What role does the Superior Court play in a motion to suppress evidence?

In a hearing on a motion to suppress evidence, the superior court sits as a finder of fact. (People v. Lawler (1973) 9 Cal.3d 156, 160.) The trial court is vested with the power to judge the credibility of the witnesses, resolve any conflicts in the testimony, weigh the evidence and draw factual inferences. (Ibid.) On appeal all presumptions favor the trial court's findings on such matters, and they will be upheld if they are supported by substantial evidence. (Ibid.) The ultimate responsibility of the appellate court is to measure the facts, as found by the trier, against the constitutional standard of reasonableness. (Ibid.)