How many {guidance system} are to/by {Global Positioning System} ?
What number of guidance systems are located at the Global Positioning System?
How many guidance systems are to be at Global Positioning System?
SELECT ( COUNT ( ?g ) AS ?p ) { ?g property:guidance_system resource:Global_Positioning_System }
SELECT (COUNT(?sub) AS ?subs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> ?sub .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P624> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q18822 .
} 

SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P624 wd:Q18822 }
6