How does the Court of Appeal review a motion to suppress evidence on Fourth Amendment grounds?

"On appeal from a denial of a motion to suppress evidence on Fourth Amendment grounds, we review the historical facts as determined by the trial court under the familiar substantial evidence standard of review. Once the historical facts underlying the motion have been determined, we review those facts and apply the de novo standard of review in determining their consequences. Although we give deference to the trial court's factual determinations, we independently decide the legal effect of such determinations." ( People v. Esayian (2003) 112 Cal.App.4th 1031, 1038, 5 Cal.Rptr.3d 542.)