Chesterfield Man arrested for open carrying NEAR a school

[wylde007]

I believe all civilian GPS units lack the ability to be precise.

All civilian GPS "navigators" lack the ability to be precise.

GPS transmits in several simultaneous bands. It is possible to shut off the ones which civilians receive - leaving the military with the only vector location technology. Convenient for them.

Some civilian GPS (survey-grade) allows positional accuracy to within 1cm, or about the head of a dime.

 

[2a4all]

I believe all civilian GPS units lack the ability to be precise. Do you really want to carry something that may say you were on school property when you were actually really 50 feet away?

The only solution is never walk anywhere. Just stay in your car. That's why God made drive throughs.

I think you've got it backwards, Fenris. The question is: Do you want to rely on something that says you're 50' away from school property when you're actually walking on it?

I agree. Stay in your car!

 

[wrightme]

I believe all civilian GPS units lack the ability to be precise. Do you really want to carry something that may say you were on school property when you were actually really 50 feet away?

The only solution is never walk anywhere. Just stay in your car. That's why God made drive throughs.

All civilian GPS "navigators" lack the ability to be precise.

GPS transmits in several simultaneous bands. It is possible to shut off the ones which civilians receive - leaving the military with the only vector location technology. Convenient for them.

Some civilian GPS (survey-grade) allows positional accuracy to within 1cm, or about the head of a dime.

Not accurate at all. (the statement that is...)

GPS is a time-difference location system. "Selective Availability" used to alter the time slightly to all except military grade units that could receive an encrypted "accuracy" signal. Yet, this was "selective," and not always in use.
IIRC, this is no longer the case, and civilian GPS is quite accurate. Survey-grade GPS likely uses a WAAS signal (I think that is the term) that "accurizes out" any error anyway. That is sometimes available to civilian gps, but costs more.

http://www8.garmin.com/aboutGPS/

Intentional degradation of the satellite signal - Selective Availability (SA) is an intentional degradation of the signal once imposed by the U.S. Department of Defense. SA was intended to prevent military adversaries from using the highly accurate GPS signals. The government turned off SA in May 2000, which significantly improved the accuracy of civilian GPS receivers.

I would expect 1-3 meter or LESS accuracy from a decent civilian GPS.

Newer Garmin GPS receivers with WAAS (Wide Area Augmentation System) capability can improve accuracy to less than three meters on average. No additional equipment or fees are required to take advantage of WAAS. Users can also get better accuracy with Differential GPS (DGPS), which corrects GPS signals to within an average of three to five meters.

 

[Fenris]

I think you've got it backwards, Fenris. The question is: Do you want to rely on something that says you're 50' away from school property when you're actually walking on it?

I agree. Stay in your car!

Yes, this too would be bad. The problem with inaccuracy, is that it just isn't accurate.

 

[paramedic70002]

Now y'all have me wondering.

My wife's Tomtom is a few years old but by the graphics you can't zoom in much better than to determine your location within 100 feet IIRC. Not much better on my cell, a Sprint Samsung Instinct HD, which is only a few months old.

Not much better on the stereo/GPS in my EMS agency's Zone car, about five years old, and it is consistently 200 yards off target. I can't find the owners manual, or one online, but don't see any way in the menu to calibrate it.

 

[wrightme]

Now y'all have me wondering.

My wife's Tomtom is a few years old but by the graphics you can't zoom in much better than to determine your location within 100 feet IIRC. Not much better on my cell, a Sprint Samsung Instinct HD, which is only a few months old.

Not much better on the stereo/GPS in my EMS agency's Zone car, about five years old, and it is consistently 200 yards off target. I can't find the owners manual, or one online, but don't see any way in the menu to calibrate it.

200yds off-target? I can't even call that a gps.

One method of checking is to display the actual coordinates the gps is displaying, and actually plot them on a no-kidding map. The functionality where the specific unit you have is plotting might be "broken." My Magellan car gps typically shows a travel path near the road that my car is on. It still serves its purpose. I have not used my eTrex vista in a few years, but I recall it was quite accurate. Most likely, accurate enough to keep to a "school-zone-exclusive" route of travel.

 

[TFred]

Now y'all have me wondering.

My wife's Tomtom is a few years old but by the graphics you can't zoom in much better than to determine your location within 100 feet IIRC. Not much better on my cell, a Sprint Samsung Instinct HD, which is only a few months old.

Not much better on the stereo/GPS in my EMS agency's Zone car, about five years old, and it is consistently 200 yards off target. I can't find the owners manual, or one online, but don't see any way in the menu to calibrate it.

I agree with wrightme, that's horrible.

There are two parts to a GPS showing you where you are. 1) is where you actually are, in terms of Latitude and Longitude, and 2) is the map the unit uses, and how accurate the details on the map are displayed.

Your GPS must have both correct in order for you to accurately see where you are.

The GPS technology has been well discussed already. The map side of things, not so much. It is fairly important to keep updated maps, which unfortunately, nearly always requires more money. I do believe Garmin has a lifetime update option for some of their products, but I don't know the specific details.

TFred

 

[peter nap]

200yds off-target? I can't even call that a gps.

One method of checking is to display the actual coordinates the gps is displaying, and actually plot them on a no-kidding map. The functionality where the specific unit you have is plotting might be "broken." My Magellan car gps typically shows a travel path near the road that my car is on. It still serves its purpose. I have not used my eTrex vista in a few years, but I recall it was quite accurate. Most likely, accurate enough to keep to a "school-zone-exclusive" route of travel.

My Garmin which granted was on the expensive side, is 2 feet off (Maybe a few inches, I can't tell) from where I'm standing right now. That's close enough for me.

 

[paramedic70002]

I have to respond throughout the whole County, so I rely on the GPS to get me where I'm going, but once I get within a half mile I start checking addresses. It's so much fun to hear, "You have arrived at your destination" when the numbers aren't even close. At least it tells me which side of the road to look. Unfortunately many rural denizens must be in the witness protection program because they either have no visible address or a completely wrong address on their mailbox. This despite that when the County went to "911 addressing" they bought every residence a sign placard and mailed it to them.

 

[Grapeshot]

I have to respond throughout the whole County, so I rely on the GPS to get me where I'm going, but once I get within a half mile I start checking addresses. It's so much fun to hear, "You have arrived at your destination" when the numbers aren't even close. At least it tells me which side of the road to look. Unfortunately many rural denizens must be in the witness protection program because they either have no visible address or a completely wrong address on their mailbox. This despite that when the County went to "911 addressing" they bought every residence a sign placard and mailed it to them.

How long ago did this occur? Have lived in the same house for 27 years and do not recall ever receiving anything from Chesterfield County regarding this.

GPSs have told me "arriving now" when I was 1/2 mile away, or "on right" when the destination was on the left. Have also been told to "turn now" when I was in the middle of a bridge and then taken down a long residential loop road on one side of the highway when restaurant location was on the opposite side in a shopping center. None of these where new, recently built locations. Realize that part of the problem was in the maps and part of the problem was in the system(s) used by the GPS.

 

[peter nap]

How long ago did this occur? Have lived in the same house for 27 years and do not recall ever receiving anything from Chesterfield County regarding this.

GPSs have told me "arriving now" when I was 1/2 mile away, or "on right" when the destination was on the left. Have also been told to "turn now" when I was in the middle of a bridge and then taken down a long residential loop road on one side of the highway when restaurant location was on the opposite side in a shopping center. None of these where new, recently built locations. Realize that part of the problem was in the maps and part of the problem was in the system(s) used by the GPS.

I think that's standard Grapeshot. When they went to the 911 system, I got one at the burb house. Tossed it in the trash and kept using the old address.
They fussed about it once and I told them I didn't move.

 

[Grapeshot]

I think that's standard Grapeshot. When they went to the 911 system, I got one at the burb house. Tossed it in the trash and kept using the old address.
They fussed about it once and I told them I didn't move.

As I had always understood it, the Post Office was responsible for assigning/approving all mailing addresses - that being the control factor in whether you got your mail or not.

If the county has any conflict with the assignment of addresses, seems to be that it would have been much more prudent and simpler for the county to adjust/adapt the own procedures.

 

[peter nap]

As I had always understood it, the Post Office was responsible for assigning/approving all mailing addresses - that being the control factor in whether you got your mail or not.

If the county has any conflict with the assignment of addresses, seems to be that it would have been much more prudent and simpler for the county to adjust/adapt the own procedures.

The County had a lot of issues. Being a family board, I won't relay the response to them. On voting day the poll officers know my response by heart..."Do you want my real address or the one the county says I have":lol:

The Post Office threatened to not deliver the mail until I told them I'd change my mail for all my normal bill senders to "General Delivery".

They backed off then.

 

[user]

Really good civilian GPS units, e.g., used for surveying and field engineering applications, are capable of accuracy to within half a millimeter. But they use a technique called "real time kinematic" measurement, which relies on the carrier wave of the transmission rather than by matching psuedorandum transaction identification numbers. They take anywhere from forty-five minutes to three days, while they remain absolutely unmoved, to make that kind of measurement.

Garmin (the only specific brand of handheld device I'm familiar with) can get within a few inches by taking repeated measurements while remaining absolutely unmoved, over a course of a few minutes. The process can be repeated to improve accuracy over time. Ordinarily, just walking around, the Garmin devices are accurate to within about eight to ten feet; that improves if you're using a device-powered external antenna to about three or four feet.

So, if someone were charged with the crime of walking too close to a "gun free school zone", and I were hired to represent him, I could use my device in location-averaging mode to identify the specific location of the property boundaries and his location at the time of the incident. That takes hours, mainly because of all the walking around and time-consuming measurements. That data can be plotted on a USGS topographical map, which is admissible into evidence because it's prepared by the government. The points plotted can be separately authenticated by my "paralegal/research assistant" (since he doesn't work for me on a W-2 basis, it's illegal for me to call him an "investigator", because he doesn't have a license from DCJS) as a witness to the process (i.e., I do the investigation and he observes the process).

I have such a case right now, the charge is reckless handling of a firearm while hunting. The complaining witness was over a quarter mile away at the time of the incident, and on the other side of some forested areas. The collected GPS data can establish where my client's shotgun was, where the complainant was, and where the relevant structures on the land were. (Without the need for line-of-sight measurements.)

My point is that even though my unit is supposed to be optimized for hiking and such, I wouldn't trust it for walking past a GFSZ, unless I had at least a twelve foot buffer between me and the zone.

 

[wylde007]

Not accurate at all. (the statement that is...)

100% accurate and backed by industry testimony and performance.

GPS is a time-difference location system. "Selective Availability" used to alter the time slightly to all except military grade units that could receive an encrypted "accuracy" signal. Yet, this was "selective," and not always in use.
IIRC, this is no longer the case, and civilian GPS is quite accurate. Survey-grade GPS likely uses a WAAS signal (I think that is the term) that "accurizes out" any error anyway. That is sometimes available to civilian gps, but costs more.

WAAS is a ground-based correction, which still only improves "navigation" to within a few meters, at best and under optimal conditions. Selective Availability only hindered survey-grade applications at any length. It required long setup and occupy times in order to increase locational confidence for control networks. Once the control network was set up, and assuming you had at least two (2) receivers, you could perform sub-meter survey operations. Sub-centimeter still required long occupations of stations.

I would expect 1-3 meter or LESS accuracy from a decent civilian GPS.

That's not a reasonable expectation but I hear it all the time from people who say "I have a GPS". 3 meters is almost ten feet. Considering that in most municipalities the distance between the curb and right-of-way is typically ten feet, an ambiguity of 3 meters could easily be the difference between being "on" school property or "off".

I have been to conferences on GPS and I use survey-grade GPS on a regular basis.

Survey-grade typically receives and rectifies more satellite signals at a time (up to twelve) and is more accurate when either used in a static setup with multiple stations OR when linked to an RTK (Real-Time Kinematic) network which broadcasts a radio signal and is generally available by subscription to correct ground surveys by transmitting their exact geodetic location at least once ever 60 seconds.

GPS navigators by Garmin, Magellan, Tom-tom... they do not have access to this ground-based corrected. Yes, WAAS can help some, but I have used a personal "navigator" to compare locations on the ground to conventional survey data - and under OPTIMAL conditions (and utilizing WAAS-corrections) I was able to achieve about a 5-meter (±2m) confidence.

I hope this helps you understand GPS a little better than Wikipedia.

BTW, I am a licensed surveyor in the Commonwealth of Virginia.

 

[grylnsmn]

100% accurate and backed by industry testimony and performance.WAAS is a ground-based correction, which still only improves "navigation" to within a few meters, at best and under optimal conditions. Selective Availability only hindered survey-grade applications at any length. It required long setup and occupy times in order to increase locational confidence for control networks. Once the control network was set up, and assuming you had at least two (2) receivers, you could perform sub-meter survey operations. Sub-centimeter still required long occupations of stations.That's not a reasonable expectation but I hear it all the time from people who say "I have a GPS". 3 meters is almost ten feet. Considering that in most municipalities the distance between the curb and right-of-way is typically ten feet, an ambiguity of 3 meters could easily be the difference between being "on" school property or "off".

I have been to conferences on GPS and I use survey-grade GPS on a regular basis.

Survey-grade typically receives and rectifies more satellite signals at a time (up to twelve) and is more accurate when either used in a static setup with multiple stations OR when linked to an RTK (Real-Time Kinematic) network which broadcasts a radio signal and is generally available by subscription to correct ground surveys by transmitting their exact geodetic location at least once ever 60 seconds.

GPS navigators by Garmin, Magellan, Tom-tom... they do not have access to this ground-based corrected. Yes, WAAS can help some, but I have used a personal "navigator" to compare locations on the ground to conventional survey data - and under OPTIMAL conditions (and utilizing WAAS-corrections) I was able to achieve about a 5-meter (±2m) confidence.

I hope this helps you understand GPS a little better than Wikipedia.

BTW, I am a licensed surveyor in the Commonwealth of Virginia.

Let me second all of what wylde007 posted.

I used to work developing railroad track geometry systems that required locating a section of track down to a 1-foot resolution, and I dealt with DGPS systems on a signals level to do it. Civilian-grade GPS systems marketed for home/car use are really only meant to put you in the general area. Even then, they do a lot of guessing to put you on the right street. And that's just dealing with the Lat/Long coordinates that it calculates.

It gets even more complicated when you factor in not just the error from the GPS calculations, but also the error in the consumer-grade maps that are stored in the GPS for display. Those maps aren't meant to give you accuracy closer than a couple dozen meters. (For example, my car's GPS reports the correct Lat/Long for my house, but the maps think that my address is 2-3 houses farther down the street.)

If you want to be able to get the level of accuracy needed to definitively say that you are not on school property, you need industrial-grade hardware and incredibly accurate maps. Otherwise, you are risking everything on the error inherent to your setup.

 

[peter nap]

100% accurate and backed by industry testimony and performance.WAAS is a ground-based correction, which still only improves "navigation" to within a few meters, at best and under optimal conditions. Selective Availability only hindered survey-grade applications at any length. It required long setup and occupy times in order to increase locational confidence for control networks. Once the control network was set up, and assuming you had at least two (2) receivers, you could perform sub-meter survey operations. Sub-centimeter still required long occupations of stations.That's not a reasonable expectation but I hear it all the time from people who say "I have a GPS". 3 meters is almost ten feet. Considering that in most municipalities the distance between the curb and right-of-way is typically ten feet, an ambiguity of 3 meters could easily be the difference between being "on" school property or "off".

I have been to conferences on GPS and I use survey-grade GPS on a regular basis.

Survey-grade typically receives and rectifies more satellite signals at a time (up to twelve) and is more accurate when either used in a static setup with multiple stations OR when linked to an RTK (Real-Time Kinematic) network which broadcasts a radio signal and is generally available by subscription to correct ground surveys by transmitting their exact geodetic location at least once ever 60 seconds.

GPS navigators by Garmin, Magellan, Tom-tom... they do not have access to this ground-based corrected. Yes, WAAS can help some, but I have used a personal "navigator" to compare locations on the ground to conventional survey data - and under OPTIMAL conditions (and utilizing WAAS-corrections) I was able to achieve about a 5-meter (±2m) confidence.

I hope this helps you understand GPS a little better than Wikipedia.

BTW, I am a licensed surveyor in the Commonwealth of Virginia.

Thanks Wylde! I was hoping you'd chime in.
My GPS (not a navigator) was expensive and I have no idea what it uses to determine location but when I checked it against a Topo Map while it was n a tripod, it was very close.

The problem is I'm working on a project now where I cannot set it on a tripod and even if I did, two feet might as well be a mile. So I plan on using my laser rangefinder and triangulate on the object.

I' may PM you about this because I still have to find an accurate plat to find the points triangulate from. This has to be very close. I know the rangefinder is accurate because I can calibrate it to a tape.

 

[user]

High-end Garmin models do use WAAS, but their advertising still only promises eight to ten feet proximity to true location. By the repeated use of "waypoint averaging", I've been able to get within eight inches (I think). Still, not good enough to see whether you're walking within 1000 feet of the perimeter of school property, unless you provide a buffer of three or four yards.

You know, it just occurred to me. Given all the dangers associated with schools, as recited in the federal statute, I have become convinced that the risks outweigh the benefits of schools. They are clearly too dangerous to society and cause all sorts of harms to children. Since schools cause so much harm to children, we should clearly outlaw schools. I've become an advocate for school-control.

 

[paramedic70002]

Hey Grapeshot and Peter Nap,

The County I'm talking about is Southampton.

Not sure how you can have two addresses. When all the Counties around here went 911, they contracted with a mapping consultant agency. Grids were used to assign house numbers based on your location in the grid and whether your road was primarily N-S or E-W. This eliminated Route and Box numbers, and situations where houses being built between existing addresses having addresses like "Rout 3 Box 117 A 1/2." The old addresses were ELIMINATED. Stand by...

There were a few holdouts that didn't want to change their addresses to the new system, but they eventually did, or at least displayed both. The bottom line is the old address IS NO LONGER VALID.

Now you can be as stubborn as you want to be, but let me explain why you're wrong. Police, fire and EMS use the "911" address to find you. As time goes by, they either grow unfamiliar with the old system, or personnel change. If you like the idea of emergency services being able to find you in a timely manner, you will use the new address. Further, if you think emergency services should find your neighbor in a timely manner, you will use the new address. It's so much easier to find an address when I can "count it down."

When I am responding to an emergency, I tend to disregard houses with no addresses. I figure if you want me to actually show up when you call 911, you'll either have your CORRECT address displayed or have someone waiting outside to flag me down.

You've hit one of my pet peeves with this address issue. Bottom line, if you're not using the County assigned address, you're wrong and you're gambling with your life, as well as the lives of your family and neighbors. Go down to Wally World or Mom & Pop's Hardware and get you some numbers that are big, and either reflective or in contrasting colors like black/white in fore and back ground. Something that you can read in the rain going 75 mph at night.

 

[peter nap]

Hey Grapeshot and Peter Nap,

Boy did you hit a nerve Paramedic:lol:

Not sure how you can have two addresses.

I don't, I have one.

There were a few holdouts that didn't want to change their addresses to the new system, but they eventually did, or at least displayed both. The bottom line is the old address IS NO LONGER VALID.

Says who. I don't care what the County says! They can go pound sand.

Now you can be as stubborn as you want to be, but let me explain why you're wrong. Police, fire and EMS use the "911" address to find you.

I can stop you right there. I've never dialed 911 and never will. As a matter of fact, If you dial 911 on my phone, you get Grapeshot as my wife found out one day when I was videoing a car accident and she wanted to call the rescue squad. (I wasn't going to call them, there were other people around and I was busy)


, .

...

Now before you start the ...Oh you'll find out when you need us...

A few years ago I got appendicitis. It was deer season so I put it off for a few days and it burst.
I didn't dial 911. Went to the hospital, had them take it out and checked myself out a few hours later...and went hunting.

Same thing with a heart attack, gunshot, two broken legs and a finger nearly severed.
Some people live their lives on their terms...not the governments.

I will never need or want you! (In a professional sense, you're always welcome otherwise:lol