The Hacker's Encyclopedia 1998

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==Phrack Inc.== Volume Four, Issue Thirty-Eight, File 6 of 15 _____ BEATING THE RADAR RAP _____ / / \ / / \ ( 5/5 ) Part 2 of 2 : "The Technical Side" ( 5/5 ) \_/___/ \_/___/ by Dispater ______________________________________________________________________________ | | | Introduction | Welcome to the second installment in this series where we |______________| will briefly explore some of the technical sides to the operations, error analysis of the police traffic RADAR unit, the basics of how this technology was developed, then how it was implemented, a list of common RADAR errors, and finally the technical analysis of various types of traffic RADAR by National Highway Safety Administration. RADAR stands for Radio Detecting And Ranging. A traffic speed RADAR works under the principle of physicals called the "Doppler effect." This theory means that when a signal is reflected off of an object moving toward you, the signal will be at a higher frequency when it is closer to you than when the object is farther away or at the initial position. So the "Doppler effect" is THE basis for the use of the traffic speed RADAR. Right now in the United States, there are three bands that are allocated by the Federal Communications Commission (FCC) for "field disturbance sensors." These three bands have non-technical names, and all operate in the GigaHertz range (GigaHertz is a measure of frequency, i.e. 1 GHz = 1 billion cycles per second). The following is a list of the RADAR bands (as a point of reference FM radio modulates at 0.088 GHz to 0.108 GHz). ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: BAND : FREQUENCY NOTE ABOUT SPECIFIC BAND ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: X-Band : 10.525 GHz This is the frequency in which most RADAR units operate. K-Band : 24.150 GHz K-Band was developed to give a longer range of the beam. Ka-Band : 26.450 GHz This bandwidth is primarily for use with RADAR units that are used for "photo-speed traps." ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: "So if RADAR is so unreliable," you ask, "why don't we have planes crashing on a daily basis?" In the first place, TRAFFIC RADAR operates on a COMPLETELY different basis than, say, the type of RADAR that tracks weather or airplanes. The technology of traffic RADAR can in no way be compared to the accuracy of other types of RADAR. Traffic RADAR does NOT "sweep" like a regular RADAR. "Sweeping" means that the RADAR is picking up every single return signal it gets and plots them proportionally on a two-dimensional cathode ray tube. On the other hand, traffic RADAR uses a stationary beam. Also, traffic RADAR does not use a modulated beam like regular RADAR; it uses a constant beam. ***This is an important distinction because this means that if there are multiple images, the constant RADAR beam cannot distinguish between them!*** Furthermore, traffic RADAR is limited to things such as size. It must be able to fit inside a patrol car and it is also subject to cost. That means a municipality usually picks up the lowest bid it can get from various manufacturers. ______________________________________________________________________________ | | | Implementation of Traffic RADAR | It is important to note at this time that |_________________________________| while government standards for accuracy for military and commercial airline RADAR exist, traffic RADAR is NOT subject to ANY government standards whatsoever. An attempt was made to do this by the police and two government agencies, but were refused any type of compliance with traffic speed RADAR manufacturers and the Reagan administration. In the late 1970s, there was wide-spread publicity of about RADAR errors, including the well known tree clocked at 86-MPH in Florida. So, in 1979 the National Highway Safety Administration (NHSA) assigned to the National Bureau of Standards the task of testing all brands of traffic RADAR in use at that time for the purpose of discovering the source of these errors and proposing federal standards to eliminate them. In January of 1981, the proposed standards were published in the Federal Register. However, the Reagan administration took no action on the proposal (the last part of this file contains the profile from this report of various RADAR units). After THREE years of government inaction on the problem, the International Association of the Chief of Police (IACP) provided non-government standards by which all traffic RADAR units could be tested to assure accuracy: Volume I of the standards was published in April, 1984 and Volume II in June, of 1984. In June of 1986, the traffic RADAR manufacturers announced the formation of their own trade association, saying that they would not submit traffic RADAR units for IACP testing! Instead, they said they would use their own standards. So far, NO ONE has any idea of what these standards are; not the police, not the government and, most importantly, not the public! Basically, there are no performance requirements or standards for traffic RADAR and the claims of 86-MPH trees and 28-MPH houses cannot be refuted. ______________________________________________________________________________ | | | Common Traffic Radar Errors | Below is a list of common errors and how they |_____________________________| occur. This is the part of the article that must be used in conjunction with the previous file in this series. You must attempt, while pleading your case, to tie in some of the following errors to the situation you found yourself in when you got your speeding ticket. See Phrack #37 file #5 for details. "The Look-Past Error" Even when the RADAR operator aims his gun properly, the RADAR is subject to this type of error. This is caused by the RADAR reflecting off of a larger surface area in the background rather than the smaller reflective surface in the foreground. Evidence of this the Look-Past Error was printed in the October 1979 issue of "Car and Driver." The author measured the effectiveness of KR11 RADAR system against various vehicles. The author showed that the typical sedan did not show up on the RADAR until it was less that 1200 feet away, however, a Ford 9000 semi tractor trailer could be picked up at 7600 feet. "The Road Sign Error" Due to the reflectability of microwaves, road signs, buildings, billboards, large trees, and other stationary objects are a source of errors. "Radio Interference Error" According to the Texas Department of Public Safety, "UHF frequencies broadcast today can force RADAR to read various numbers when transmitted within the area." This type of interference could come from the radio within the patrol car, citizens band radio, or television stations. "Fan Interference Error" When the antenna is mounted inside the patrol car, "RADAR will have the tendency to read the pulse of the fan motor (air conditioner, heater, defroster)." This is a statement provided by the Texas Department of Public Safety who conducted a study of RADAR guns in 1987. The Texas Department of Public Safety offered no safeguard for this error. "Beam Reflection Error" Since microwaves are so readily reflected, the Texas Department of Public Safety cautioned mounting the antenna within the patrol car. One instructor said, "It is possible that a reflective path can be set up through the rear view mirror that will produce RADAR readings on the vehicles behind the patrol car when the RADAR is aimed forward. And those vehicles can be either coming or going since traffic RADAR cannot distinguish between the direction." "Double Bounce Error" Again, since microwaves are easily reflected, the operator must be aware of a "bad bounce" and an ordinary reflection. And, as stated before, since large objects are more efficient than smaller ones, microwaves are attracted to them more. So, in effect, you could have an initial RADAR bounce off of the target vehicle, then from the target vehicle to a house or a truck going the opposite direction, and finally back to the patrol car. This error will mathematically get larger the slower the target vehicle is moving. "The Cosine Error" This is a mathematical error that takes place when the RADAR gun attempts to calculate the trigonomic equation that is programmed into it. The RADAR gun measures the angle at which the target enters a point and then exits a point (i.e. 25 degrees). The cosine of 25 is .9063. The RADAR gun was designed to calculate the speed of the patrol car by multiplying the speed of the patrol car (i.e. 50 mph) and the cosine of the angle (.9063) and it gets the false speed of the patrol vehicle as 45mph. Therefore, when you subtract the patrol speed from the target speed (i.e. 50, the same as the patrol car) you get the false sense that the target vehicle is traveling 5mph faster than the patrol car. ______________________________________________________________________________ | | | Technical Analysis Report | Below is a copy of the report mentioned above |___________________________| was conducted by the NHSA. But first I will explain what some of the criteria were under the testing conditions. It is also important to note that ALL RADAR units were subject to "panning error" except the CMI Speedgun-6 and Speedgun-8 models. Panning error occurs when the RADAR antenna is aimed at it's own display console. Unintentional errors of this sort can be eliminated when police officers are given adequate training. TEST UNIT : Model and manufacturer of the police speed RADAR unit in question. BAND : The short hand used for determining the broadcast frequency of the RADAR unit. X-Band is 8.2-12.4 GHz. K-Band is 18.0-26.5 GHz. BEAM WIDTH : The number that is 1/2 of the actual beam width. In other words, if a RADAR manufacturer says the beam width is 24 degrees, the actual beam width is 48 degrees. Very deceptive, eh? SHADOWING ERROR : This occurs in moving mode only. It is the result of the RADAR mistaking another vehicle for it's ground reference and adding speed to the target reading. POWER SURGE : This occurs when the RADAR unit is first turned on. This also occurs when the "kill switch" is used to defeat RADAR detectors. Lag time for kill in the moving mode ranges from 1.5-5 seconds. EXTERNAL INTERFERENCE : The NBS test only used CB radio and police-band radio for "external interference." There are many other kinds of outside electromagnetic interference that may effect police RADAR. INTERNAL INTERFERENCE : Internal interference "may be caused by ANY electrical component or accessory in the vehicle, especially when the patrol car's primary power source is used to operate the RADAR. [It should be noted that TWO of MPH's K-55 RADAR units were tested. This demonstrates that each RADAR unit can contain its own quirks regardless of the fact that it can be from the same model from the same manufacturer.] _______________________________________________________________________________ NATIONAL BUREAU OF STANDARDS SUMMARY ON TRAFFIC RADAR _______________________________________________________________________________ TEST UNIT BAND BEAM WIDTH SHADOWING ERROR - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Kustom Signals MR-9 K 13.3 Minor POWER SURGE EXTERNAL INTERF. INTERNAL INTERF. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Switch-ON gave CB radio caused false CB radio caused stray reading of 7mph readings of up to 25' erroneous readings _______________________________________________________________________________ TEST UNIT BAND BEAM WIDTH SHADOWING ERROR - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - MPH Industries K-55 X 20.4 Added 12mph to target in one (first of two units) test POWER SURGE EXTERNAL INTERF. INTERNAL INTERF. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - No valid reading for CB radio caused false CB radio many 2.4 sec in moving mode readings of up to 20' erroneous readings _______________________________________________________________________________ TEST UNIT BAND BEAM WIDTH SHADOWING ERROR - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - MPH Industries K-55 X 24.6 Increased target speed 12-15mph (second of two units) about 20% of the time POWER SURGE EXTERNAL INTERF. INTERNAL INTERF. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2 sec delay in moving mode, CB radio caused false CB radio cause many 2.5 sec in stationary mode alarms up to 175' away erroneous readings _______________________________________________________________________________ TEST UNIT BAND BEAM WIDTH SHADOWING ERROR - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Decatur MV-715 X 17.5 Added 8-23mph to target in repeated testing POWER SURGE EXTERNAL INTERF. INTERNAL INTERF. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - No valid reading for Not effected by external Extreme interference 2+ seconds in moving mode CB radio from heater fan, ignition, & CB radio _______________________________________________________________________________ TEST UNIT BAND BEAM WIDTH SHADOWING ERROR - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - CMI Speedgun-6 X 18.8 Very severe, added 12-20 mph to target POWER SURGE EXTERNAL INTERF. INTERNAL INTERF. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 7 sec delay in moving mode, Not effected by external CB radio and police 2 sec delay in stationary CB radio radio boosts readings 20mph _____________________________________________________________________________ TEST UNIT BAND BEAM WIDTH SHADOWING ERROR - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - CMI Speedgun-8 X 18.6 target traveling 41mph shown as 74mph; target 30mph shown as 41mph POWER SURGE EXTERNAL INTERF. INTERNAL INTERF. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2 sec delay in moving mode, Not effected by external No adverse effect 1.2 sec delay in stationary CB radio noted _______________________________________________________________________________ TEST UNIT BAND BEAM WIDTH SHADOWING ERROR - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Kustom Signals MR-7 X 14.3 No effects noted POWER SURGE EXTERNAL INTERF. INTERNAL INTERF. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 25.4 sec delay in moving mode, Not effected by external Police band radio 0.6 sec delay in stationary CB radio caused intermittent increases of 10mph ______________________________________________________________________________ | | | In Closing... | I hope you have learned a little about how police speed |_______________| RADAR operates, the errors that they frequently incur, and possibly a way to avoid the highway robbery that occurs each time Officer Friendly decides to make a little extra dough for his "job security." Also, if you are interested in obtaining cheap traffic RADAR equipment to play with, you can write to: AIS SATELLITE INC., 106 N. Seventh Street, Perkasie, PA 18944. You can also call them for a catalog at (215)453-1400 or place orders at (800)AIS-2001. ______________________________________________________________________________