argued the State’s witness on GPS technology was not qualified under Rule 702. Id. The expert testified that: (1) he worked with GPS on a daily basis to prepare maps and pinpoint the location of residences for various purposes, including 911 operators; (2) that GPS works by bouncing signals from several satellites in order to triangulate the receiver’s location; (3) that GPS technology is accurate; and (4) that GPS is accepted as valid in many civilian, as well as military, applications requiring positioning data. Id. The witness’ expertise in GPS technology was established through his work experience and training and not through a formal background or education in the underlying scientific principles of GPS technology. Id. See also Alvarado v. State, 912 S.W.2d 199 (Tex.Crim.App.1995) (<HOLDING>); Emerson v. State, 880 S.W.2d 759, 766-67
holding the evidence supported the police officers failure to follow the directives in the montgomery county police departments field operations manual holding that the court properly instructed jurors that the police officers were experts in determining a persons state of intoxication holding officers 60 hours of training at two different police departments that he had read a book on the subject and that the methods used in interpretation of bloodstains were of the type relied upon by experts in the field was sufficient holding that fire departments are analogous to police departments in this respect holding that an expert established a national standard of care for police officer training by testifying that police departments throughout the country commonly trained officers to deal with mentally distuibed persons and by naming several departments that offered such training