calibration bandwidth via input command line options.
By default the bandwidth is equal to 2.5 MHz.
Test: connect LimeSDR device, try to set different bandwidth and check
logs:
$ ./dump1090 --device-type limesdr --limesdr-bw 5000000
$ ./dump1090 --device-type limesdr --limesdr-bw 500000
Signed-off-by: Gluttton <gluttton@ukr.net>
Add ability to set LPF bandwidth via input command line options.
By default the bandwidth is equal to the default sample rate 2.4 MHz.
Test: connect LimeSDR device, try to set different bandwidth and check
logs:
$ ./dump1090 --device-type limesdr --limesdr-lpfbw 2500000
$ ./dump1090 --device-type limesdr --limesdr-lpfbw 500000
Signed-off-by: Gluttton <gluttton@ukr.net>
Add ability to set the combined normalized gain via command line
options. By default the gain is equal to 0.75.
Test: connect LimeSDR device, try to set different gain and check logs:
$ ./dump1090 --device-type limesdr --limesdr-gain 0.01
$ ./dump1090 --device-type limesdr --limesdr-gain 0.5
$ ./dump1090 --device-type limesdr --limesdr-gain 0.99
Signed-off-by: Gluttton <gluttton@ukr.net>
Add ability to set RF oversampling ratio via command line options. By
default the default value is used.
Test: none.
Signed-off-by: Gluttton <gluttton@ukr.net>
Add ability to select a desired LimeSDR device by serial number. It is
not necessary to pass a whole serial number, but its key part is enough.
The first device which serial contains the passed key is selected.
Test: connect LimeSDR device and try to select it by serial number,
below an example for a device with serial 0009081C05C00000:
OK: $ ./dump1090 --device-type limesdr --limesdr-serial 9
OK: $ ./dump1090 --device-type limesdr --limesdr-serial 90
OK: $ ./dump1090 --device-type limesdr --limesdr-serial 908
NG: $ ./dump1090 --device-type limesdr --limesdr-serial 999
It hasn't been tested with several devices!
Signed-off-by: Gluttton <gluttton@ukr.net>
Add ability to set verbosity level for LimeSDR messages via command line
options. The range of available levels is from 0 to 4 and defined by the
constants from the `LimeSuite.h` file:
- LMS_LOG_CRITICAL 0;
- LMS_LOG_ERROR 1;
- LMS_LOG_WARNING 2;
- LMS_LOG_INFO 3;
- LMS_LOG_DEBUG 4.
By default the verbosity level is 3 (INFO).
Test: launch the program with different verbosity level and ensure that
number of messages is changed, for example:
$ ./dump1090 --device-type limesdr --limesdr-verbosity 4
$ ./dump1090 --device-type limesdr --limesdr-verbosity 3
$ ./dump1090 --device-type limesdr
Signed-off-by: Gluttton <gluttton@ukr.net>
The commit provides a basic implementation of support for LimeSDR USB
receivers based on LMS7002 chip. The solution has several limitations:
- passing parameters for tune LimeSDR receiver via command-line
options is not implemented;
- only hardcoded configuration is used (channel 0 of lower band LNA,
LMS_FMT_I16 format, gain, bandwidth and timeout);
- only one device is supported and it is not possible to select a
desired one in case if several devices are connected to the host.
Test: compare the output of the program for RTL and LimeSDR receivers.
Environment:
- RTL2832SDR dongle;
- LMS7002M based USB LimeSDR board;
- 800MHz-2200MHz omnidirectional antenna with SMA connector.
Procedure:
- connect RTL dongle to the host and start the program with the
following parameters:
$ ./dump1090 --device-type rtlsdr --interactive
- wait until several planes will be detected;
- stop the program, connect the LimeSDR board to the host and restart
the program with the following parameters:
$ ./dump1090 --device-type limesdr --interactive
- ensure that the same planes are detected.
Acceptance criteria: the same planes are detected using both receivers
and track information matches with information from the
FlightRadar24 application.
Signed-off-by: Gluttton <gluttton@ukr.net>
Oliver Jowett
Gluttton