Ackroyd, Neil. <br/><br/>
Global navigation :  a GPS user's guide / 
Neil Ackroyd and Robert Lorimer. 
 - 2nd ed. 
 - London :  Lloyd's of London Press,  1994. 
 - xxii, 196 p. :  ill., maps ;  24 cm.  
<br/><br/>Includes bibliography and index. 
<br/><br/><label>ISBN: </label>1850445176 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Global Positioning System.<br/>Artificial satellites in navigation.
<br/><br/><label>Dewey Class. No.: </label>629.045