Rapid Scalable Time Synchronization

Navy SBIR 24.1 - Topic N241-044
NAVSEA - Naval Sea Systems Command
Pre-release 11/29/23   Opens to accept proposals 1/03/24   Now Closes 2/21/24 12:00pm ET    [ View Q&A ]

N241-044 TITLE: Rapid Scalable Time Synchronization

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Advanced Computing and Software

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.

OBJECTIVE: Develop a rapid time synchronization capability for nodes that use single beam antennas in a Global Positioning System (GPS) denied environment.

DESCRIPTION: As modern networking technology has proliferated, the "Internet of Things" describes the increasing interconnectivity of devices at all layers of modern society. This has enabled sharing of information and coordination of operation in real time across a wide range of applications, in particular allowing for comprehensive control of devices by centralized or distributed command structures. Recent industry gains in this area have provided an opportunity to leverage modern networking technology to reduce communications operations overhead by integrating much more efficient networking methods. Time sync has been identified as a specific area where significant gains can be realized that will make larger fleet operations much more robust and flexible.

The Navy is tasked with connecting, improving, and expanding over-the-air tactical network functionality to support expanded mission areas and new and evolving future warfighting capabilities. Time synchronization is an essential requirement for Navy networked sensor systems to perform their primary mission, which relies on sensor data distributed across the network. The existing time sync methods are laborious and slow, necessitating specific input from operators and disruption to network operations. Incorporation of modern, Transportation Control Protocols / Internet Protocols (TCP/IP) time sync methodologies, specifically the methodologies utilized in wireless fidelity (Wi-Fi) switches and routers, into the larger communications system would reduce this operational overhead. This has great value as networks increase in node size consistent with integrated Naval operations currently being developed.

The Navy network is a C-Band, maritime, half-duplex, line of sight network of mobile nodes including both ships and aircraft. This networking capability needs to be as agile as possible to enable utmost flexibility for the warfighter. A time sync capability with the desired performance will enable large networks to form more rapidly, as time sync is the first step in network formation. It will also enable new nodes to enter an existing network in much less time. This will enable the warfighter to respond more rapidly to changing battle space conditions.

The Navy needs a rapid time sync capability for nodes that use single beam antennas in a GPS denied environment for nodes in a large, directional, half duplex, C-band, microwave, maritime, mobile network that uses single beam antennas, but can be extended to multi-beam capability. There is currently no commercial capability known that can do this. The capability should optimize transmit power and minimize total power required given an available Effective Isotropic Radiated Power (EIRP) of approximately 50 decibel-Watt (dbW).

The solution must leverage protocols from technologies developed for, and used in, 5G and other modern communications networks, such as Precise Timing Protocol (PTP) and Network Time Protocol (NTP), while maintaining sub-microsecond (i.e., current state of the art with PTP for wired networks) accuracy within a mobile, wireless network. A key improvement sought is minimizing prime power required from the supporting platforms. This will enable application to a larger number of smaller platforms. The goal is to use no more power than required in the mobile maritime environment. The protocol should adaptively determine what is required. The maximum available EIRP is 52.2 dBW. The threshold requirement for time accuracy is sub-microsecond with an objective of 100 nanoseconds. The time sync protocol should meet its performance requirements without GPS but should be able to use it when available. It shall adapt to varying radiated power limits placed on the network, with the capability to provide accurate solutions even when operating at reduced power. It shall be scalable to many moving platforms with a threshold of dozens of nodes to an objective of 100 nodes, accomplishing time sync for this network within 2 minutes or less. It shall not require prior knowledge of node locations. It may use directional or Omni antennas or both. Finally, it must do all of this in a contested, congested, and constrained Naval electromagnetic and electronic warfare environment as described in the 2020 Department of Defense Electromagnetic Spectrum Superiority Strategy and MIL-STD-461G requirements.

Classified legacy time sync requirements in Navy network system specifications shall provide a baseline against which the prototype will be compared.

Work produced in Phase II may become classified. Note: The prospective contractor(s) must be U.S. owned and operated with no foreign influence as defined by 32 U.S.C. § 2004.20 et seq., National Industrial Security Program Executive Agent and Operating Manual, unless acceptable mitigating procedures can and have been implemented and approved by the Defense Counterintelligence and Security Agency (DCSA) formerly Defense Security Service (DSS). The selected contractor must be able to acquire and maintain a secret level facility and Personnel Security Clearances. This will allow contractor personnel to perform on advanced phases of this project as set forth by DCSA and NAVSEA in order to gain access to classified information pertaining to the national defense of the United States and its allies; this will be an inherent requirement. The selected company will be required to safeguard classified material during the advanced phases of this contract IAW the National Industrial Security Program Operating Manual (NISPOM), which can be found at Title 32, Part 2004.20 of the Code of Federal Regulations. Reference: National Industrial Security Program Executive Agent and Operating Manual (NISP), 32 U.S.C. § 2004.20 et seq. (1993). https://www.ecfr.gov/current/title-32/subtitle-B/chapter-XX/part-2004

PHASE I: Develop a concept for a rapid time sync capability for a network of mobile maritime nodes using a line of sight C-band microwave link. Demonstrate the concept can feasibly meet the Navy requirements as provided in the Description. Establish feasibility by a combination of analysis and modeling. The modeling should include maritime ducting conditions resulting in signal degradation [Ref 4]. The Phase I Option, if exercised, will include the initial design specifications and capabilities description to build a prototype solution in Phase II.

PHASE II: Develop and deliver a prototype rapid time sync capability based on the results of Phase I. Demonstrate that the prototype meets the performance parameters outlined in the Description. Testing, evaluation, and demonstration are the responsibility of the awardee but government subject matter experts will validate the improvements achieved by the prototype.

It is probable that the work under this effort will be classified under Phase II (see Description section for details).

PHASE III DUAL USE APPLICATIONS: Support the Navy in transitioning the technology to Navy use. Further refine the prototype for evaluation to determine its effectiveness and reliability in an operationally relevant environment. Support the Navy in the system integration and qualification testing for the technology through platform integration and test events to transition the technology into Navy applications for simultaneous communications links to improve and expand tactical network functionality. A substantial amount of this Phase’s effort will be in integrating the new time sync protocol with the pre-existing networking code.

High-performance time sync protocols will have direct application to private sector industries that involve mobile microwave networks. These applications include transportation and communication industries.


  1. Zhang, Chenyu; Zheng, Wei; Wen, Xiangming; Lu, Zhaoming; Wang, Luhan and Wang, Zhengying. "TAP: A High-Precision Network Timing Method Over Air Interface Based on Physical-Layer Signals." IEEE Access, Vol. 7, 2019. https://ieeexplore.ieee.org/document/8926458
  2. Shi, Haochuan; Aijaz, Adnan and Jiang, Nan. "Evaluating the Performance of Over-the-Air Time Synchronization for 5G and TSN Integration." arXiv:2104.13873v1 [cs.NI], 28 Apr 2021. https://arxiv.org/pdf/2104.13873.pdf
  3. Garg, A. Yadav; Sikora, A. and Sairam, A.S. ‘‘Wireless precision time protocol.’’ IEEE Commun. Lett., vol. 22, no. 4, Apr. 2018, pp. 812–815. https://ieeexplore.ieee.org/document/8171749
  4. Mahmood, A.; Ashraf, M.I.; Gidlund, M. and Torsner, J. "Over-the Air Time synchronization for URLLC: Requirements, Challenges and Possible enablers." IEEE Int. Symposium Wireless Commun. Sys. (ISWCS), 2018, pp. 1-6. https://arxiv.org/pdf/1807.00078
  5. Park, J.Y.; Encarnado, F.S.; Flint, C.R. and Redwine, K.H. "Characterization and Modeling of Frequency-Selective Ship-to-Ship Channels." MILCOM 2021, IEEE, 2021. https://ieeexplore.ieee.org/document/9652980

KEYWORDS: Time synchronization; over-the-air tactical network; precise timing protocol; Effective Isotropic Radiated Power; scalable to many moving platforms; Global Positioning System (GPS) denied.


The Navy Topic above is an "unofficial" copy from the Navy Topics in the DoD 24.1 SBIR BAA. Please see the official DoD Topic website at www.defensesbirsttr.mil/SBIR-STTR/Opportunities/#announcements for any updates.

The DoD issued its Navy 24.1 SBIR Topics pre-release on November 28, 2023 which opens to receive proposals on January 3, 2024, and now closes February 21, (12:00pm ET).

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Topic Q & A

1/11/24  Q. Question 1: Will the time synchronization system interface directly with the C-band microwave link and be the sole user of the link, or is the link shared with other systems?
Question 2: What is the interface to the C-band microwave link, is it at the physical layer (e.g. RF at C-band or at an intermediate frequency/IF - something less than C-band), or at a higher network level (e.g. Data Link, Network, etc)?
   A. Answer 1: The time synchronization protocol will be a part of the command and control systems associated with the C-band microwave link (network). This system is the sole user of the time synchronization protocol, however, this is a distributed system amongst a number of C-band microwave network nodes. This dedicated use ensures that the system has exclusive access to the link for accurate time synchronization.
Answer 2: The time synchronization protocol will be implemented at the OSI TCP/IP Network Layer (3) within the systems command and control element. The time synchronization protocol will be distributed across the network at the OSI TCP/IP Physical Layer (1) with RF @ C-Band.

End of QA
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