carma::antenna::common::DriveControl Interface Reference

Drive system control interface More...

import "carma/antenna/common/DriveControl.idl";

Inheritance diagram for carma::antenna::common::DriveControl:

Classes
struct	RaDecEpoch
	Time-Tagged Ra/Dec value. More...

Public Types
enum	Aperture { OPTICAL, RADIO1MM, RADIO3MM, RADIO1CM }
	Enumerate apertures to use for selecting pointing models. More...
enum	AzWrapMode { ZERO, ADD, SUB }
	The azimuth drive can operate over more than a full circle, and the wrap logic dictates how the ambiguities are resolved when requesting RA/Dec positions. More...
enum	Position { ZENITH, SERVICE, SAFE }
	Enumerate valid fixed positions for Stow. More...
typedef sequence< RaDecEpoch, 3 >	RaDecTriplet

Public Member Functions
void	selectAperture (in DriveControl::Aperture ap) raises (carma::util::UserException)
void	setAntLocation (in double longitude, in double latitude, in double altitude) raises (carma::util::UserException)
	Specify the absolute antenna location Used in the computation of az and el for celestial sources. More...
void	setAperturePointingConstants (in DriveControl::Aperture ap, in float azOffset, in float elOffset, in float sag) raises (carma::util::UserException)
	Sets aperature pointing constants. More...
void	setAz (in double az, in unsigned long seq) raises (carma::util::UserException)
	Go to requested azimuth. More...
void	setAzel (in double az, in double el, in unsigned long seq) raises (carma::util::UserException)
	Go to requested az/el, setting the drive to horizon (azel) mode. More...
void	setAzMaxRate (in float azRate) raises (carma::util::UserException)
	Sets the maximum azimuth drive rate that can be requested. More...
void	setAzMountOffset (in double az, in unsigned long seq) raises (carma::util::UserException)
	Az mount offsets. More...
void	setAzOffset (in double az, in unsigned long seq) raises (carma::util::UserException)
	Az transient astronomical offsets. More...
void	setEl (in double el, in unsigned long seq) raises (carma::util::UserException)
	Go to requested elevation. More...
void	setElMaxRate (in float elRate) raises (carma::util::UserException)
	Sets the maximum elevation drive rate that can be requested. More...
void	setElMountOffset (in double el, in unsigned long seq) raises (carma::util::UserException)
	El mount offsets. More...
void	setElOffset (in double el, in unsigned long seq) raises (carma::util::UserException)
	El transient astronomical offsets. More...
void	setMaxRate (in float azRate, in float elRate) raises (carma::util::UserException)
	Sets the maximum drive rate that can be requested by the drive system software. More...
void	setMountOffset (in double az, in double el, in unsigned long seq) raises (carma::util::UserException)
	Az/El mount offsets. More...
void	setOffset (in double az, in double el, in unsigned long seq) raises (carma::util::UserException)
	Az/El transient astronomical offsets. More...
void	setSafeRange (in float azLow, in float azHigh, in float elLow, in float elHigh) raises (carma::util::UserException)
	Set the azimuth and elevation ranges within which this antenna is safe from collisions with other antennas. More...
void	setTiltmeterZero (in float aftForward, in float leftRight) raises (carma::util::UserException)
	Sets the zero point for the tiltmeter. More...
void	setTolerance (in float toleranceInArcsecs) raises (carma::util::UserException)
void	stop () raises (carma::util::UserException)
	Stop the antenna immediately. More...
void	stow (in DriveControl::Position pos, in unsigned long seq) raises ( carma::util::UserException )
	Go to a fixed position, such as vertical, safe or stow. More...
void	track (in string source, in RaDecTriplet positionTriplet, in DriveControl::AzWrapMode mode, in boolean overTheTop, in unsigned long seq) raises (carma::util::UserException)
	Set a new RA/Dec tracking position. More...
void	trackSnow () raises (carma::util::UserException)
	Starts tracking to minimize snow accumulation on dish surface. More...
void	trackWind () raises (carma::util::UserException)
	Starts tracking to minimize impact of heavy wind. More...
void	updateRaDec (in RaDecEpoch position, in DriveControl::AzWrapMode mode) raises ( carma::util::UserException )
	Update tracking with a new time-tagged Ra/Dec position. More...
void	updateWeather (in float ambientTemp, in float barometricPressure, in float relativeHumidity, in float dewpointTemp, in float windSpeed, in float windDirection) raises (carma::util::UserException)
	Update weather parameters. More...

Detailed Description

Drive system control interface

Quadratic interpolation is always used for equatorial coordinates, and may optionally be used for horizon coordinates. If the coefficients are updated every 800 seconds, the fastest comet, (Hyakutake), will have a position error of one arcsecond. The equatorial positions that are sent have a time tag and should be full apparent topocentric positions for the current location of the antenna, including equatorial offsets, ephemeris and proper motion, parallax, precession, nutation, polar motion, and diurnal and annual aberration. Only refraction is excluded. Horizon coordinate (azimuth and elevation) positions may also be used to point at terrestrial objects, like a pointing fiducial or transmitter. These positions will include any parallax. In all drive modes, the pointing model, aperture constants, and mount offsets are used as corrections to the encoder readings to get the actual position while the ra/dec and azel offsets are added to the requested position. The signs are such that a positive offset or model coefficient will increase the encoder reading for the affected axis.

All offsets take effect immediately, unless the drive is stopped or stowed, in which case they are just stored.

In the horizon coordinate system, azimuth is defined with zero to the north, increasing toward the east.

The drive system has an underlying construct of "drive mode" that is automatically changed by many of these commands. The drive modes are defined in the monitor system, and correspond to:

• equatorial (ra/dec)
• horizon (az/el)
• snowTrack
• stop
• stow

Many commands set a sequence number monitor point upon completion. These commands must also set an associated "driveSeqNumSuccess" boolean monitor point to indicate whether the command completed because of success (acquiring the position) or failure (the drive is disabled, local, etc).

Definition at line 80 of file DriveControl.idl.

Member Enumeration Documentation

enum carma::antenna::common::DriveControl::Aperture

Enumerate apertures to use for selecting pointing models.

Enumerator
OPTICAL	Optical telescopes.
RADIO1MM	Radio 1 mm.
RADIO3MM	Radio 3 mm.
RADIO1CM	Radio 1 cm.

Definition at line 85 of file DriveControl.idl.

enum carma::antenna::common::DriveControl::AzWrapMode

The azimuth drive can operate over more than a full circle, and the wrap logic dictates how the ambiguities are resolved when requesting RA/Dec positions.

The steps for converting an RA/Dec into an azimuth are:

• Convert to az in range [0-360] degrees.
• If az is outside the physical drive range, add or subtract a turn to put it within range.
• Check the AzWrapMode and add or subtract a turn as requested, but only if the result is within the physical range of the drive system.

Enumerator
ZERO	Don't add or subtract anything to the azimuth.
ADD	Add a turn to azimuth if result is inside physical range.
SUB	Subtract turn from az if result is inside physical range.

Definition at line 118 of file DriveControl.idl.

enum carma::antenna::common::DriveControl::Position

Enumerate valid fixed positions for Stow.

Enumerator
ZENITH	Pointed toward zenith.
SERVICE	A predefined service position.
SAFE	A collision-free position - currently implemented as the safe range midpoint. See Also DriveControl::setSafeRange

Definition at line 95 of file DriveControl.idl.

Member Function Documentation

void carma::antenna::common::DriveControl::setAntLocation	(	in double	longitude,
		in double	latitude,
		in double	altitude
	)
raises	(	carma::util::UserException
	)

Specify the absolute antenna location Used in the computation of az and el for celestial sources.

Parameters

longitude	East longitude in radians, 0 to 2pi (increasing from Greenwich toward the east)
latitude	in radians, -pi to pi
altitude	in meters above sea level

void carma::antenna::common::DriveControl::setAperturePointingConstants	(	in DriveControl::Aperture	ap,
		in float	azOffset,
		in float	elOffset,
		in float	sag
	)
raises	(	carma::util::UserException
	)

Sets aperature pointing constants.

An aperture is a radio receiver beam or optical telescope. These constants represent a collimation error and a sag and their effect has the same sign as setOffset(). In general all apertures offsets are relative to the mount model, with the exception of the 1mm aperture for the 6m & 10m antennas which are relative to the 3mm aperture because they are in a common dewar.

Parameters

aperture
azOffset	in arcmin, on the sky (collimation)
elOffset	in arcmin
sag	in arcmin. Elevation correction = sag*cosEl

void carma::antenna::common::DriveControl::setAz	(	in double	az,
		in unsigned long	seq
	)
raises	(	carma::util::UserException
	)

Go to requested azimuth.

Convenience method for direct control.

Parameters

az	azimuth in degrees
seq	Sequence number inserted into monitor system upon completion Also sets antennaCommon.driveSeqNumSuccess as true/false

See Also

setAzel

void carma::antenna::common::DriveControl::setAzel	(	in double	az,
		in double	el,
		in unsigned long	seq
	)
raises	(	carma::util::UserException
	)

Go to requested az/el, setting the drive to horizon (azel) mode.

If the drive is in equatorial mode or stopped and a single axis is selected (

See Also

setAz, setEl), then the current actual position of the non-selected axis is taken as the position to track for that axis. Azimuth is defined with zero as north, increasing to the east. Parallax for terrestrial sources (beacons or fiducials) should be included in the coordinates.

Parameters

az	azimuth in degrees
el	elevation in degrees
seq	Sequence number inserted into monitor system upon completion Also sets antennaCommon.driveSeqNumSuccess as true/false

void carma::antenna::common::DriveControl::setAzMaxRate	(	in float	azRate	)
raises	(	carma::util::UserException
	)

Sets the maximum azimuth drive rate that can be requested.

Parameters

azRate

max rate in azimuth (degrees/sec). This is an "on the sky" rate, not on the encoder

See Also

setAzMaxRate

void carma::antenna::common::DriveControl::setAzMountOffset	(	in double	az,
		in unsigned long	seq
	)
raises	(	carma::util::UserException
	)

Az mount offsets.

Parameters

az	azimuth offset on the sky (not encoder) (arcmin)

See Also

setMountOffset

void carma::antenna::common::DriveControl::setAzOffset	(	in double	az,
		in unsigned long	seq
	)
raises	(	carma::util::UserException
	)

Az transient astronomical offsets.

Previous elevation offset is reused.

Parameters

az	azimuth offset on the sky (not encoder) (arcmin)

See Also

setOffset

void carma::antenna::common::DriveControl::setEl	(	in double	el,
		in unsigned long	seq
	)
raises	(	carma::util::UserException
	)

Go to requested elevation.

Convenience method for direct control.

Parameters

el	elevation in degrees
seq	Sequence number inserted into monitor system upon completion Also sets antennaCommon.driveSeqNumSuccess as true/false

See Also

setAzel

void carma::antenna::common::DriveControl::setElMaxRate	(	in float	elRate	)
raises	(	carma::util::UserException
	)

Sets the maximum elevation drive rate that can be requested.

Parameters

elRate

max rate in elevation (degrees/sec)

See Also

setMaxRate

void carma::antenna::common::DriveControl::setElMountOffset	(	in double	el,
		in unsigned long	seq
	)
raises	(	carma::util::UserException
	)

El mount offsets.

Parameters

el	elevation offset (arcmin)

See Also

setMountOffset

void carma::antenna::common::DriveControl::setElOffset	(	in double	el,
		in unsigned long	seq
	)
raises	(	carma::util::UserException
	)

El transient astronomical offsets.

Previous azimuth offset is reused.

Parameters

el	elevation offset (arcmin)

See Also

setOffset

void carma::antenna::common::DriveControl::setMaxRate	(	in float	azRate,
		in float	elRate
	)
raises	(	carma::util::UserException
	)

Sets the maximum drive rate that can be requested by the drive system software.

A temporary rate less than the full slew rate that is used to keep collidable antennas from moving too rapidly.

Parameters

azRate	max rate in azimuth (degrees/sec). This is an "on the sky" rate, not on the encoder
elRate	max rate in elevation (degrees/sec)

See Also

setAzMaxRate, setElMaxRate

void carma::antenna::common::DriveControl::setMountOffset	(	in double	az,
		in double	el,
		in unsigned long	seq
	)
raises	(	carma::util::UserException
	)

Az/El mount offsets.

Slowly varying optics offsets with respect to the mount (collimation). These are set as the result of a pointing peak-up, etc. and may change on the time-scale of hours. These are redundant with some terms of the pointing model, but are exposed to conveniently track the delta's of these terms. These offsets are used in both equatorial and horizon modes. Behaves with the same sign as the setOffset() command.

Parameters

az	azimuth offset on the sky (not encoder) (arcmin)
el	elevation offset (arcmin)

See Also

setAzMountOffset, setElMountOffset

void carma::antenna::common::DriveControl::setOffset	(	in double	az,
		in double	el,
		in unsigned long	seq
	)
raises	(	carma::util::UserException
	)

Az/El transient astronomical offsets.

Horizon offsets used for engineering or astronomy. These offsets are used in both equatorial and horizon modes, and are set to zero when a new source is selected with track(). The offset is added to the az/el from the setAzel() command or derived from the track() command.

Parameters

az	azimuth offset on the sky (not encoder) (arcmin), interpreted as a collimation error
el	elevation offset (arcmin)

See Also

setAzOffset, setElOffset, track

void carma::antenna::common::DriveControl::setSafeRange	(	in float	azLow,
		in float	azHigh,
		in float	elLow,
		in float	elHigh
	)
raises	(	carma::util::UserException
	)

Set the azimuth and elevation ranges within which this antenna is safe from collisions with other antennas.

Note: an invocation stow(SAFE) must throw an exception if valid safe ranges have not been set with this command beforehand.

Parameters

azLow	- the low end of the safe azimuth range, in degrees.
azHigh	- the high end of the safe azimuth range, in degrees.
elLow	- the low end of the safe elevation range, in degrees.
elHigh	- the high end of the safe elevation range, in degrees.

See Also

DriveControl::stow()

void carma::antenna::common::DriveControl::setTiltmeterZero	(	in float	aftForward,
		in float	leftRight
	)
raises	(	carma::util::UserException
	)

Sets the zero point for the tiltmeter.

Parameters

aftForward	aft/forward zero in arcmin
leftRight	left/right zero in arcmin

void carma::antenna::common::DriveControl::stop	(		)
raises	(	carma::util::UserException
	)

Stop the antenna immediately.

On the OVRO antennas, this means de-energizing the drive controllers and applying the brakes. For BIMA, this means not applying any stepper motor drive pulses.

Todo:

what does this mean for SZA antennas?

void carma::antenna::common::DriveControl::stow	(	in DriveControl::Position	pos,
		in unsigned long	seq
	)
raises	(	carma::util::UserException
	)

Go to a fixed position, such as vertical, safe or stow.

After the stow position is achieved, disable the drive system. The drive system will automatically be re-energized when any command is given to go to a new position. For an OVRO antenna, disabling the drives means turning off the controllers and applying the brakes. For a BIMA antenna it means not emitting stepper motor pulses.

Parameters

position	The requested fixed position
seq	Sequence number inserted into monitor system upon completion Also sets antennaCommon.driveSeqNumSuccess as true/false

See Also

Position

DriveControl::setSafeRange()

void carma::antenna::common::DriveControl::track	(	in string	source,
		in RaDecTriplet	positionTriplet,
		in DriveControl::AzWrapMode	mode,
		in boolean	overTheTop,
		in unsigned long	seq
	)
raises	(	carma::util::UserException
	)

Set a new RA/Dec tracking position.

An array of three time-tagged equatorial positions are stored and used as the basis for quadratic interpolation to obtain the current position.

Use the updateRaDec method to update RA/Dec values.

Positions are FK5 for the current epoch, with any proper motion applied. Precession, nutation, polar motion, aberration, parallax, and any equatorial offsets have also been applied. Refraction has not been applied. Automatically changes tracking mode to equatorial (ra/dec). The offsets set with setOffset are reset to zero. If the requested position is beyond the software limits then the antenna goes to the software limits and the appropriate designation is set in the monitor stream.

Parameters

source	Source name for information purposes only.
positionTriplet	Sequence of three TimeTaggedRaDec values.
azWrapMode	azWrapMode, see AzWrapMode
overTheTop	whether to use an elevation greater than 90 degrees. This parameter is currently ignored and is included as a placeholder in case it is needed in the future.
seq	Sequence number inserted into monitor system upon completion Also sets antennaCommon.driveSeqNumSuccess as true/false

See Also

updateRaDec, offset

void carma::antenna::common::DriveControl::trackSnow	(		)
raises	(	carma::util::UserException
	)

Starts tracking to minimize snow accumulation on dish surface.

Implementation uses wind direction sent with the weather commands. For ovro antennas tracking is done into the wind at a 60 degree offset from the wind vector. Bima antennas track with their backs to the wind (opposite the wind vector).

void carma::antenna::common::DriveControl::trackWind	(		)
raises	(	carma::util::UserException
	)

Starts tracking to minimize impact of heavy wind.

Ovro antennas are stowed during a wind track and bima dishes track with their backs to the wind (opposite the wind vector).

void carma::antenna::common::DriveControl::updateRaDec	(	in RaDecEpoch	position,
		in DriveControl::AzWrapMode	mode
	)
raises	(	carma::util::UserException
	)

Update tracking with a new time-tagged Ra/Dec position.

When a new update is received it replaces the oldest of the triplet values stored in memory. This routine is for updates only, use track to start tracking a new source or position.

Parameters

TimeTaggedRaDec

New RA/Dec value and corresponding timestamp.

See Also

track

track

void carma::antenna::common::DriveControl::updateWeather	(	in float	ambientTemp,
		in float	barometricPressure,
		in float	relativeHumidity,
		in float	dewpointTemp,
		in float	windSpeed,
		in float	windDirection
	)
raises	(	carma::util::UserException
	)

Update weather parameters.

Used to compute refraction correction The dewpoint/relative humidity is redundant, but allows the antennas to use whichever they want.

Parameters

ambientTemp	ambient temperature in Celsius (air temp at the antenna or weather station)
barometricPressure	in millibars
relativeHumidity	in percent (a number between 0 and 100)
dewpointTemp	in Celsius
windSpeed	in miles/hour
windDirection	direction wind is coming from, in degrees, with north at 0, increasing to the east. This is not the direction that the wind vector points, but the direction that a vane would point and is the common weather definition

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The documentation for this interface was generated from the following file:

• carma/antenna/common/DriveControl.idl