Considerations for Testing GLONASS Ken Bays, PLS

Lead Geodetic Surveyor, Oregon DOT2014 ODOT Surveyors Conference

1 April 2014

Mount Hood, OregonPhoto by Daryl Moistnerwww.nevadasurveyor.com

Overview Why test GLONASS? What do we want to test? Who is involved in the testing? Issues with GLONASS Planning for testing Issues with testing

What does the acronym GPS stand for?– Global Positioning System– Generally accepted as the name for U.S.

GNSS system What does the acronym GNSS stand

for?– Global Navigation Satellite System– Generic term for the satellite navigation

system of any nation.

What is the more specific acronym for the US GPS system?– NAVSTAR

What does NAVSTAR stand for?– NAVigation Satellite Timing And Ranging

What does GLONASS mean:

– Global'naya Навигатсайонная Спутниковая Система =

– Global'naya Navigatsionnaya Sputnikovaya Sistema =

– Global Orbiting Navigation Satellite System

Why test GLONASS Evaluate when Oregon DOT surveyors

should or should not use GLONASS Should we add GLONASS capability to the

Oregon Real-time GPS Network? Benefit to surveyors to know more about

the solutions they are using. Varying manufacturer claims Lots of anecdotal claims and “back-of-the-

envelope” tests out there

What do we want to test

Testing Productivity– Does it always help to add GLONASS?– Will GLONASS always enable a solution

in heavy canopy when GPS-only won’t yield a solution?

What do we want to test

Testing Accuracy– Is accuracy the same, worse, or better than GPS-only in

open and closed canopy. Some older papers suggest GLONASS degrades

accuracy of GPS-only solutions– But remember the GLONASS constellation was

down to 6 or 7 satellites a few years ago. Leica GS14 datasheet claims “GPS and GLONASS can

increase performance AND accuracy by up to 30% relative to GPS only”.

– Is the claimed accuracy increase the same in and out of canopy?

Other papers report little accuracy difference when adding GLONASS to GPS-only.

Who is involved in the testing? Geometronics Unit, Oregon DOT

– Operating the Oregon Real-time GPS Network Oregon State University

– Dan Gillins, Assistant Professor, PhD, PLS Submitted abstract to ION for GNSS+ 2014

Conference– Michael Eddy: graduate thesis

Processing long static baselines w/ and w/o GLONASS

32 NAVSTAR 24 GLONASS

4 Galileo 15 BeiDou

Issues with GLONASS Time tags and receiver clock offsets: GPS

time vs GLONASS time Reference datum offsets from GPS (WGS84) to GLONASS (PZ-90.02) GLONASS FDMA format vs the CDMA

format for GPS and Galileo New Russian K satellites will be CDMA

– Different manufacturers have different, usually proprietary, solutions for handling these biases

Issues with GLONASS Very limited GLONASS tracking/monitoring network worldwide; mostly

within Russia– Russia plans to add world wide tracking stations– Current political situation could inhibit GPS/Galileo cooperation with

GLONASS 2013 State Dept. negotiations to establish GLONASS monitor

station in US already blocked by Congress. No GLONASS plan for new signal in L5 Band

– L5 is a Safey-of-Life protected frequency– L5 is supported by GPS, Galileo and Beidou

Management & corruption issues– 2010: Dismissal of two high-ranking space officials– 2010: Resignation of head of Russian Space Agency (Roscosmos)

After the first launch failure of 3 GLONASS SVs– 2012: Designer for GLONASS sacked: $17 million embezzlement

siphoned GLONASS R & D funds with fake orders/phony companies– 2013: Investigation of $12 million embezzlement

M2M Telematics, part of Russian GLONASS system

Russian GLONASS/GNSS Forum’s Questionairre http://aggf.ru/pr.php?nn=5375

“4. Является ли важным с точки зрения конкурентоспособности, чтобы КА системы ГЛОНАСС, в дополнение к запланированным новым кодовым сигналам в традиционных диапазонах ГЛОНАСС (L1, L2, L3) передавали бы еще и сигнал в диапазоне L5? Почему? Если да, то для каких потребителей это важно?”

As reported on-line by in GPS World magazine:http://gpsworld.com/survey-seeks-suggestions-on-future-of-glonass

Russian GLONASS/GNSS Forum’s Questionairre http://aggf.ru/pr.php?nn=5375

“4. Is it important in terms of competitiveness, for the GLONASS satellites, in addition to the planned new code signals in the traditional GLONASS bands (L1, L2, L3) to add another signal in the range L5? Why? If yes, for which consumers is this important?”

As reported on-line by in GPS World magazine:http://gpsworld.com/survey-seeks-suggestions-on-future-of-glonass

and translated by Richard Langley, Innovations Editor for GPS World:

Issues with GLONASS

Availability of real-time precise ephemerides for GLONASS?

Oregon Real-time GPS Network software automatically downloads the predicted half of the Ultra-Rapid ephemerides four times daily and incorporates them into our network (multi-base) real-time correctors.

Will real-time precise GLONASS ephemerides be available for RTNs ???

IGS MGEX (Multi GNSS Experiment)http://igs.org/mgex/

The Multi-GNSS Experiment (MGEX) has been set-up by the International GNSS Service (IGS) to track, collate and analyze all available GNSS signals. This includes signals from the BeiDou, Galileo and QZSS systems, as well as from modernized GPS and GLONASS satellites and any space-based augmentation system (SBAS) of interest.

Analysis centers will attempt to estimate inter-system calibration biases, compare equipment performance and further develop processing software capable of handling multiple GNSS observation data.

The development of multi-GNSS IGS products.

Planning for testing Letters to manufacturers

– How do their products use GLONASS in RTK and postprocessing.

– Supplemental to GPS or equal to GPS Investigate prior research

– White papers– ION GNSS presentation archives– E-mail: Dan Gillins, OSU, to Dr Neil

Weston, Deputy Director, NGS

E-mail: Dr Neil Weston, Deputy Director, NGS,to Dan Gillins, OSU

– NGS has not done too much with respect to GPS +GLONASS processing

– NGS has spent a few months looking at the Pages software (NGS) to see how GLONASS can be incorporated

– NGS hopes to add GLONASS (to their products such

as OPUS) and also focus on Galileo– With respect to helping out with a study, NGS

cannot offer too much other than CORS data with GPS+GLONASS.  

– Do you have more specific ideas in mind?

NGS testing and evaluation of GLONASS would help real-time network administrators and also surveyors in general

Planning for Testing Perform enough test repetitions to yield

statistically valid results. Publish accuracy analysis at the 95%

confidence level per FGDC Geospatial Positioning Accuracy Standards.– http://www.fgdc.gov/standards/projects/FGDC-standards-projects/accuracy/   

Planning for testingTesting in open, medium, and heavy canopy.

Establish accurate test networks in canopy with total station network tied to accurate static GPS sites in open canopy.

US Forest Service Clackamas GPS Test NetworkMt. Hood National Forest

US Forest Service Clackamas GPS Test NetworkMt. Hood National Forest

Issues with testing Testing can’t cover all brands of GPS receivers Different GPS RTN softwares handle GLONASS differently As GNSS constellations change, ongoing testing will be

needed– GPS new CNAV Signals, ie. L5 stronger signal strength is supposed to

help in canopy.– GLONASS: CDMA?, L5?, worldwide tracking/monitoring?– BEIDOU: coming on strong ?– Galileo: just around the corner ??????

Manufacturers will adopt new and better processing algorithms to better take advantage of various GNSS

All these changes will point out the need for ongoing testing.– Test networks with accurately positioned marks will continue to be

valuable.

Oregon Real-time GPS Networkwww.TheORGN.net

ORGN@odot.state.or.usThe beach at Bandon, Oregon

Did you get a fix on four Galileo satellites? Then there could be a certificate in it for you! ESA will recognize Galileo pioneers with commemorative certificates to the first 50 entities who document their achievement of a past or present fix. Details of how to apply are provided here.

To mark the first anniversary of Galileo’s historic first satnav positioning measurement, ESA plans to award certificates to groups who picked up signals from the four satellites in orbit to perform their own fixes.

http://gpsworld.com/get-a-galileo-position-fix-esa-wants-to-give-you-a-prize

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