View Poll Results: How often are the new internal GPS abilities of a locator used?

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  • Often?

    1 12.50%
  • Sometimes?

    1 12.50%
  • Never?

    5 62.50%
  • Just on SUE projects?

    1 12.50%
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Thread: Is anyone using the new Internal GPS abilities in the newer models of locators?

  1. #1
    TCY
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    Default Is anyone using the new Internal GPS abilities in the newer models of locators?

    Often?

    Sometimes?

    Never?

    Only for SUE projects?

  2. #2
    Conservative Meanie ifinditunderground's Avatar
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    Default Re: Is anyone using the new Internal GPS abilities in the newer models of locators?

    Never, and certainly not for SUE projects.
    There is a fine line between "Hobby" and "Mental Illness."
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  3. #3
    Senior Member ProfessionalLocator's Avatar
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    Default Re: Is anyone using the new Internal GPS abilities in the newer models of locators?

    Do not have such equipment and on one call marking do not see any use for it. People dig off of marks, not gps records. Error tolerance for marks is often 12 to 24 inches so any gps record has to have the ability to be exact within a very small area. Then it is only what you recorded and digging is by the marks. Nice toy but just do not see any practical use for our industry.

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    Default Re: Is anyone using the new Internal GPS abilities in the newer models of locators?

    I have clients request GPS marking/mapping from time to time, mostly engineers and I believe our new Metro. VLOC-5000 will mark way points, but I have not used it yet. I usually will have the client have their surveyor pick up my paint behind me, much faster as I am not a surveyor!

  5. #5
    Senior Member ProfessionalLocator's Avatar
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    Default Re: Is anyone using the new Internal GPS abilities in the newer models of locators?

    The thing about GPS information is that it is dependent on the military GPS system. The GPS receivers are restricted to the civilian transmission band which ahs built into it the ability to degrade the signal on command. This is so our enemies cannot use our GPS system to direct an attack on us. GPS information can be used but the old school systems must still be used as a backup should the GPS system be made unavailable.

  6. #6
    Right Wing Conspirator GWJ_CAS's Avatar
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    Default Re: Is anyone using the new Internal GPS abilities in the newer models of locators?

    Quote Originally Posted by ProfessionalLocator View Post
    The thing about GPS information is that it is dependent on the military GPS system. The GPS receivers are restricted to the civilian transmission band which ahs built into it the ability to degrade the signal on command. This is so our enemies cannot use our GPS system to direct an attack on us. GPS information can be used but the old school systems must still be used as a backup should the GPS system be made unavailable.
    Not so much...the signal degradation was called "Selective Availability"...Selective Availability (SA) was an intentional degradation of public GPS signals implemented for national security reasons. In May 2000, at the direction of President Bill Clinton, the U.S government discontinued its use of Selective Availability in order to make GPS more responsive to civil and commercial users worldwide. In September 2007, the U.S. government announced its decision to procure the future generation of GPS satellites, known as GPS III, without the SA feature. Doing this will make the policy decision of 2000 permanent and eliminate a source of uncertainty in GPS performance that had been of concern to civil GPS users worldwide.

    Military GPS systems operate in Grid (MGRS), a different geopositioning system whereas civilian GPS operates in more traditional Lat/Lon (although most can access UTM/MGRS and other formats through menu settings). The accuracy of the GPS signal in space is actually the same for both the civilian GPS service (SPS) and the military GPS service (PPS). However, SPS broadcasts on one frequency, while PPS uses two. This means military users can perform ionospheric correction, a technique that reduces radio degradation caused by the Earth's atmosphere. With less degradation, PPS provides better accuracy than the basic SPS. Many users can enhance the basic SPS with local or regional augmentations (WAAS, VRS, CORS, NTRIP & Others). Such systems boost civilian GPS accuracy beyond that of Military PPS to the range of sub-centimeter (millimeter accuracy) with post-processing. With new dual frequency civilian GPS receivers that can receive real-time PPP signals and the number of "birds" up there (GPS/GNSS) there is no accuracy difference between military and civilian...sorry

  7. #7
    Mke
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    Default Re: Is anyone using the new Internal GPS abilities in the newer models of locators?

    Unfortunately I believe the GPS capabilities of the new equipment are just gimmicks. Does it have the ability to connect to external GPS antenna? Yes. Can it collect data from this receiver? Yes. Unfortunately, they don't go into the finer details of how GPS works and the accuracy of the information you are getting.

    PL is basically right about the current system is based on our Military satelites, however, there are systems out there that use the Russian satelites as well. Don't know if this is any more stable then ours, but it is what it is. The Professional Survey GPS recievers can plot points with sub-meter accuracy (+/- .03in) That is not bad at all. Most commercial recievers that are compatible with our equipment are not sub-meter. they are +/- 7meters (typically around 10' or so depending on situation).

    The biggest issue is that their is no set measurable distance between the point the locator Receiver and the GPS receiver. You need the GPS receiver as high as you can get it. Most of these add on GPS receivers clip onto one's hat. That distance not only changes vertically, but it changes horizontally. You can fix the receiver the locator receiver, but at a lower height, you are going to run into poor PDOP. If you can collect the data at this point the variance of error is greater.

    Most Engineering firms want as accurate as possible information. This requirement is typically sub-meter, hence, no push for the locators to be attempting to gather that information.

    Hopefully I didn't confuse the issue.

    mke

  8. #8
    Right Wing Conspirator GWJ_CAS's Avatar
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    Default Re: Is anyone using the new Internal GPS abilities in the newer models of locators?

    Quote Originally Posted by Mke View Post
    Unfortunately I believe the GPS capabilities of the new equipment are just gimmicks. Does it have the ability to connect to external GPS antenna? Yes. Can it collect data from this receiver? Yes. Unfortunately, they don't go into the finer details of how GPS works and the accuracy of the information you are getting.

    PL is basically right about the current system is based on our Military satelites, however, there are systems out there that use the Russian satelites as well. Don't know if this is any more stable then ours, but it is what it is. The Professional Survey GPS recievers can plot points with sub-meter accuracy (+/- .03in) That is not bad at all. Most commercial recievers that are compatible with our equipment are not sub-meter. they are +/- 7meters (typically around 10' or so depending on situation).

    The biggest issue is that their is no set measurable distance between the point the locator Receiver and the GPS receiver. You need the GPS receiver as high as you can get it. Most of these add on GPS receivers clip onto one's hat. That distance not only changes vertically, but it changes horizontally. You can fix the receiver the locator receiver, but at a lower height, you are going to run into poor PDOP. If you can collect the data at this point the variance of error is greater.

    Most Engineering firms want as accurate as possible information. This requirement is typically sub-meter, hence, no push for the locators to be attempting to gather that information.

    Hopefully I didn't confuse the issue.

    mke
    Ummm...two things, there is no accuracy difference between military GPS and Civilian GPS, the signal degradation feature called "Selective Availability" (SA) was discontinued in 2000...both Military and civilian GPS units receive the same L1/L2/L5 signal from the satellites, there are two military signals broadcast from L2 and L5 that supply a time and ionosphere correction that improves accuracy for military GPS, however...civilian GPS systems can receive CORS, VRS, DGPS, WAAS, etc that provide a similar correction. Survey grade GPS systems are actually MORE accurate than military GPS, using Real Time Kinematics (RTK) we can get millimeter accuracy. New Gen3 GPS birds will have a new frequency broadcast, the "M" freq...that is really designed to boost reception in poor coverage areas, but can be manipulated to "focus" GPS signals for area concentrated GPS accuracy improvements for Military GPS units...

    Professional GPS units, such as the Trimble Geo X7 are capable of centimeter accuracy (2.54cm or 25.4mm = 1") so 1cm = 0.39" and with post-processing adjustments can be as accurate as 3 to 5 mm...The Geo X7 is capable of receiving Bluetooth transmissions from your locate device. These units are usually velcro'd to the locators shoulder and can provide very accurate positional data, certainly sub-meter or better with post-processing.
    headcipher likes this.

  9. #9
    Mke
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    Default Re: Is anyone using the new Internal GPS abilities in the newer models of locators?

    Quote Originally Posted by GWJ_CAS View Post
    Ummm...two things, there is no accuracy difference between military GPS and Civilian GPS, the signal degradation feature called "Selective Availability" (SA) was discontinued in 2000...both Military and civilian GPS units receive the same L1/L2/L5 signal from the satellites, there are two military signals broadcast from L2 and L5 that supply a time and ionosphere correction that improves accuracy for military GPS, however...civilian GPS systems can receive CORS, VRS, DGPS, WAAS, etc that provide a similar correction. Survey grade GPS systems are actually MORE accurate than military GPS, using Real Time Kinematics (RTK) we can get millimeter accuracy. New Gen3 GPS birds will have a new frequency broadcast, the "M" freq...that is really designed to boost reception in poor coverage areas, but can be manipulated to "focus" GPS signals for area concentrated GPS accuracy improvements for Military GPS units...

    Professional GPS units, such as the Trimble Geo X7 are capable of centimeter accuracy (2.54cm or 25.4mm = 1") so 1cm = 0.39" and with post-processing adjustments can be as accurate as 3 to 5 mm...The Geo X7 is capable of receiving Bluetooth transmissions from your locate device. These units are usually velcro'd to the locators shoulder and can provide very accurate positional data, certainly sub-meter or better with post-processing.
    GWJ,

    You sound like a surveyor... I only have passing knowledge of the intricacies of the survey equipment. I also know what I've been researching for use with our locating equipment. As of right now, it is not cost effective for the results you get with the current "recommended" GPS recievers listed by the manufacturer. You may be able to correct some issues in processing, but when it comes down to it most companies don't want to put out the money for locators to perform this task.

    However, since you show a greater knowledge about this topic then most.... Do you mind if I PM you and ask some questions?

    mke

  10. #10
    Right Wing Conspirator GWJ_CAS's Avatar
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    Default Re: Is anyone using the new Internal GPS abilities in the newer models of locators?

    Quote Originally Posted by Mke View Post
    GWJ,

    You sound like a surveyor... I only have passing knowledge of the intricacies of the survey equipment. I also know what I've been researching for use with our locating equipment. As of right now, it is not cost effective for the results you get with the current "recommended" GPS recievers listed by the manufacturer. You may be able to correct some issues in processing, but when it comes down to it most companies don't want to put out the money for locators to perform this task.

    However, since you show a greater knowledge about this topic then most.... Do you mind if I PM you and ask some questions?

    mke
    Well MKE, yes...besides the degree in Surveying & Mapping from Oklahoma State University, I work for the largest survey firm in the USA (POB ranked #2 Global Geospatial firm, ENR ranked #93 of the Top 500 Global Design Firms), so yes I am a surveyor but I also have an Engineering degree (from a little "U" in Miami) and I specialize in Subsurface Utility Engineering. If I cannot answer your question, I have 750 other staff members that may be able to...

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