1. Spectrum Considerations for GOES / GOES-R DCS
David G. Lubar
GOES-R Program Office/ PSE-Spectrum Management
The Aerospace Corporation
May 4, 2016
Prepared for the STIWG – Intended for Government and Support Contractors Only
Not for Unlimited Release

2. Background
Radio spectrum has become a popular commodity essential to the masses to power smartphones, tablets, and wireless devices.
As demand increases for download of video and more bandwidth-intensive applications, the commercial broadband industry looks for more and more spectrum resources
And the predominant source of electromagnetic spectrum is the Federal government, according to the calls for repurposing of Federal bandwidth by prospective purchasers.
When and how this this effort take hold and what does it have to do with the Data Collection System users?

3. Presidential Memorandum’s On Spectrum Repurposing or Sharing
Repurposing received significant momentum in 2010 and a stated goal for 500 MHz of
spectrum available by 2020 from the President’s first memorandum:
First Memorandum Highlights
500 MHz in 10 years by vacating or sharing
Provides a timetable and process
Selection of candidate Federal bands
Calls for an annual update report
Further specific action focused on spectrum sharing was directed
in a second memorandum in 2013:
Second Memorandum Highlights
Spectrum Sharing versus Relocation
Creation of a Spectrum Policy Team
Quantative assessments

4. 1675-1695 MHz Meteorological Use Current Use or Planned
GOES-
NOP
AWS-3
Broadband
GOES-RSTU
L-band downlink spectrum is shown on the current (GOES NOP) and future generations (GOES-R S T & U) of the nation’s geostationary weather satellites.
Major links are shown, with items in “blue” indicative of NOAA L-band broadcast downlinks in this band.
Also shown are the handset to tower services just sold in the AWS-3 auction and the tower-to-handset services in spectrum leased by Ligado Networks in MHz and the red outlined spectrum has been requested for sharing for future sale or auction to Ligado.
Broadband
AWS-3

5. Spectrum Sharing Proposal
As many of you know, a commercial company has requested that MHz spectrum be shared with their proposed terrestrial transmitters for smartphones and tablets.
In the GOES-R era, DCPR downlinks into DRGS receivers operate in MHz.
The LTE signal would overlap DCPR, although the top end of the LTE signal includes a “guard band” for isolation with an adjacent LTE signal.
Significant radio frequency interference is possible with a DCS receiving system within the US & P, if this occurs.

6. How Does This Proposed Sharing Impact DCS?
A terrestrial company has petitioned the FCC to consider sharing MHz with the current NOAA meteorological satellite downlink usage
As NTIA and the various Federal groups select candidate spectrum bands to recommend for sharing with commercial users, it is possible that MHz could be included as a candidate.
We will know when the sixth annual update report as stated in the June 2010 Presidential Memorandum is issued by NTIA. That update may be released about the time the STIWG is being conducted, if past year’s report timing are any indication.
Bottom Line: Having strong cellular towers in the same spectrum as DCPR will likely be a significant source of radio frequency interference to the weaker satellite downlink signals sent from GOES-R containing DCP information.
The impact to agencies and their Federal and non-Federal end user beneficiaries of the DCP data must be appreciated and understood by all.

7. DCS Frequencies GOES-NOP and GOES-R
Background
DCS frequencies in the Americas could be subject to interference from proposed or planned systems
DCS Frequencies GOES-NOP and GOES-R
Function
GOES (MHz)
GOES-R (MHz)
DCPR (uplink)
DCPR (downlink)
DCPI / DCPC (uplink)
, ,
DCPC ,
DCPI / DCPC (downlink)
, ,
DCPC ,

8. Spectrum Proposed or Secondary Usage
On-going request by Ligado Networks (formerly LightSquared) to share MHz between NOAA and terrestrial tower transmitters.
FCC Public Notice was issued April 22
Original FCC Proceeding number RM is on the Internet
NTIA is due to issue an updated list of Federal band candidates for sharing in late April or early May.
FCC has granted permission for Spire Global (a commercial remote sensing satellite constellation) to uplink in MHz from domestic earth stations to nine satellites in non-GEO orbit, on a non-interference basis
Initial computations place these signals about the same power level as a DCP into the GOES/GOES-R spacecraft UHF receiver
Quick action by DOC Office of Radio Frequency Management and NESDIS frequency management drove FCC to force 24 hour/day “stop buzzer” contact at Spire to shut down if interference reported

9. FCC Public Notice 1675-1680 MHz FCC Notice issued Friday April 22
Solicitation for users of GOES & GOES-R in MHz band
FCC looking for input on non-federal users that benefit from the data in this spectrum
Need input from current uses and regarding future GOES-R usage
How do non-Federal entities make use of [Federal] products and services ?
Petitioner suggests cloud delivery and alternative methods
Additional requests to comment on studies by the petitioner
Alion reports on NOAA Operations use of GOES and GOES-R
Adequacy of AWS-3 Protection Zones
Potential for anomalous propagation (thermal ducting) for DCPR sites
Can you co exist with 32 dBW tower transmitters?

10. Public Notice Response
Unfortunately, Federal agencies can not directly participate in FCC public comment proceedings
However, an agency can submit a letter via NTIA, (with their concurrence)
State, Local, Tribal and Private users should be encouraged to speak up and file letters in this RM proceeding
Initial comments are due by June 21, 2016
Then commenters are allowed to review and comment on what has already been filed. These review comments are due by July 21, 2016
This spectrum band has a high likelihood to be listed on NTIA’s list of bands to be considered for commercial spectrum sharing – the sixth interim progress report on the President’s Ten Year (Spectrum) Plan is forthcoming from NTIA
This is the hydrological community’s one (and perhaps only) chance to indicate how this information is used, what it contributes to the economy and to public safety.

11. User Input for FCC Public Notice
It will be critical to get end users to provide comment to the forthcoming FCC Public Notice on use of MHz.
FCC desires information on non-Federal use (or on non-Federal users benefiting from Federal use of this spectrum)

12. 1675-1680 MHz spectrum sharing History Noted letters in FCC proceeding
LightSquared first asked for sharing in 2012, as a petition to the FCC in proceeding RM-11681
President’s budget has contained a legislative recommendation to FCC for past 3 or 4 years to auction or make MHz available by fee action for terrestrial use. (Page 11 of FY17 request)
LightSquared renamed Ligado Networks in February 2016
17 congressmen sent letter to FCC urging adaptation of MHz as soon as possible for shared terrestrial use
Noted letters in FCC proceeding
AMS/NWA July 2015
AMS/NWA March 2016
National Hydrologic Warning Council March 2016
World Meteorological Organization
Congressional Letters
National Weather Association March 2016

13. Summary and Action on Spectrum Sharing
In the past we may have sounded like “the sky is falling”, and
little response from affected end beneficiaries of DCS resulted –
although the DCS community loudly voiced it’s concern
Now, “the sky is falling and it’s burning”
This FCC proceeding is the one and only chance to voice concerns to regulators before they decide whether or not to share this spectrum with terrestrial transmitters.
Source wnyc.org
It is important that non-Federal users and beneficiaries
comment in the RM FCC process

14. Small Satellite Constellations in the 401-403 MHz Band as an uplink
The amount of small satellite constellations, either being proposed or being constructed is growing monthly.
For US systems, the FCC often issues either experimental authorizations on a non-interference basis, or a Part 25 license.
Two examples of constellations that have asked to uplink in or near the DCP uplink band:
Spire Global’s LEMUR-2
Astro Digital (Aquila Space) Landmapper constellation/Corvus-BC-3 sat.
System
Frequency (MHz)
LEMUR-2
29 satellites
MHz up
13 US Gnd stations
Non-interference basis authorization
Corvus-BC-3
MHz up
Filing says they avoided DCS freq.

15. Small Satellite Constellations
There are currently a large number of satellite constellations in stages of deployment in US.
Most conform the the US Table of Frequency Allocations that dictates usage and direction of transmission between space and ground antennas.
One commercial remote sensing system requested an exception so they can uplink in the MHz band – Spire Global
Spire Satellite

16. Overview Will the Lemur uplink at 406.525 MHz
GOES-R
Geostationary
Will the Lemur uplink at MHz
overload the GOES-R UHF receiver
front end amplifier, and what might be
the impact of this overload
condition?
MHz
Lemur
LEO
/- 0.2 MHz
Lemur uplink
Data Collection Platforms

17. Conditional Grant by FCC for Spire’s Authorization
Spire was granted authorization for 9 satellites to deploy at altitudes below 435 km either from ISS or from Cygnus cargo capsule.
Spire operations uplink, MHz downlink are on a non-harmful interference basis
They must provide a stop buzzer POC to NESDIS F.M. and to NTIA 24/7/365.
The 9 satellites have a license term of 18 months
LEMUR-2 Satellites
CYGNUS OA-6 docked
On March 26 at the ISS.
9 Lemur satellites are onboard
Understand plan is to launch
these satellites (& 20 Dove
Flock 2e for Planet Labs) after
CYGNUS OA-6 disconnects
from the ISS on May 20 during
it’s 8 day return to Earth and
disposal over the South Pacific
Spire Conditional Grant Dated March 26, 2016

18. Small Satellites & DCS
Cases should be evaluated against the spacecraft receiver properties with DCP signal loading considered
There is no definitive analysis showing that these systems may cause issues in the GOES or GOES-R DCS UHF receiver on orbit
However, if multiple systems are visible at the same time, and if their signal strengths differ considerably, intermodulation products could occur within the spacecraft receiver
Mathematically they may fall outside the domestic DCS band, the cases would require computation and due diligence.

19. Small Satellite Summary
There are many new small satellites planned within the US and international regulatory processes
They feature different degrees of rigor in their spectrum management efforts, and some do uplink in or near the DCPR frequencies in MHz
Recommend that recorded anomalous signal levels from DADDS be reported to NOAA NESDIS Frequency Management, along with date, time and exact channel frequenc(ies). This may be the only way to determine if ground uplinks servicing small satellite constellations are causing interference to DCS operations.
To date no such cases have been reported to FM
These systems, many of which support environmental measurements and remote sensing, useful to NOAA, must not detract from other satellite services due to radio frequency interference.

20. Summary
Demands for spectrum are growing and new systems are being created on an unprecedented basis.
Voicing your needs via an agency spectrum official is now a necessity, not a luxury, and receiving user and non-Federal partner inputs to the FCC is also paramount as they seek to make spectrum sharing or repurposing decisions in support of the broadband wireless community
Silence in the spectrum community is assumed to be consent