Radar and how it works

[Dragon]

I know the answers :laughing and I'm too lazy to type it out.

At a BARF meet a while back one guy "who's neighbor who is a CHP" explained that he can track and 'lock' up to three targets at a time.

I didn't get into it with him.

Also are any LEO's using POP mode?

(Christian Doppler (1803-53) )

 

[Brash47]

Ok, someone is going to have to answer this one for me....we don't use radar....

 

[Dragon]

Ok, someone is going to have to answer this one for me....we don't use radar....

Some help you are Mr. Mod :laughing

Radar myths:

1- Just because a cop is behind you doesn't mean he is using it on you (other than sensing his/her vehicles speed). However, the cops that like to have fun with people have the tendency when they see a car with a RADAR detector is to get behind the said person and turn their radar off and on and watch the pretty lights on your dash board. They will follow you for miles and when you look back they are snickering :laughing

2- Even if you bike is all carbon fibre- you will be picked up on the radar. Unless the shapes are radar deflecting and the surface is radar absorbing- you are screwed. It is sensitive enough that I have heard a joggers shoes when the volume was turned up. All the theories of chaff and tinfoil hats is BS :jaded

3- Locking three targets: BS- there is only one lock button. If a group of bikes is heading at you and the LEO locks the target (lead bike) w/ the radar and visually estimate the speed the other riders are at- yes you are all screwed.

--------

Radar works with vehicles that are moving towards or away from the RADAR unit. Most LEO's leave their RADAR off, until they see an interseting target. It's turned on and then it's locked (Instant on)

POP mode, is a RADAR signal that is a very short burst/emmission that cannot be detected by most detectors. The owners manual on those models usually state that POP mode is for an estimate and should not be used for evidencial purposes.

 

[rumpofsteelskin]

Even if you bike is all carbon fibre- you will be picked up on the radar. Unless the shapes are radar deflecting and the surface is radar absorbing- you are screwed.

...

All the theories of chaff and tinfoil hats is BS

...

Aw, damn.

<puts pizza slice back in tinfoil and removes "stealth bomber" panels bought on late-nite TV. While doing so, notices that they say "carpet fiber," not "carbon fiber.">

 

[deaconblues]

Just be glad they havent put radar receivers along the sides of the road.

a German engineering team showed that you can detect 'stealthed' aircraft by catching the radar returns that were not reflected back at the original emitter. If you know the position and vector of the emitter, and then collate the data from multiple receivers, you get a 'holographic' picture of what did the reflecting.

which means that if you put this on a roadway, and a cop lit off a radar 'ping' - the receivers would then get a reading off of all of the vehicles tagged by that radar pulse.

scary.

 

[recursive]

Just be glad they havent put radar receivers along the sides of the road.

a German engineering team showed that you can detect 'stealthed' aircraft by catching the radar returns that were not reflected back at the original emitter. If you know the position and vector of the emitter, and then collate the data from multiple receivers, you get a 'holographic' picture of what did the reflecting.

which means that if you put this on a roadway, and a cop lit off a radar 'ping' - the receivers would then get a reading off of all of the vehicles tagged by that radar pulse.

scary.

Why bother transmitting a ping at all when it's already being done for you by existing transmitters
http://www.roke.co.uk/sensors/stealth/celldar.asp

(probably wouldn't be of the necessary accuracy for the purpose of giving speeding tickets, but it is a rather neat/scary idea.)

 

[NorCalBusa]

The radars on the market today lock the Strongest (best reflection) and if so equiped- Fastest (not the first, second or third fastest or first, second or third target- but the absolute Fastest target anywhere within the return.

Some radars have one antenna (forward facing) and some have two (add a rear). Most read one antenna at a time.

However, the Stalker DSR 2X reads front strongest, front fastest, rear strongest, rear fastest, closing or same lane- all at the same time, while the patrol car is moving and it and it aquires in about 1/2 a second. Needless to say; his is one bad mutha of a radar...

 

[xgambit]

Aw, damn.

<puts pizza slice back in tinfoil and removes "stealth bomber" panels bought on late-nite TV. While doing so, notices that they say "carpet fiber," not "carbon fiber.">

:laughing

 

[NorCalBusa]

How does it work?

Radar transmits on what is close to microwave frequency (X, K and Ka band), with each having advantages and disadvantages. Ka provides the best overall performance. This beam is usually 12 degrees wide.

The unit transmits a wave and, once reflected off a MOVING surface, the waves are either compressed (target is closing) or expanded (target is moving away). This wave change is called "Doppler shift". A great example is a car going by with it's horn blasting or a train going by- the sound is unchanged on-board, but rises then falls as it passes.

In Moving radar, a second wave is sent (called "Low Doppler") to determine the speed of the patrol car/motorcycle. Just what you would figure; this Low Doppler simply bounces a wave off the pavement and does the same math to determine speed of the patrol car. The two signals' (Low and High Doppler) delta determines the target speed.

LIDAR works a bit differently; a timed pulse of infrared light is transmitted and reflected by the target. This pulse goes out and is timed for its return; some simple math determines the speed toward or away from the unit. At 1000', the beam is about 3.5' wide. There is no Moving LIDAR... yet.

Both units measure the speed of the target towards the unit- this provides a "cosine error" unless the target is headed directly towards (or away from) the unit. This error is on the side of the target (that is, is to the advantage of the target- reading a slower speed than actual); the greater the cosine error, the greater the advantage to the target. To illustrate, imagine going down a six lane freeway (three lanes each way), a 1/2 mile out there is only 1-3 degrees of error; but up close, at say 100 feet, the error is significant.

POP, Instant on, Alarms and Thresholds have been prohibited by the IACP as they disallow for some necessary radar testimonial evidence.

The operator (in California) needs to have completed a 24 hour class (a six hour add-on for LIDAR) to qualify in its use. Any cop can show you how to use one- you'll be picking out targets in under 5 minutes... this stuff is good, really good- and in the hands of an expert user; get out your license and press hard.

Yeah, yeah:
-this is me talking, not that of any law agency, manufacturer, court or otherwise.

- all this info is in the public domain.

 

[Dragon]

How does it work?

Radar transmits on what is close to microwave frequency (X, K and Ka band), with each having advantages and disadvantages. Ka provides the best overall performance. This beam is usually 12 degrees wide.

The unit transmits a wave and, once reflected off a MOVING surface, the waves are either compressed (target is closing) or expanded (target is moving away). This wave change is called "Doppler shift". A great example is a car going by with it's horn blasting or a train going by- the sound is unchanged on-board, but rises then falls as it passes.

In Moving radar, a second wave is sent (called "Low Doppler") to determine the speed of the patrol car/motorcycle. Just what you would figure; this Low Doppler simply bounces a wave off the pavement and does the same math to determine speed of the patrol car. The two signals' (Low and High Doppler) delta determines the target speed.

LIDAR works a bit differently; a timed pulse of infrared light is transmitted and reflected by the target. This pulse goes out and is timed for its return; some simply math determines the speed toward or away from the unit. At 1000', the beam is about 3.5' wide. There is no Moving LIDAR... yet.

Both units measure the speed of the target towards the unit- this provides a "cosine error" unless the target is headed directly towards (or away from) the unit. This error is on the side of the target (that is, is to the advantage of the target- reading a slower speed than actual); the greater the cosine error, the greater the advantage to the target. To illustrate, imagine going down a six lane freeway (three lanes each way), a 1/2 mile out there is only 1-3 degrees of error; but up close, at say 100 feet, the error is significant.

POP, Instant on, Alarms and Thresholds have been prohibited by the IACP as they disallow for some necessary radar testimonial evidence.

The operator (in California) needs to have completed a 24 hour class (a six hour add-on for LIDAR) to qualify in its use. Any cop can show you how to use one- you'll be picking out targets in under 5 minutes... this stuff is good, really good- and in the hands of an expert user; get out your license and press hard.

Yeah, yeah:
-this is me talking, not that of any law agency, manufacturer, court or otherwise.

- all this info is in the public domain.

:thumbup :thumbup

BTW: You go back east- they have dummy patrol cars set up on the expressway (NJSP)- junker cars with dumbies in them- you hit the fourth car and the head on the dumbie movies as you are getting locked.

Some states work RADAR out of the back of what looks like a "stalled" big rig on the side of the highway.



This has to be the most classic shot from Texas:

 

[NorCalBusa]

LOL!

In Texas, they make no bones about speed enforcement as a revenue stream.

Here- a mere $20 of a $300 ticket goes back to a city (none, zip, nada, zilch goes back to CHP- they are funded 100% by DMV fees and grants).

Folks love to wail the "revenue stream is the motivation" cry as the driver; it's simply not the case here.

 

[Dragon]

LOL!

In Texas, they make no bones about speed enforcement as a revenue stream.

Here- a mere $20 of a $300 ticket goes back to a city (none, zip, nada, zilch goes back to CHP- they are funded 100% by DMV fees and grants).

Folks love to wail the "revenue stream is the motivation" cry as the driver; it's simply not the case here.

I believe the TX constables are paid on a commision... (warrants, traffic etc>)

But in CA- 50% goes to the state general fund... but that was a few years back

 

[NorCalBusa]

I think the BIG motivator in Texas is using speed enforcement for interdiction on Hwy 35, which runs from Garagozo Mexico to and beyond Kansas.

Now THAT's where the real money is!