- CIRCUM
- position represent offsets from a geocentric spherical surface containing the reference position.
- TAN
- position represents offsets from a tangent plane at the reference position
- EQUITORIAL
- position represents linear offsets in the ITRF frame
- NTypes
- number of types
A heterogenous array (e.g. a VLBI array) can be described with multiple SimArray objects, usually held by a SimArrayList. This class handles the recording of information to an MS ANTENNA table. Obviously, when a SimArray is flushed to a Measurement Set, its data is written out in multiple rows, one for each antenna.
Positions can be given in one of several coordinate systems; see the description LocalCoord below for the definitions. Alternatively, this class can hold a single antenna position, given by a position measure; this is most convenient for defining a VLBI array of hetergenous antennas.
The positions, along with the rest of the antenna description data, are set at construction and cannot be changed later. The only writable data of this class are a row marker (via setRow(), used by SimArrayList) and an optional sub-array index. The sub-array index is assigned to the set of antennas as a whole; however, this is not recorded to the ANTENNA table.
CIRCUM the positions are offsets from a geocentric spherical surface
containing the reference position. x is a longitudinal offset
(i.e. not along a great circle) increasing to the east, y is
latitudinal offset increasing to the north, and z is the
altitude relative to the reference location.
TAN the positions are offsets from a tangent plane to a
geocentric spherical surface containing the reference
position. x is the offset increasing to the east, y is
the offset increasing to the north, and z is the
altitude (relative to the reference location).
EQUITORIAL the positions represent are offsets from the reference
position in the rectangular system defined by the ITRS
coordinate frame in which y is parallel to the north pole.
Thus, a simple vector addition of the offsets to the ITRS
vector of the reference position gives you the ITRS position
of the antenna.
Define a single antenna. This is useful for adding elements of a VLBI network of heterogenous dishes one at a time. name the name of the antenna or station pos defines the absolute position on the Earth of an antenna (the reference Location is not used). diam is the diameter of the dishes mount is the mount used on the antenna subarrayId is default subarray to associate these antennas with.
get and set the row ID, the row of the first antenna making up this array. An ID less than zero means that set has not yet been recorded. This is mainly used by SimArrayList to flush the SimArray data to a MeasurementSet's ANTENNA table.
get and set the default subarray ID
fill the antennas positions associated with this record into a given vector. start is the position in the vector to place the first antenna described by this record. The vector should already be of sufficient size (no size checking on pos nor bounds checking on start is done). The number of antennas loaded is returned.
fill the antenna positions as an array of ITRF position vectors. The first axis of the given Matrix represents the 3 components of the position vector in units of meters in the ITRF frame; the second axis is equal to the number of antennas in this subarray. start is the position along the second axis to place the first antenna described by this record. The matrix should already be of sufficient size (no size checking on pos nor bounds checking on start is done). The number of antennas loaded is returned.
fill the antenna names. If the names have not been set, the names will be returned as empty strings. start is the position in the vector to place the first name for this set of antennas. The vector should already be of sufficient size (no size checking on pos nor bounds checking on start is done). The number of antennas loaded is returned.
fill the station names. If the names have not been set, the names will be returned as empty strings. start is the position in the vector to place the first name for this set of antennas. The vector should already be of sufficient size (no size checking on pos nor bounds checking on start is done). The number of antennas loaded is returned.
An important function handled by this class is the recording of the antenna descriptions to a Measurement Set. This is done with the flush() function. When it writes the data from a SimArray in its list to the MS, it sets the row number (for the first antenna in the array) via setRow(); this is used as a flag indicating that the SimArray as been flushed. This allows one to later add additional SimArrays to the list; when flush is called again, only the new SimArray data are written out. This, of course, assumes that the same output MSAntenna is passed to the flush() function each time. If you want to write all the data to a new ANTENNA table, you can call clearIds() to clear all the row markers.
A set of antennas can be read in from an ANTENNA table as well using the initFrom() method or the SimArrayList(const MSAntenna&, ...) constructor. These will implicitly set the row markers from the input table. This allows one to add new antennas to the already recorded set.
load the antennas described in the given ANTENNA table
create a copy
reset all the row markers used to flag the SimArray members that have been recorded to a Measurement Set already. Thus, the next call to flush() will record all SimArrays to the ANTENNA table. This should be used when writing to a new ANTENNA table, different from one previously read from or written to.
remove all SimArray objects from this list.
access the i-th SimArray object in this list. Note that a SimArray object can describe several identical antennas.
access the SimArray object that describes the i-th antenna stored in this list.
return the number of antennas described in this list.
return the number of SimArray objects (each which may describe multiple identical antennas) in this list.
Define and add a set of antennas. The size of all input arrays must be equal to the number antennas being set. x,y,z define the position of the antennas relative to the reference location. unit is the unit of time or length used to give positions (if unit is time, values will be multiplied by the speed of light). This value should be a string recognized as a time or length by the MVTime and MVBaseline (via Quantity). coord is the coordinate system for the position vector x,y,z; the value is taken from the SimArray::LocalCoord enumeration. refloc is the reference location for the array. diam is the diameter of the dishes. mount is name of the mount employed by the antennas. antNames is a list of antenna names (e.g. "Ant 1"). stationNames is a list of station names (e.g. "N8"). offset is the offset from the "feed reference position" from the antenna positions, given as a pointer. (The offset position will be copied; thus, the caller is in charge of the memory.) subarrayID is default subarray to associate these antennas with.
Define and add a single antenna. This is useful for adding elements of a VLBI network of heterogenous dishes one at a time. name the name of the antenna or station pos defines the absolute position on the Earth of an antenna (the reference Location is not used). diam is the diameter of the dishes mount is the mount used on the antenna subarrayId is default subarray to associate these antennas with.
fill the currently configured antennas positions into a given vector. The vector will be resized appropriately. The number of antennas is returned.
fill the currently configured antenna positions as an array of ITRF position vectors. The first axis of the given Matrix represents the 3 components of the position vector in units of meters in the ITRF frame; the second axis is equal to the number of antennas in this subarray. start is the position along the second axis to place The matrix will be resized appropriately. The number of antennas is returned.
fill the antenna names into a given Vector of Strings. If the names have not been set, the names will be returned as empty strings. In any event, the given vector will be resized. The number of antennas is returned.
fill the station names into a given Vector of Strings. If the names have not been set, the names will be returned as empty strings. In any event, the given vector will be resized. The number of antennas is returned.
add array descriptions from an MS ANTENNA table
write out all antennas that have yet to be written to an MS ANTENNA table.