Structures

This section contains a description of the custom signal structures shared by Skydel.

Skydel provides custom signal plug-ins with various information across different simulation states. This information is always passed using a map based structure to allow for future flexibility and extensibility.

This page details all data structures related to custom signals by listing the available keys. Each key is accompanied by a definition to give context about the associated information, along with its corresponding C++ type.

Here is an example of how to access the eccentricity value from the ConstellationParameters structure:

//            value                 type                     key
//              |                    |                        |
const auto eccentricity = std::get<double>(parameters.at(ECCENTRICITY_KEY));

InitializationDatas

The InitializationDatas structure contains information about both the custom signal and the simulation that is about to start. It is passed to custom signal plug-ins during the createCustomSignal call.

Key Name	Definition	Format	Type
startWeek	Week of the simulation start time	-	uint32_t
startSecondOfWeek	Second number of the simulation start time week	seconds	uint32_t
pathToXml	XML configuration file path	-	std::string
xmlFileName	XML configuration file name	-	std::string
customSignalName	Custom signal name	-	std::string
alpha0	Ionospheric coefficent Alpha 0	seconds	double
alpha1	Ionospheric coefficent Alpha 1	seconds / semicircle	double
alpha2	Ionospheric coefficent Alpha 2	seconds / semicircle²	double
alpha3	Ionospheric coefficent Alpha 3	seconds / semicircle³	double
beta0	Ionospheric coefficent beta 0	seconds	double
beta1	Ionospheric coefficent Beta 1	seconds / semicircle	double
beta2	Ionospheric coefficent Beta 2	seconds / semicircle²	double
beta3	Ionospheric coefficent Beta 3	seconds / semicircle³	double
tot	Time data reference TOW	-	uint32_t
wnot	Time data reference week number	-	uint32_t
a0	Bias coefficient of GPS to UTC	-	double
a1	Drift coefficient of GPS to UTC	-	double
a2	Drift rate coefficient of GPS to UTC	-	double
deltaTLS	Leap second count	-	int32_t
wnLSF	Week number of future leap second	-	uint32_t
dn	Day of future leap second	-	uint32_t
deltaTLSF	Current or future leap second count	-	int32_t

ConstellationDatas

The ConstellationDatas structure contains information about the constellation associated with the custom signal. The key in the map corresponds to the dataset type associated with each ConstellationData.

Here are the available dataset keys:

Key Name	Definition
EPHEMERIS	Ephemeris data set type.

At the current time, only the EPHEMERIS dataset type is shared to custom signals.

ConstellationParameters

The ConstellationParameters structure contains information about specific parameters related to the custom signal's constellation. It is represented as a map, where the keys are the names of the parameters, each pointing to a ConstellationParameter. Each ConstellationParameter is a variant that can take the form of a uint32_t, int32_t, double, or bool, depending on the parameter.

Each constellation has its own specific set of parameters, which are described in the following sections.

Kepler

The following parameters are shared when the custom signal constellation is Keplerian, that is, for any constellation except Glonass and SBAS.

Key Name	Definition	Format	Type
prn	Satellite PRN	-	uint32_t
iod	Issue of data	-	uint32_t
wnop	Week number of prediction	-	uint32_t
top	Time of prediction	seconds	uint32_t
wnoc	Week number of clock	-	uint32_t
toc	Time of clock	seconds	uint32_t
af0	SV clock bias	seconds	double
af1	SV clock drift	seconds / second	double
af2	SV clock bias	seconds / second²	double
wnoe	Week number of ephemeris	-	uint32_t
toe	Time of ephemeris	seconds	uint32_t
sqrtA	Square root semi major axis	meters½	double
eccentricity	Eccentricity	-	double
inclination	Inclination angle	semicircles	double
lonAscendNode	Longitude of ascending node	semicircles	double
rateOfRightAscen	Rate of right ascension	semicircles / second²	double
meanAnomaly	mean anomaly	semicircles	double
argumentOfPerigee	Argument of perigee	-	double
meanMotionDiff	Mean motion difference	semicircles / second	double
iDot	rate of inclination angle	semicircles / second	double
crs	Correction radius sine	meters	double
crc	Correction radius cosine	meters	double
cuc	Correction argument lat sine	radians	double
cus	Correction argument lat sine	radians	double
cic	Correction inclination sine	radians	double
cis	Correction inclination sine	radians	double

GPS

The following parameters are shared when the custom signal constellation is GPS, supplementing the Kepler parameters.

Key Name	Definition	Format	Type
gpsTgd	Time group delay	seconds	double
iodc	Issue of data clock	-	uint32_t
codesOnL2	Codes on L2	-	uint32_t
l2PDataFlag	L2P data flag	-	uint32_t
svSignalHealth	SV signal health	5 bits	uint32_t
svDataHealth	SV data health	3 bits	uint32_t
fitInterval	Fit interval	seconds	uint32_t
uraIndex	URA index	-	uint32_t
integrityStatusFlag	Integrity status flag	-	uint32_t
l2CPhasing	L2C phasing	-	uint32_t
uraEdIndex	URA ED index	-	int32_t
uraNed0Index	URA NED 0 index	-	int32_t
uraNed1Index	URA NED 1 index	-	int32_t
uraNed2Index	URA NED 2 index	-	int32_t
iscL1CaAvailable	Is L1CA inter symbol correction enabled	-	bool
iscL2CAvailable	Is L2C inter symbol correction enabled	-	bool
iscL5I5Available	Is L5I5 inter symbol correction enabled	-	bool
iscL5Q5Available	Is L5Q5 inter symbol correction enabled	-	bool
iscL1CPAvailable	Is L1CP inter symbol correction enabled	-	bool
iscL1CDAvailable	Is L1CD inter symbol correction enabled	-	bool
iscL1Ca	L1CA inter symbol correction	seconds	double
iscL2C	L2C inter symbol correction	seconds	double
iscL5I5	L5I5 inter symbol correction	seconds	double
iscL5Q5	L5Q5 inter symbol correction	seconds	double
iscL1CP	L1CP inter symbol correction	seconds	double
iscL1CD	L1CD inter symbol correction	sedoncs	double
signalHealth	L1/L2 signal health of LNAV	5 bits	uint32_t
dataHealth	L1/L2 data health of LNAV	3 bits	uint32_t
svConfig	SV configuration	3 bits	int32_t
l1Health	L1 health of CNAV and CNAV2	-	bool
l2Health	L2 health of CNAV and CNAV2	-	bool
l5Health	L5 health of CNAV and CNAV2	-	bool
l1cHealth	L1C health of CNAV2	-	bool
navAlertFlag	NAV alert flag	-	bool
cNavAlertFlag	CNAV alert flag	-	bool

Galileo

The following parameters are shared when the custom signal constellation is Galileo, supplementing the Kepler parameters.

Key Name	Definition	Format	Type
galileoBgdE5a	Group delay of E5a	seconds	double
galileoBgdE5b	Group delay of E5b	seconds	double
sisaE5a	SISA E5a	8 bits	uint32_t
sisaE5b	SISA E5b	8 bits	uint32_t
signalHealthE5a	Signal health of E5a	2 bits	uint32_t
signalHealthE5b	Signal health of E5b	2 bits	uint32_t
signalHealthE1B	Signal health of E1B	2 bits	uint32_t
dataHealthE5a	Data validity of E5a	-	bool
dataHealthE5b	Data validity of E5b	-	bool
dataHealthE1B	Data validity of E1B	-	bool

BeiDou

The following parameters are shared when the custom signal constellation is BeiDou, supplementing the Kepler parameters.

Key	Definition	Format	Type
beiDouTgd1	Time group Delay 1	seconds	double
beiDouTgd2	Time group delay 2	seconds	double
beiDouTgdb1cp	Time group delay of B1C pilot component	seconds	double
beiDouTgdb2ap	Time group delay of B2A pilot component	seconds	double
aodc	Age of data clock	-	uint32_t
aode	Age of data ephemeris	-	uint32_t
iodc	Issue of data clock	-	uint32_t
satH2	Satellite health flag for integrity and differential correction information	2 bits	uint32_t
iscB1CdAvailable	Is B1C inter symbol correction enabled	-	bool
iscB1Cd	B1C inter symbol correction	seconds	double
uraIndex	URA index	-	uint32_t
healthInfo	Nav satellite health information	9 bits	uint32_t
autonomousHealth	Autonomous satellite health	-	bool
cnavHealthInfo	CNav satellite health information	8 bits	uint32_t
healthStatus	Satellite health status	2 bits	uint32_t

Glonass

The following parameters are shared when the custom signal constellation is Glonass.

Key Name	Definition	Unit	Type
t_lambda	Reference time of almanac	seconds	double
tau_c	Correction from GLONASS to UTC	seconds	double
tau_gps	Correction to GPS time relative to GLONASS	seconds	double
tau_n	Correction of satellite time relative to GLONASS	seconds	double
lambda	Longitude of first ascending node passage	semicircles	double
delta_i	Correction to the mean value of inclination	semicircles	double
omega	Argument of perigee	semicircles	double
e	Eccentricity	-	double
delta_t	Correction of the mean value of Draconian period	seconds	double
delta_t_rate	Rate of change of Draconian period	seconds / coil	double
tauN	Correction of time relative to GLONASS	seconds	double
svRelativeFrequencyBias	SV relative frequency bias	hz	double
messageFrameTime	Mesage frame time	seconds	uint32_t
age	Age of oper. information	days	uint32_t
positionX	X position	kilometers	double
positionY	Y position	kilometers	double
positionZ	Z position	kilometers	double
velocityX	X velocity	kilometers / second	double
velocityY	Y velocity	kilometers / second	double
velocityZ	Z velocity	kilometers / second	double
accelerationX	X acceleration	kilometers / second²	double
accelerationY	Y acceleration	kilometers / second²	double
accelerationZ	Z acceleration	kilometers / second²	double