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measures.asbaseline - Function

1.4.1 define a baseline from a position measure


Description

asbaseline converts a position measure into a baseline measure. No actual baseline is calculated, since operations can be done on positions, with subtractions to obtain baselines at a later stage.

Arguments





Inputs

pos

position measure

allowed:

record

Default:

Returns
record

Example

 
 
print "\t----\t asbaseline Ex 1 \t----"  
 
####An example of getting baselines with 3 antenna positions  
#### Define the frame ; where, which-direction and when  
me.doframe(me.observatory(’VLA’))  
me.doframe(me.direction(’J2000’, ’19h20m00’, ’20d10m00’))  
me.doframe(me.epoch(’utc’, ’2007/07/08/20:30:00’))  
 
##antenna position  
ants=me.position(’itrf’,qa.quantity([3828763.11,3828746.55, 3828727.43],’m’), qa.quantity([442449.106,442592.14, 442580.12],’m’), qa.quantity([5064923.01, 5064923.01, 5064923.51],’m’))  
print ants  
#{’type’: ’position’, ’refer’: ’ITRF’, ’m1’: {’value’: array([ 0.92031276,  0.92031276,  0.92031535]), ’unit’: ’rad’},  
#’m0’: {’value’: array([ 0.11504897,  0.11508633,  0.1150838 ]), ’unit’: ’rad’},  
#’m2’: {’value’: array([ 6364639.28758924,  6364639.27051283,  6364627.33064587]), ’unit’: ’m’}}  
 
bl=me.asbaseline(ants)  
print bl  
#{’type’: ’baseline’, ’refer’: ’J2000’, ’m1’: {’value’: array([ 0.92068328,  0.92068326,  0.92068585]), ’unit’: ’rad’},  
#’m0’: {’value’: array([-2.08658811, -2.08655073, -2.08655326]), ’unit’: ’rad’},  
#’m2’: {’value’: array([ 6364639.28758924,  6364639.27051283,  6364627.33064587]), ’unit’: ’m’}}  
 
me.expand(bl)  
 
#{’return’: {’m0’: {’unit’: ’rad’,  
#                  ’value’: array([-0.51637894, -0.36575235,  1.50036599])},  
#            ’m1’: {’unit’: ’rad’,  
#                   ’value’: array([-0.00060966,  0.00302388,  0.02206414])},  
#            ’m2’: {’unit’: ’m’,  
#                   ’value’: array([ 143.98943974,  135.78652583,   22.58992696])},  
#            ’refer’: ’J2000’,  
#            ’type’: ’baseline’},  
# ’xyz’: {’unit’: ’m’,  
#         ’value’: array([  1.25215025e+02,  -7.10925354e+01,  -8.77850493e-02,  
#         1.26804339e+02,  -4.85640980e+01,   4.10601842e-01,  
#         1.58931410e+00,   2.25284374e+01,   4.98386892e-01])}}  
 
 
 

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