Two Feet Forward

Did you watch Dr. Michael Dennis’s ‘Fate of the US-Survey Foot’ webinar? If not, you should. Here is the link:

As always, Dr. Dennis knocks it out of the park. A Geodetic Rock Star. This webinar should be shown at the beginning of every survey course series and every GIS course taught in the USA.


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The End of Non-Customer Support

Effective Thursday 18 April 2019 I (Mark Silver) will no longer entertain helping non-customers with issues on equipment that iGage Mapping Corporation did not sell. In addition, iGage will no longer sell accessories, batteries, cables, equipment outside of the United States.

The Back-Story

Since March I have fielded as many as 50 email / phone questions per day from non-customers asking about WNRO (Week Number Roll Over) issues. Since the beginning of April I have gotten over 20 questions per day requesting help with installing updated firmware on receivers, post-processing 1999 dated files. Yesterday I was up until 11:30 pm responding to these queries. Of the 20+ questions yesterday only one was from an iGage customer who purchased the equipment in question from iGage.

Some of the questions come from customers who purchased equipment elsewhere, but have purchased a battery or cable from iGage in the past. Purchasing a cable for a ProMark 500 does not entitle you to support for that ProMark 500 receiver. And if the cable worked when you received it 5 years ago, our warranty has expired and we bear no responsibility for supporting you if it appears to not work today.

All of these non-customer questions share a common thread: the equipment/software was purchased from another dealer who is out of business or no longer will provide support for the equipment that they previously sold.

iGage Customers

If you purchased equipment from iGage, I am happy to support that equipment as best I can (keep in mind that most of the questions at hand are about 7+ year  old equipment.) However, I will ONLY support equipment that iGage sold directly or through one of our sub-dealers. So if you purchased multiple receivers from multiple sources, I am not going to help you with the equipment not purchased here.

What if you are willing to pay for support?

Well, that is great, but I will not support equipment that iGage did not sell. I don’t care if you are willing to pay for support.

An alternative is to return the equipment to the original company and purchase replacement equipment from iGage.


Too harsh of  response? Perhaps, but by continuing to spend 8+ hours per day supporting non-customers I am putting the company that I work for at risk of failure. We survive by selling equipment and providing the best support and service that we can. Please consider purchasing equipment from us if you expect us to provide you support and service.


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Magellen Professional, Ashtech, Spectra Precision, Spectra Geospatial GNSS Receivers and GPS Week Number Rollover – April 2019

This is an URGENT NOTICE for users of the following GNSS receivers:

ProFlex 500, ProFlex 800
MobileMapper 100, 120
ProMark 100, 120, 200, 220, 700, 800
SP 20, 60, 80, 90m

The notice also includes information for users of:

ProMark 700
MobileMapper 300
EPOCH 10, 25, 35, 50

If you are using any of these receivers, you MUST update firmware prior to April 6th 2019 or your receivers will stop working at (about) midnight UTC the morning of April 7th 2019.

Specific Instructions, with links to updated firmware can be found in this Official Spectra Geospatial ‘Support Note’:


(The following note is from Mark Silver and does not reflect an official position from the factory.)

No official information is available from the factory regarding ProMark 3, ProMark 2 or earlier receivers. Since the ProMark 100 receiver is a descendant of the ProMark 3 and all subsequent devices (ProMark 120, ProMark 500, ProMark 800 and SP80/60) have mandatory firmware updates it is my guess that the PM2/PM3 receivers will fail on rollover. In addition, I believe that the desktop tool ‘GNSS Solutions’ will probably also fail.

Will the failure be catastrophic? Perhaps not. In the case of static files from ProMark 3 receivers it may be possible to ‘fix’ them using a software shim tool to modify RINEX dates.

To put the ProMark 3 in perspective, I do not believe that we have any working PM3’s at iGage to play with at this point (and the search for them may prompt a needed shelf cleaning and subsequent dumpster fill.) I will disclose that I have received more calls from ProMark 3 users worried about WNRO than any other device. So I do realize that there are many PM3’s in daily use.

I would caution everyone that while some receivers have been tested using GPS/GNSS simulators, the process of constructing simulation files is VERY complicated. Normally the simulators use signals that are recorded and then replayed. So there might be additional complications discovered after April 7th.

In any case, I plan to spend Sunday April 7th pulling old receivers and testing them at the office. Hopefully it will be an uneventful, sunny, spring day.

Good tracking to all,

Mark Silver


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Carlson Formated Argentina IGN GEOID Modelo AR16

He convertido el archivo para usted.

Descargar desde esta ubicación web:

Ambos formatos de Carlson están disponibles, creo que el formato .GSB es superior.

Aquí hay una visualización:


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Another SurvCE Grid to Ground & Localization Resource

Here is a great resource for Grid-to-Ground and Localization in Carlson SurvCE (specifically Version 5.08)

[ SurvCE_LocalizationG2G_Rev014 ]

Index to the PDF:

Localization & Grid to Ground Scale Factors in SurvCE. 1

Grid-to-Ground. 1

Localizations. 1

Reusing last localization? Clean slate!. 1

001 Start a new job at 10,000, 10,000; use Geodetic North at Ground based at a chosen parcel corner. 2

002 Stat a new job, following a historic plat, matching the original basis-of-bearing but holding exact ground measurements. 5

003 Start a new job, using a custom Low Distortion Projection, based at a central location at the job. Choose the correct projection scale factor so that distances are ground. 6

004 Using the previous job, with LDP geodetic basis of bearings and ground distances (10,000, 10,000.) Hand enter a couple of NGS Control Points using the published geodetic positions. 10

005 Start a new job, retracing an existing survey. Initially use a few points to ‘get on the system’ then after finding the remaining corners, do a multipoint calibration looking for blunders. 11

006 Mix total station shots with GPS measurements at Grid. 14

007 Choose an appropriate Combined Scale Factor based on Job corners. Set a Geodetic (True North) BOB system at the job center. (Tricky because you need raw data at Job Center.). 16

008 Network Leveraging of Localization. 19

01:: I just collected 1,200 GPS field shots in the wrong state plane zone!. 27

02:: I just collected a ton of GPS data in international feet, it should have been US Survey Feet!. 28

03:: I collected a day’s worth of data using an autonomous base position, I would like to convert it to a true base position. 29

Adjusting Data Stored with an Autonomous Base to an OPUS Position. 29

03B:: How to read a GNSS Raw File. 35

GNSS Base. 35

.REF File Description. 36

.RW5 Base File Description. 37

04:: I did not store the base position as a point when I did a ‘Read GPS’, can I extract the base position from the raw file (.RW5) or the ref file (.ref)?. 38

05:: I localized on two points at this job and stored a ton of existing features. Now I realize that one of my control points was actually an offset. How do I save my work?. 38

06:: I just stored a shot with a 40000 foot HI!  39

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SP80: High HSDV (HRMS)

Recently (June 18th 2018) I began to hear complaints of high HSDV (same as HRMS) from multiple SP80 customers. Initial complains pointed to a ‘change in the afternoon’ after having no issues in the morning.

I believe that this behavior may attributable to US GPS SV 25 being in the used constellation on the BASE.

If you are having issues with high HSDV the safest thing may be to just turn off SV G25. I would turn off SV G25 on both the base and the rover.

Mission Planning

First off, you may want to check when SV25 will be available at your location. I like the new Trimble / Spectra Precision Mission Planning tool which now works without loading Silverlight (I think it works on all browsers now).

Here is a direct link: [ SP Mission Planning ].

Be sure you get the Position, Time-Zone and Date correct. Once you do, you can use the ‘Visibility’ graph to figure out when SV25 will be available:


Be sure to get the time zone correct or the displayed local times will be incorrect.

SurvCE / FAST Survey with the SP80

In SurvCE / FAST Survey you can disable G25 by waiting until SV25 is ‘seen’ by the receiver and then navigate to ‘Monitor/Skyplot’ and select the ‘SATInfo’ tab. Click on G25:


and UNCHECK ‘Satellite Enabled’.

SurveyPro with the SP80

Go to the ‘GNSS Status’ screen. You can get to this screen by clicking on the satellite icon on most survey screens:


The GNSS Status screen is shown, select ‘Sat Info’ and ‘Show All’:


now click and hold on the G25 box for three seconds:


Click on ‘Disable G25’.

PASHS Command

You can manually turn off the satellite with this PASH command:


Feedback Appreciated

I am not positive that this is the issue and I don’t know for sure that the procedures work. Please let me know if you can verify (or not) and I will update this post.

Good surveying to you!

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OPUS: Best Practices

I finished the first revision of my epic term paper! Well, actually it is probably the 6th revision at this point, but close enough.

Lots of people contributed lots of examples (and I am still excited to accept more case studies).

So, if you are a new OPUS user (RS, Static or Projects) and you are wondering why your jobs fail; or you just want some light reading; check this out: [ OPUS Best Practices ].

Some of the big take-aways:

  • 25% of OPUS-RS jobs fail
  • The diameter of the Fresnel zone for GPS L1
  • Why OPUS fails where RTK rocks
  • Occupying past midnight UTC is asking for trouble

Again, if you have additional contributions, send them to me!

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