( ( Global ( Positioning System ) ) ( ( -LRB- ( GPS -RRB- ) ) ( ( ( Global ( Positioning Systems ) ) ( -LRB- ( GPS -RRB- ) ) ) ( ( ( are worldwide ) ( ( radio-navigation systems ) ( formed ( from ( ( a constellation ) ( of ( ( ( 24 satellites ) and ) ( their ( ground stations ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (NP (NNP Global) (NNP Positioning) (NNP System)) (PRN (-LRB- -LRB-) (NP (NNP GPS)) (-RRB- -RRB-)) (NP (NP (NNP Global) (NNP Positioning) (NNPS Systems)) (PRN (-LRB- -LRB-) (NP (NNP GPS)) (-RRB- -RRB-))) (VP (VBP are) (ADVP (RB worldwide)) (NP (NP (JJ radio-navigation) (NNS systems)) (VP (VBN formed) (PP (IN from) (NP (NP (DT a) (NN constellation)) (PP (IN of) (NP (NP (CD 24) (NNS satellites)) (CC and) (NP (PRP$ their) (NN ground) (NNS stations))))))))) (. .)))
Global Positioning System (GPS) Global Positioning Systems (GPS) are worldwide radio-navigation systems formed from a constellation of 24 satellites and their ground stations.
(ROOT (S (S (NP (PRP We)) (VP (VBP call) (NP (NP (DT the) (JJ worldwide) (JJ radio-navigation) (NN system)) (VP (VBN formed) (PP (IN from) (NP (NP (DT a) (NN constellation)) (PP (IN of) (NP (CD 24) (NNS satellites))))))))) (CC and) (S (NP (PRP$ their) (NN ground) (NNS stations)) (VP (VBP gps))) (. .)))