Feb 18, 8:16 AM (ET) By KIM CURTIS (AP) Sharon Rocha, mother of murder victim Laci Peterson, enters the San Mateo Superior Courthouse after... Full Image REDWOOD CITY, Calif. (AP) - A judge ruled that evidence police gathered using electronic devices to track Scott Peterson after his pregnant wife disappeared can be used in his murder trial, despite defense objections that the technology is unreliable. Because global positioning system technology has yet to be tested in state criminal court, prosecutors had to establish its reliability and demonstrate the technology was used correctly. Judge Alfred A. Delucchi decided Tuesday they had met those legal tests. Peterson's lawyer, Mark Geragos, tried to convince the judge that temporary glitches rendered unreliable the devices that Modesto police secretly attached to vehicles Peterson drove before his April 2003 arrest. Hugh Roddis, president of the company that sold Modesto police the three devices, said that covertly placed global positioning devices are a "good investigative tool." The satellite-based radio navigation system can pinpoint locations within feet and is in common use, including in commercial aircraft. Geragos seized on tracking errors in several of the devices Modesto police used, including one that he said didn't work for nearly three weeks. Roddis blamed the errors on inaccurate maps, a faulty wireless antenna and a bad microprocessor connection. http://apnews.myway.com/article/20040218/D80PMBH01.html