SDA-SN-23-0001 (PNT Service Payload RFI).pdf

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Space Development Agency

Tranche 2 PNT Service Payload

Request for Information

SDA-SN-23-0001

The Space Development Agency (SDA) is interested in proliferating a low-cost L-band Position, Navigation and Timing (PNT) service as a payload on the SDA Tranche 2 Transport Layer. The PNT payload would include an on-orbit reprogrammable PNT signal generator, mid-size High Powered Amplifier (HPA), and associated fixed wide beamwidth antenna. The goal is to proliferate this low-cost payload onto hundreds of satellites within future SDA Tranches – potentially as early as Tranche 2. Ideally, solutions will be highly informed by the Tranche 1 Transport Layer and share technical approaches and hardware where possible as size, weight, power, cost (SWAP-C), technical readiness and manufacturability will be significant constraints. The following content provides a notional technical concept of this PNT service, and respondents are welcome to offer alternative hardware and/or software approaches and any perceived risks associated with these concepts. All responses received to this Request for Information (RFI) are solely for information and planning purposes. Responses to this RFI may be used to support future solicitations.

BACKGROUND

SDA is responsible for defining and monitoring the nation’s future threat-driven space architecture, thereby accelerating the development and fielding of new military space capabilities necessary to ensure US technological and military advantage in space for national defense. To achieve this mission, SDA will unify and integrate next-generation space capabilities to deliver the National Defense Space Architecture (NDSA): a resilient military sensing and data transport capability via a proliferated space architecture primarily in Low Earth Orbit (LEO). SDA will not necessarily develop and field all capabilities of the NDSA, but rather orchestrate those efforts across DoD and fill in gaps in capabilities while providing the integrated architecture. The initial “tranches” of the NDSA are predicated on the availability of a ubiquitous data and communications transport provided by relatively small, mass-produced satellites and tactically-relevant payload hardware and software.

Consistent with the continued evolution of the NDSA capabilities, the DoD and US Combatant Commands have identified the SDA proliferated LEO constellation as a potential source for the transmission of a PNT service that would complement, augment, and, in extreme circumstance, back-up to GPS. In this way, the SDA PNT service could serve as a forward-looking capability within NAVWAR resilience planning and operations. Implementation of the SDA PNT service would be compatible with military service planned software-defined PNT receiver user equipment programs (SDUE) and, potentially, as a software upgrade to the Modernized GPS User Equipment (MGUE) Increment 2 program.

REQUEST FOR INFORMATION

The specific frequency bands of interest for the SDA PNT service are the two GPS primary frequencies, L1 (1575.42 +/- 12.276 MHz) and L2 (1227.6 MHz +/- 12.276 MHz). Strong filters

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(either low-loss analog or digital) should be considered. These filters should limit out of band emissions needed to meet ITU spectral requirements and limit interference with nearby Radio Astronomy bands.

The transmit antenna under consideration would include an approximately +/- 60-degree fixed beam width, supporting traditional GPS receiver user antennas with right-hand circular polarization reception. To minimize overall power consumption, SDA estimates that some amount of antenna gain will be necessary to achieve a transmit gain at 10 degrees of the user elevation angle (assuming 1000 km LEO orbits). This is needed to compensate for the approximately 9 db of free space path loss difference between zenith and 10-degree user elevation angle. The following figure shows a notional ideal transmit (Tx) antenna pattern for the PNT service payload.

A steerable beam L-band phased array antenna would be a potential alternative, but, again, SWAP-C is a major concern, thus the focus on simple low-cost fixed antenna array. SDA is nonetheless interested in phased array antennas as options, and accepts information on near term availability, cost and performance.

A mid-sized HPA that covers these two L-band frequencies with expected transmitted power between 10 to 20 watts (assumed better than 50 percent efficiency) to achieve a minimum received power of -158.5 dBW/m2 at a 10-degree elevation angle. SDA expects a high-TRL solution with preference for COTS devices with space pedigree - inferring manufacturing cost reduction through volume and availability. This system may require two separate amplifiers and associated diplexer; SDA is interested both in the single wideband HPA and the two-amplifier approach.

The low-cost SDA on-orbit reprogrammable PNT signal generator should also minimize SWAP-C, likely utilizing either an SDR or FPGA. Signal quality and low phase noise are important signal attributes, as is controlling the harmonic and spectral content. SDA is pursuing signal quality characteristics comparable to IS-GPS-200 specifications. The satellite bus is expected to provide a precise clock and 1 PPS timing reference, and all generated signals need to be traceable to these satellite references to within one nanosecond threshold and 100 picosecond objective.

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Listed below is an outline of a default set of signals, but SDA desires a solution that allows the flexibility to load new signals post launch (on-orbit reprogrammability).

• BPSK(n), where n = 1, 2 or 4 MHz and the chipping rate is n * 1.023 MHz.

• These BPSK signals will operate at any center frequency offset from the GPS L1 and/or L2 center frequency in 1.023 MHz steps, within the +/- 12.276 MHz band width.

• The BPSK could be modulated with a square wave to create a BOC signal.

SDA requires a default short code to support test modes, but operationally will utilize a long code signal that is cryptographically generated. A simple software PRN code generator would be based on publicly available encryption algorithms that might include AES 256/128, Simon, or Speck. The supporting key would be transmitted to the satellite and would be valid for at least three days; a new key would be uploaded prior to expiration of previous key material. Switch-over needs to be seamless to the users. Supporting cryptographic algorithms, operating at slower than TRANSEC speeds, might include SHA256, Key Derivation Functions such as CMAC in CTR mode – as in appendix B of NIST SP 800-108r1 (a configured AES256 CMAC).

Additionally, public key signature methods based on elliptic curves should be supported with a path towards replacing those algorithms as post-quantum signature algorithms mature. The SV should be able to derive short-term keys of durations of 1 day, 1 hour, 10 min, and 6 sec using a NIST key derivation function.

These signals may be modulated with data, either 50, 100 or 200 bps. This modulation could be with or without a pilot channel and the ability to vary the ratio of data and pilot channels. This data would be supplied from the satellite and be described in a future ICD. This data would include orbit and clock of specific satellite information, constellation almanac, signal integrity, and potentially other information.

Recognizing satellite power limitations, SDA will consider CONOPs where the PNT service transmit capability is limited to a single area of regard per orbit to minimize power consumption.

SDA will also consider CONOPs limited to individual transmission of either RF communications (i.e. Link 16) or PNT service but prefers simultaneous transmission if possible.

As a stretch goal, respondents are encouraged to identify if this system can perform the PNT Situational Awareness (Terrestrial GPS Interference Monitoring) requirements when the transmitter is not in use. The PNT SA payload capabilities are given in the SDA’s T1TL solicitation (see www.sda.mil).

SDA asks respondents to provide a technical description of their PNT service payload solution, CONOPs, and an estimate of the SWAP-C requirements for its components and their availability within a two-year delivery cycle. Responses may address any or all of the three major technical areas:

(1) Technical Areas

a. On-orbit reprogrammable PNT signal generator

b. Mid-size HPA

c. L-Band antenna

(2) Ability to meet a two-year delivery with milestone schedule http://www.sda.mil/

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(3) Cost ROM

(4) Risks and opportunities associated with this concept

Risks and opportunities should include both technical (e.g., sufficiency of high-TRL solution to incorporate navigation signal) and administrative or policy concerns (e.g., potential need to recertify the high-TRL solution).

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SUBMISSION INSTRUCTIONS AND CONTACT INFORMATION

Responses to this notice shall include the following information:

• Vendor’s Company Name, Address, and Contact Information.

• Company Capability Statement/Overview (not to exceed one page)

Responses are limited to no more than 5 pages and shall use a minimum of 12-point font and one-inch margins. Responses must be in pdf format and not exceed 20MB. Respondents are welcome to provide commercial product fact sheets – not to exceed four pages each and 40 pages in total – which will not be counted against the stated page limit.

All responses to this RFI must be received no later than 1700 (Eastern) on 21 Nov. 2022.

Unclassified responses shall be sent to osd.pentagon.rsrcmgmt.list.sda-sn-23-0001@mail.mil.

Confidential and Secret information should be emailed to OSD.SDA.Proposals@mail.smil.mil.

Top Secret Information should be emailed to SDA.Proposals@osdj.ic.gov. Respondents submitting classified information must send an unclassified email to osd.pentagon.rsrcmgmt.list.sda-sn-23-0001@mail.mil notifying SDA of this submission method no later than 1700 (Eastern) on 21 Nov. 2022.

When submitting a response, please use the subject “SDA T2 PNT service Payload RFI Response – [Vendor Name]”. Any responses submitted through different channels or to a different e-mail address will not be considered. All submissions may request read receipts, and thus be provided. SDA will review the RFI responses to assess value and potential performance capability.

DISCLAIMERS AND IMPORTANT NOTES

This announcement contains all information required to submit a response. No additional forms, kits, or other materials are needed. Although the word “proposal” is used in this RFI, your response will be treated solely for information and planning purposes; it does not constitute a formal solicitation for proposals. In accordance with FAR 15.201(e), responses to this notice are not offers and cannot be accepted by the Government to form a binding contract. Submission of a response is strictly voluntary and is not required to propose to a subsequent SDA solicitation. No solicitation exists; therefore, do not request a copy of the solicitation. If a solicitation is released, it will be synopsized on SAM.gov. It is the responsibility of any potential offerors/bidders to monitor this site for release of any solicitation or synopsis.

SDA will NOT provide reimbursement for costs incurred in responding to this RFI or participating in any subsequent workshop, briefing, Industry Day or other virtual or in-person discussion, or pay for the information solicited except as an allowable cost under other contracts as provided in subsection 31.205-18, Bid and Proposal Costs, of the Federal Acquisition Regulation.

To the maximum extent possible, please submit non-proprietary information. If proprietary information is submitted, it must be appropriately and specifically marked as “Proprietary.” It is the submitter's responsibility to clearly define to the Government what is considered mailto:osd.pentagon.rsrcmgmt.list.sda-sn-23-0001@mail.mil mailto:OSD.SDA.Proposals@mail.smil.mil.

mailto:SDA.Proposals@osdj.ic.gov mailto:osd.pentagon.rsrcmgmt.list.sda-sn-23-0001@mail.mil

Page - 6 proprietary data. SDA will not publicly disclose proprietary information obtained as a result of the RFI. To the full extent that it is protected pursuant to the Freedom of Information Act and other laws and regulations, information properly identified by a respondent as “Proprietary” will be appropriately controlled. Submissions may be reviewed by Government personnel and support contractors bound by appropriate non-disclosure agreements. Responses to this RFI will not be returned. Intellectual or other privileged or proprietary information contained in responses to this RFI will not be distributed outside of the Department of Defense or United States Government employees from other Government agencies who are working with SDA on this RFI. Respondents are advised that SDA is under no obligation to acknowledge receipt of the information received or provide feedback with respect to any information submitted under this RFI. Responses to this RFI do not bind SDA to any further actions.