Monthly Archives: July 2013

ProMark 500 Tracks SV’s, Gets Corrections, Won’t Hold Fix

A customer sent me a ProMark 500 (purchased from someone else) with the message that I was the last resort.

Complaints: everything appears to work, it tracks US and GLONASS SV’s, it gets corrections and goes to FLOAT. But it sits in FLOAT forever. Every once in a while the PM500 will FIX, but then FLOATs out again.

So I got the receiver, connected it to TURN (The Utah Reference Network) and went to the Monitor Skyplot screen in SurvCE:


I immediately knew what the issue was and snapped the picture above.

Do you know what the problem is?

If you look at the red bars, which indicate tracked US SV’s, you will notice that they only have one bar per SV, it is the L1 bar. There is no L2 bar. (Look at the blue GLONASS bars for comparison.)

This receiver has lost it’s L2 key. Actually, this is fairly common when receivers are updated from version 3 to version 4 software. In previous versions, L2 was activated by default. At some point they (the French Guys) decided that an L1 ProMark 500 might be a good price point to have.

The new software is supposed to AUTOMATICALLY enable L2 on ProMark 500 receivers with date codes prior to some date. But it does not always work.

When this happens, you need to get a dedicated L2 key from your dealer and install it. After doing the install, which will look something like this PASH command:


You need to do a three-fingered-reset to have the receiver automatically enable L2 tracking at the GNSS engine level. (You can alternatively send the receiver another command, but I like to do the three-fingered-reset because it cleans up everything else.)

Because of this, I am in the habit of ALWAYS checking the current options after doing an update.


Filed under Uncategorized

Is a NGS CORS Station Available

Often I get the question, “what is up with CORS station ‘xxxx’. GNSS Solutions no longer will download data!?”

Here is how to find out if data is available from a particular site:

1. Browse to the NGS CORS mother site [ here ]

NGS CORS Page2. Type in the CORS site you are interested in checking out (I am going to look at SGU1):

ngscors2then press “Enter SiteID”

3. When the CORS Information page is displayed:


click on ‘Data Availability’.

4. Hang tight, it will take 15-seconds to display the profile:

DataAvail2Blue bars are good. Gray bars suck.

That is all you need to know!

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Filed under GNSS Solutions, Uncategorized

Nightmare on GIS Street: GNSS Accuracy, Datums and Geospatial Data

What is the difference between a reference frame, a datum and a realization?

Why is timestamping coordinates important?

What is the difference between NAD83 CORS96 and NAD83 2011?

Why don’t ESRI products support these concepts?

If you are like most people, it is all a nasty-ugly blur.

Wouldn’t it be great if someone make a simple video with really smart presenters that started to explain all of this?

Someone (Eric Gakstatter) did! And the video is great! It features Kevin Kelly the Geodesist from ESRI (who would have guessed that they had one?) Craig Greenwald and Michael Dennis from NGS who absolutely knocks it out of the park on this webinar.

This [ link ] should get you the webinar recording. You have until September 18th 2013 to watch it. Do It Now! I can not recommend this webinar highly enough! It is fantastic.

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Filed under Carlson, FAST Survey, GNSS Solutions

A Better Precision Antenna Cable for the PM3, PM100, PM120, MM100, MM120 and PM220

We sell a lot of replacement antenna cables for these GPS receivers:

ProMark 3, MobileMapper CE, MobileMapper CX
ProMark 100, ProMark 120, ProMark 200, ProMark 220
MobileMapper 100, MobileMapper 120

The factory part number is 702058 and the factory cable looks like this:

702058 Precision Antenna Cable

This cable is reasonably priced ($85) and relatively well made, but….

It suffers from some endemic issues:

1. If the heat shrink on the right-angle end fails and the RG-58 coax rotates in the barrel the cable is toast. (This happens a lot.) The connector can not be repaired because the access screw is super-glued in place.

2. If this cable is used on these receivers:

ProMark 100, ProMark 120, ProMark 220
MobileMapper 100, MobileMapper 120

and the connector and cable are rotated 360 degrees, the connector will ALWAYS pull out of the receiver. Always.

S0 we have engineered an alternative cable:

iGage PN IG702058

This cable has a straight connector for the receiver, uses LMR100 microwave coaxial cable and has a braided sheath for cable protection.

This is what it looks like on a pole mounted receiver:

Additional information is available [ here ].

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Filed under MM100 - PM100 - PM200, MMCX, PM3

Internal Batteries in ProMark 3, MobileMapper CX and MobileMapper CE Receivers

If you have ProMark 3, MobileMapper CX or MobileMapper CE receivers…

…sit down, grab a beer and take a deep breath….

We (iGage) believe that the internal battery backup batteries in these receivers are reaching the end-of-life now.

First, it is not the end of the world. We can replace the batteries for $150 for a single receiver or $250 for two receivers. [ Click Here For More Info ]

Okay, take another breath now and I will share the details:

We have gotten complaints that these receivers are taking forever to begin tracking SV’s

We have gotten complaints that these receivers are not detecting the external antenna (see below for additional information)

We have gotten complaints that receivers are loosing the date/time (well actually this has ALWAYS been an issue, but it seems worse now)

I think that the receivers are losing the GPS ephemeris when the main battery is removed from the receiver for more than a minute or two. This has been verified by measuring the voltage on the backup batteries (actually super caps):


The voltage is 3 volts when the batteries are new, on the five receivers that I opened and checked this week, the voltage was 0.4 Volts or less.

We replaced the batteries in a couple of units and sure enough, they track SV’s in a minute or two after having batteries removed for a while.

You can get around the lost ephemeris issue by turning the receivers on 15-minutes before you need to use them and let them acquire SV’s with the internal antenna while you are driving to the job. You can also keep a charged main battery in the receiver and swap them quickly when exchanging.

But there is a danger in not replacing the batteries: they can leak acid which can eat the adjoining traces. Luckily the batteries are not too big, so they don’t leak much.

More on Not Detecting External Antenna

If you are encountering problems with the PM3 or MMCX not detecting the external antenna, remember that the antenna status is not correctly reported until after the receiver tracks enough SV’s to get a position:


So even if an external antenna is plugged in, it will not be reported until AFTER a position is displayed.

If your battery is dead and you have to wait for 5-minutes for the PM3 to track SV’s, then it may appear that the external antenna is faulty. Not so.


Filed under MMCX, PM3, Uncategorized

Factory Service for Ashtech / Spectra Precision / Magellan Professional / Thales Equipment

If you are looking for factory service on MobileMapper and ProMark receivers, the Spectra Precision RMA request is no longer the way to go:


Now the correct way to request repair services is to send a piece of email to:

with the following information:

  • Company Name
  • Contact Name
  • Address
  • Phone Number 
  • email
  • Product Model
  • Serial Number
  • Reason for Repair

You should get a reply with an SWO number and instructions for returning the equipment to the factory repair depot.

Alternatively you can call 888-409-2904 

This is a GREAT improvement, it is nearly impossible to create an account on the Spectra Precision website (which was required to submit the RMA request.)

If you are looking for repairs on legacy equipment (ProMark 3, MMCX, PM2 and the like) checkout [ Legacy Repairs ].

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Filed under Uncategorized