CALIBRATION AND CORRECTION OF MAGNETIC LOOP DETECTORS

A PROCEDURE IS DISCUSSED FOR THE CALIBRATION AND CORRECTION OF MAGNETIC LOOP DETECTORS. THE NEED FOR SUCH A CORRECTION ARISES FROM THE FACT THAT THE RISE TIME OF THE DETECTOR SIGNAL IS AN APPRECIABLE PERCENTAGE OF THE TYPICAL DURATION OF THE SIGNAL. THE CALIBRATION AND CORRECTION WERE CARRIED OUT BY COMPARING SIGNALS FROM MAGNETIC LOOPS WITH "BENCHMARK" SIGNALS OBTAINED AT THE SAME LOCATIONS BY USING PHOTOCELL DETECTORS, WHICH HAVE A CONSIDERABLY SHORTER SIGNAL RISE TIME. BOTH LOOPS AND PHOTOCELLS WERE ARRANGED IN PAIRS, ABOUT 13 FT APART, FORMING A DETECTOR "TRAP" THAT PERMITTED MEASUREMENT OF SPEEDS AND LENGTHS OF VEHICLES. THE SIGNALS WERE RECEIVED AND PROCESSED BY USING AN ON-LINE COMPUTER SYSTEM. A REGRESSION FIT OF LOOP AND PHOTOCELL DATA YIELDED AN EFFECTIVE LENGTH OF THE LOOP TRAP AND CORRECTIONS ON THE PULSE PROFILES THAT COULD MATCH THEM AS MUCH AS POSSIBLE WITH THE BENCHMARK PROFILES. /AUTHOR/

• Digital Copy:
  • Purchase a digital copy of this publication for $25 USD
• Supplemental Notes:
  • No 325, pp 30-35, 4 FIG, 3 TAB, 3 REF
• Authors:
  • Gazis, D C
  • Foote, R S
• Publication Date: 1970

Media Info

• Serial:
  • Highway Research Record
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Alignment; Calibration; Electromagnetic devices; Information processing; Loop detectors; Magnetic detectors; Photocells; Values in measurement; Vehicle detectors
• Uncontrolled Terms: Correction (Mathematics)
• Old TRIS Terms: Aligning
• Subject Areas: Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00225905
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Feb 12 1971 12:00AM