A New Standard for L1/L2 GPS Static Receivers?

June 13, 2013  - By

In the more than 100+ articles I’ve written for GPS World magazine over the past seven years, I don’t think I’ve ever written about a new product introduction like you will see below. I tend to focus on GNSS and geospatial technologies rather than a brand-specific products and services. In fact, last week I had an outline prepared for my article that included some really cool free and useful GPS/GNSS apps. I decided to set that outline aside until later, in favor of writing about this product.

Although certainly different than mainstream GPS/GNSS receivers, I wouldn’t refer to this new product as a disruptive one (a marketing term used to describe something that is industry-changing) and it doesn’t incorporate leading-edge GPS/GNSS technology. In fact, it’s relatively low-tech in comparison to the other GPS/GNSS surveying receivers available in the marketplace.

Even more fascinating is the fact that the product was developed not by any of the mainstream GPS/GNSS receiver manufacturers you hear about today, but rather an electrical engineer from Utah who leveraged the design/manufacturing expertise of one of China’s largest manufacturers of GPS/GNSS surveying receivers.

The final nail in the coffin is the fact that I’ve expended thousands of words in GPS World denouncing the future of post-processing and celebrating the virtues of high-precision, real-time GNSS (RTK, SBAS, PPP) receivers.

I tried to talk myself out of writing this article more than once, telling myself that I’ve never written specifically about a new product and I wasn’t going to start now. But, as much as I didn’t want to, I always came back because it is so darned compelling.

While the product is not aligned with my vision of real-time being the future of high-precision GNSS receivers, it is perfectly aligned with my vision that the cost of high-precision GNSS receivers are dropping and will continue to decline considerably over the next few years.

The product is the X90-OPUS GPS receiver.

It does not use leading-edge GPS technology.

It’s not sexy.

It’s not perfect.

However…it is incredibly inexpensive, and it is designed to be perfectly simple to operate.


iGage X90-OPUS Photo: iGage

In one sentence, the X90-OPUS is a one-button, dual-frequency GPS receiver that is specifically designed to use the National Geodetic Survey’s free online OPUS post-processing service to achieve centimeter-level GPS positioning anywhere in the United States and surrounding countries.

You might say to yourself, “So what? There are plenty of GPS receivers on the market that are capable of providing this functionality.” I would make the same comment, except it has one product feature that I’ve never seen before.

The Price

What makes the X90-OPUS so compelling is its low cost. The X90-OPUS GPS receiver sells for US$2,450, including all software and accessories (except for tripod/tribrach) that allow you to submit GPS data files to OPUS in a very automated fashion.

At US$2,450, the X90-OPUS may open a new world for surveyors, engineers, and scientists who have previously shunned high-precision GPS receivers due to their high cost and complexity.


For those of you who yearn for the yesteryear of the one-button Ashtech’s legacy Locus GPS receiver, the X90-OPUS reminds me of that sort of simplicity, but on steroids. The X90-OPUS is a dual-frequency (L1/L2) receiver, while the Locus was a single-frequency receiver. The difference is that one can use OPUS and the other cannot. OPUS post-processing doesn’t support single-frequency GPS receivers. However, Mark Silver, the electrical engineer from Utah, has taken it a step further by developing software that automates the OPUS data submission process. Although I’ve made it clear in the past that I’m not a fan of post-processing, it doesn’t get any easier than this. You don’t need to buy a base station, and you don’t need to own post-processing software. It’s a two-button push operation: once to turn it on, and once to turn it off.


X90-OPUS Software Photo: iGage

The X90-OPUS receiver was characterized by the National Geodetic Survey back in March 2013 and is listed on the NGS’s Individual Antenna Calibration website.


Photo: iGage


Photo: iGage

Pertinent Background

You might think that with the US$2,450 price point and not being offered by a major GPS receiver manufacturer, this is some home-brew GPS receiver. If you thought that, you would be incorrect. The GPS engine in the X90-OPUS is a Pacific Crest BD950, the same engine found in many receivers from other GNSS system manufacturers. CHCNav integrated the GPS engine into its casing to produce the X90 receiver. However, Mark added his own special sauce to the X90 to turn it into the X90-OPUS so this isn’t just a CHCNav receiver being marketed by iGage (Mark’s company).

In all fairness, I’ve not touched the X90-OPUS yet. I likely will in the next few days. However, unless the hardware is unreliable, I don’t see how this product is not going to be a winner, and it will introduce high-precision GPS receivers to an entirely new group of surveyors, engineers and scientists who have been holding out on using GPS.

Webinar This Thursday

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

Date: Thursday, June 20, 2013
Time: 10 a.m. PDT / 1 p.m. EDT / 6 p.m. GMT

Summary: A look at the challenge of dealing with horizontal datums in your GIS. We are moving into a new era in dealing with datum transformations. Geodata 2.0 is coming, and it can create big headaches when attempting to combine disparate geospatial databases. Sensors such as GPS receivers, remote sensing imagery, and 3D scanning provide much more accurate data, setting up a collision with outdated and mismatched legacy horizontal datums.


Kevin_M_Kelly_headshotKevin Kelly, Geodesist, ESRI, Inc.
Kevin Kelly is a Geodesist with ESRI in Redlands, California where he researches and implements geodetic algorithms and applications for the ArcGIS software. His experience spans over 35 years in hydrography, geodesy, surveying and most recently, geographic information systems. He has held the posts of Manager of Geodetic Services for the Province of Ontario, Chief Geodesist for the Kingdom of Saudi Arabia’s Military Survey Department and Senior Project Surveyor for The Keith Companies (now Stantec, Inc.). Mr. Kelly received a Master of Applied Science in Geodesy at the University of Toronto, Canada and holds an Honors Diploma in Hydrographic Surveying Technology from Humber College in Toronto. He is also a licensed Geodetic Surveyor in the Province of Ontario, Canada.
Craig Greenwald

Craig Greenwald, Technical Director, GeoMobile Innovations
Craig Greenwald is the Technical Director and a principal at GeoMobile Innovations Inc. He has worked in the GPS and Mobile GIS industry for over 13 years, including seven years for GIS software leader, ESRI and is well known for his work on the ESRI ArcPad team. Craig leads the GeoMobile software development and consulting team specializing in Mobile GIS and field data collection applications and technology providing Mobile GIS software, consulting, and training services to GeoMobile Innovations? clients. Craig has real world experience designing, implementing, and consulting on all sizes of projects, ranging from local campground trash mapping to the U.S. national census, and has been a key developer in GeoMobile?s commercial applications such as LaserGIS for ArcPad and Geo-Photo Inventory Tool for Garmin GPS solutions.

Michael L. DennisMichael L. Dennis, RLS, PE, Geodesist, NOAA
Michael L. Dennis, RLS, PE, is a geodesist at NOAA’s National Geodetic Survey (NGS) where his duties include analysis of geometric (“horizontal”) and vertical datums; evaluation of data processing and survey network adjustment procedures; development and promotion of standards and guidelines; integration of NGS products and services with GIS; and public outreach. Mr. Dennis is also a registered professional engineer and surveyor with private sector experience, including ownership of a consulting and surveying firm. Mr. Dennis is an officer of the American Association for Geodetic Surveying (AAGS), an American Congress on Surveying and Mapping (ACSM) Fellow, and a member of the Arizona Professional Land Surveyors Association and the Geomatics Division of the American Society of Civil Engineers.


Eric GakstatterEric Gakstatter, Editor of Geospatial Solutions Monthly and Survey Scene
Eric Gakstatter has been involved in the GPS/GNSS industry for more than 20 years. For 10 years, he held several product management positions in the GPS/GNSS industry, managing the development of several medium- and high-precision GNSS products along with associated data-collection and post-processing software.


Thanks and see you next time.

Follow me on Twitter @ https://twitter.com/GPSGIS_Eric

This article is tagged with , , and posted in Opinions, Survey

About the Author: Eric Gakstatter

Eric Gakstatter has been involved in the GPS/GNSS industry for more than 20 years. For 10 years, he held several product management positions in the GPS/GNSS industry, managing the development of several medium- and high-precision GNSS products along with associated data-collection and post-processing software. Since 2000, he's been a power user of GPS/GNSS technology as well as consulted with capital management companies; federal, state and local government agencies; and private companies on the application and/or development of GPS technology. Since 2006, he's been a contributor to GPS World magazine, serving as editor of the monthly Survey Scene newsletter until 2015, and as editor of Geospatial Solutions monthly newsletter for GPS World's sister site Geospatial Solutions, which focuses on GIS and geospatial technologies.

3 Comments on "A New Standard for L1/L2 GPS Static Receivers?"

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  1. toni says:

    please can this x90 opus perform rtk functions? if yes how?

    • Mark Silver says:

      Hi Toni,

      The X90-OPUS is US satellite only, it does not have Bluetooth, it does not have an internal UHF radio. So it probably is not an appropriate receiver for RTK use.

      Having said that, the internal board is RTK enabled.

      The ‘problem’ is there is only one serial port. So if the X90-OPUS was used as a rover, the serial port would be tied up providing corrections to the head. Without Bluetooth, there is no place to connect a data collector.

      If the X90-OPUS is used as a base, the serial port is tied up with the broadcast radio, and there is no place to connect a data collector to initialize the receiver.

      The one (technically) possible use would be in the ‘Auto-Base’ mode. In this mode, the X90-OPUS can be set to automatically commence broadcasting corrections out the serial port, at a defined rate, when it is turned on using an Autonomously derived position.

      A much better solution would be to purchase an X91+ or X900+ receiver which fully supports simultaneous communication by Bluetooth, Serial Port and GSM Modem. In addition these receivers support GLONASS and other GNSS constellations.

      Finally, if you only need US Satellites, you could purchase a ‘Standard’ X90 receiver. They are more expensive (approaching the cost of the X900+ receiver) because they include both a Bluetooth and GSM Modem.

      In addition to the X90-OPUS; X90’s have been introduced in several variants. Here are the possibilities: Bluetooth or No Bluetooth; UHF Radio or no UHF Radio; Cell Data Modem (three models) or no Cell Data Modem; 32 Megabyte flash or 4 GB flash; USB Flash drive interface or RS232 Serial Interface; GPS or GNSS; “+” or no “+’.

      Suffice it to say that the X90-OPUS is a stripped down X90; just what you need for NGS OPUS-Static, OPUS-RS, OPUS-Projects and other L1/L2 based PPP solutions. Unfortunately not much more.


  2. Mhardie Olario says:

    Good Day Mr Mark Silver, I would like to thank you for all the information regarding to those CHC GNSS products that you’ve mentioned, and we agreed of that. We are also a user of those receivers in the Philippines.:)