SatYAML files are used by gr-satellites to describe the properties of each
specific satellite, such as what kind of protocols and telemetry formats it
uses. They are YAML files and are based around the concept of
components. Using SatYAML files, the
gr_satellites command line tool and the
Satellite decoder block can figure out which components to put together to
decode a particular satellite.
SatYAML files are stored in the
python/satyaml directory. Below we show the
1KUNS-PF.yml to give an overall idea of the format of these
&image JPEG Images:
1k2 FSK downlink:
framing: AX100 ASM+Golay
9k6 FSK downlink:
framing: AX100 ASM+Golay
First we can see some fields that give basic information about the
name field indicates the main name of the satellite, which is
gr_satellites and the Satellite decoder block when calling up the
satellite by name. There is an optional list of
alternative_names which can
also be used to call up the satellite by name. The
norad field gives the
NORAD ID of the satellite and it is used when calling up the satellite by
Additional telemetry servers used for this satellite can be specified with the
telemetry_servers field (see
python/satyaml/PW-Sat2.yml for an example).
data section indicates the different kinds of data transmissions that
the satellite makes, and gives the decoders for them. The following can be used:
telemetry, which specifies a telemetry decoder giving out the telemetry definition (see Telemetry parser)
image, which specify a file receiver or image receiver giving out the
ImageReceiverclass (see File and Image receivers)
decoder, which specifies a custom decoder from
satellites.components.datasinks. This is used for more complex decoders not covered by the above.
unknown, which specifies that the data format is not known, so hex dump should be used to show the data to the user
transmitters section lists the different transmitters used by the
satellite, their properties, and ties them to the entries in the
data section according as to which data is sent by each of the transmitters.
A transmitter is understood as a specific combination of a frequency,
modulation and coding.
Each transmitter has a name (such as
1k2 FSK downlink) which is currently
used only for documentation purposes, a
frequency, which gives the downlink
frequency in Hz (currently used only for documentation), a
specifies the demodulator component to use, a
baudrate, in symbols per
framing, that specifies the deframer to use, and a list of
data that has entries referring to the items in the
The modulations allowed in the
modulation field are the following:
AFSK, for which the AFSK demodulator is used
FSK, for which the FSK demodulator with Subaudio set to
FSK subaudio, for which the FSK demodulator with Subaudio set to
BPSK. Coherent BPSK, for which the BPSK demodulator with Differential and Manchester set to
BPSK Manchester. Coherent Manchester-encoded BPSK, for which the BPSK demodulator with Differential set to
Falseand Manchester set to
DBPSK. Differentially-encoded BPSK, for which the BPSK demodulator with Differential set to
Trueand Manchester set to
Falseis used to perform non-coherent demodulation
DBPSK Manchester. Differentially-encoded and Manchester-encoded BPSK, for which the BPSK demodulator with Differential and Manchester set to
Trueis used to perform non-coherent demodulation
AFSK modulation also needs the
that indicate the AFSK tone frequencies in Hz, as in the AFSK demodulator.
The framings allowed in the
framing field are the following:
AX.25, AX.25 with no scrambling (see AX.25 deframer)
AX.25 G3RUH, AX.25 with G3RUH scrambling (see AX.25 deframer)
AX100 ASM+Golay, GOMspace NanoCom AX100 in ASM+Golay mode (see GOMspace AX100 deframer)
AX100 Reed Solomon, GOMspace NanoCom AX100 in Reed-Solomon mode (see GOMspace AX100 deframer)
U482C, the GOMspace NanoCom U482C (see GOMspace U482C deframer)
AO-40 FEC, the AO-40 FEC protocol (see AO-40 FEC deframer)
AO-40 FEC short, AO-40 FEC protocol with short frames, as used by SMOG-P and ATL-1
AO-40 FEC CRC-16-ARC, the AO-40 FEC protocol with an CRC-16 ARC, as used by SMOG-1
AO-40 FEC CRC-16-ARC short, AO-40 FEC protocol with short frames and a CRC-16 ARC, as used by SMOG-1
CCSDS Uncoded, uncoded CCSDS codeworks (see CCSDS deframers)
CCSDS Reed-Solomon, CCSDS Reed-Solomon TM codewords (see CCSDS deframers)
CCSDS Concatenated, CCSDS Concatenated TM codewords (see CCSDS deframers)
3CAT-1, custom framing used by 3CAT-1. This uses a CC1101 chip with PN9 scrambler and a (255,223) Reed-Solomon code for the payload
Astrocast FX.25 NRZ-I, custom framing used by Astrocast 0.1. This is a somewhat non compliant FX.25 variant.
Astrocast FX.25 NRZ, custom framing used by Astrocast 0.1. This is a somewhat non compliant FX.25 variant that is identical to the FX.25 NRZ-I mode except that NRZ is used instead of NRZ-I.
AO-40 uncoded, uncoded AO-40 beacon. It uses 512 byte frames and a CRC-16
TT-64, custom framing used by QB50 AT03, which uses a Reed-Solomon (64,48) code and CRC16-ARC
ESEO, custom framing used by ESEO. It uses a custom protocol vaguely similar to AX.25 with some form of G3RUH scrambling and a (255,239) Reed-Solomon code
Lucky-7, custom framing used by Lucky-7, which uses a SiLabs Si4463 transceiver with a PN9 scrambler and a CRC-16
Reaktor Hello World, custom framing used by Reaktor Hello World. It uses a Texas Intruments CC1125 transceiver with a PN9 scrambler and a CRC-16
S-NET, custom framing used by S-NET, which uses BCH FEC and interleaving
SALSAT, custom framing used by SALSAT. It is like
S-NET, but without the bugs in the CRC implementation.
Swiatowid, custom framing used by Swiatowid for image transmission, which includes a (58,48) Reed-Solomon code and a CRC-16CCITT.
NuSat, custom framing used by ÑuSat with a (64, 60) Reed-Solomon code and a CRC-8
K2SAT, custom framing used by K2SAT for image transmission. This uses the CCSDS r=1/2, k=7 convolutional code and the IESS-308 (V.35) asynchronous scrambler.
LilacSat-1, low latency decoder for LilacSat-1 codec2 digital voice and image data. This uses the CCSDS r=1/2, k=7 convolutional code and interleaved telemetry and Codec2 digital voice
AAUSAT-4, custom framing used by AAUSAT-4, which is similar to the CCSDS Concatenated coding
NGHam, NGHam protocol
NGHam no Reed Solomon, NGHam protocol without Reed-Solomon, as used by FloripaSat-1
SMOG-P RA, Repeat-Accumulate FEC as used by SMOG-P and ATL-1
SMOG-1 RA, Repeat-Accumulate FEC as used by SMOG-1. The difference with
SMOG-P RAis a longer 48 bit syncword (instead of 16 bit) and the inclusion of a CRC-16 ARC to check frame integrity.
SMOG-P Signalling, custom signalling frames as used by SMOG-P and ATL-1
SMOG-1 Signalling, custom signalling frames as used by SMOG-1. The difference with
SMOG-P Signallingis the addition of a different PRBS to mark transitions to TX mode.
OPS-SAT, custom framing used by OPS-SAT, which consists of AX.25 frames with CCSDS Reed-Solomon codewords as payload
UA01, non-AX.25 compliant framing used by QB50 UA01, which is like regular AX.25 but with two layers of NRZ-I encoding
Mobitex, the Mobitex protocol, used by the D-STAR ONE satellites and some Russian whose communications payload has also been built by German Orbital Systems
Mobitex-NX, the Mobitex-NX protocol, used by the BEESAT and TECHNOSAT satellites from TU Berlin
FOSSATSAT, a custom protocol used by FOSSASAT
AISTECHSAT-2, a custom CCSDS-like protocol used by AISTECHSAT-2
AALTO-1, custom framing used by AALTO-1. It uses a Texas Intruments CC1125 transceiver with a PN9 scrambler and a CRC-16 CCITT (as in AX.25)
Grizu-263A, custom framing used by Grizu-263A. It uses a Semtech SX1268 with a PN9 scrambler and CRC-16.
IDEASSat, custom framing used by IDEASSat. It uses NRZI encoding, an 1N8 UART-like encoding with MSB-bit-ordering, and HDLC
0x7eflags to mark the frame boundaries.
YUSAT, custom framing used by YUSAT-1. It is like AX.25 but without bit stuffing, LSB byte endianness, and NRZ-I.
AX5043, FEC framing used by the AX5043 transceiver IC. This uses a convolutional code, a 4x4 interleaver, and HDLC framing with the CRC16-USB.
USP, the Unified SPUTNIX Protocol, which is based on CCSDS concatenate frames with custom synchronization and a PLS based on DVB-S2.
DIY-1, the custom framing used by DIY-1, which uses an RFM22 chip transceiver.
BINAR-1, the custom framing used by the BINAR-1 satellite.
Endurosat, the custom framing used by the Endurosat modem.
Some framings, such as the CCSDS protocols need the additional field
frame size to indicate the frame size.
The CCSDS framings need several additional fields to specify the details of the CCSDS protocol. These are:
precoding: differentialshould be used to specify differential precoding. It if is not specified, differential precoding will not used.
RS basis:should have the value
dualto specify the Reed-Solomon basis. This field is mandatory.
RS interleaving:should be used to specify interleaved Reed-Solomon codewords. It defaults to 1 (i.e., no interleaving) if not specified.
scrambler:should have the value
none. This field is optional and defaults to
CCSDSif not specified.
convolutional:should have one of the following values:
NASA-DSN uninverted. This field is optional and defaults to
CCSDSif not specified.
AX100 ASM+Golay mode also supports the
scrambler field, with the
none. The default is
CCSDS, but the value
none can be used in case the scrambler needs to be disabled (which is a
rarely used feature).
The following example shows how transports are indicated in SatYAML files.
protocol: KISS KS-1Q
20k FSK downlink:
framing: CCSDS Concatenated dual
frame size: 223
Instead of specifying a
data entry in the transmitter, a
entry is used instead. Transports are defined in a section above. They have a
name, used for documentation purposes, a
protocol, and a list of
entries to tie them with the appropriate data decoders.
The allowable transport protocols are the following: