My students were asked, in an exercise in their published workbook (in which there are sometimes mistakes), to identify the noun or nouns in a sentence within a passage about carrier pigeons being used for scientific research. The book said that "Each bird carried a GPS satellite tracking receiver on its back."(Punctuation as written: i.e. no commas.) The answer book identified 'GPS', 'satellite' and 'receiver' as separate nouns within the sentence.
I am confused. To me, 'GPS', 'satellite' and 'tracking' could be regarded as adjectives describing the only noun in the sentence, being 'receiver'. Either that or all four words could be forming a compound noun: the name of the object in question is a 'GPS satellite tracking receiver', rather like a 'bedside table' being one physical object but with two words to describe it.
I am sure that the answer book is wrong and that these are not separate nouns, but I am unclear whether there are three adjectives and a single word noun in this sentence, or whether there is a four-word compound noun and no adjectives.