DIGITAL ENGINEERING - Broadband Real-time Data Bus

Navy SBIR 23.1 - Topic N231-008
NAVAIR - Naval Air Systems Command
Pre-release 1/11/23   Opens to accept proposals 2/08/23   Closes 3/08/23 12:00pm ET    [ View Q&A ]

N231-008 TITLE: DIGITAL ENGINEERING - Broadband Real-time Data Bus


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 an open protocol, software and hardware to support the use of IP devices (e.g., an Ethernet-enabled sensor with an Ethernet-enabled mission computer system) over a STANAG-7221 link without interfering with a MIL-STD-1553 connection being used concurrently.

DESCRIPTION: Many currently fielded Navy platforms use the serial bus standard MIL-STD-1553. The standard features multiple redundant balanced line physical layers, a (differential) network interface, time division multiplexing (TDM), half-duplex command/response protocol, and can handle up to 30 devices. Typically, this ensures that platforms have twin-axial (co-axial) cabling installed throughout the asset, even including weapons interfaces, which connect to external mounted weapons or information pods. The data rate exhibited by MIL-STD-1553 (around 1 Mbps) is insufficient for many platform data requirements,; for example, full motion video surveillance, software defined radio interfaces, and raw radar data transfer. In 2016, STANAG 7221 was introduced, which described the Broadband, Real-Time Data Bus (BRTDB) Standard which supports up to 200 Mbps data transfer over the same twin-axial cabling currently in the platforms without interfering with the existing MIL-STD-1553 data transfer. Essentially STANAG 7221 utilizes a Digital Service Link (DSL)-like frequency division multiplexed (FDM) architecture. Digital Service Link is defined as the following: transport service delivered via the internet or other electronic network, which is automated and requires little to no human intervention to operate. For this SBIR topic, implementing STANAG 7221 implies the higher data rate (and higher frequency) STANAG 7221 signals can co-exist with the standard MIL-STD-1553 signals (at lower frequency). Co-existence of these signals on a single bus is by this definition, "high data rate" and using spread spectrum (signals at high and low frequencies) in an FDM architecture constitutes "Broadband."

This feature is extremely powerful considering the difficulty involved with changing cable configurations on aircraft (impacting the Operational Flight Plan) and changing cable configurations on Navy ships (impacting the certified ship configuration).

With most sensors and computing devices supporting IP over Ethernet, in a typical environment these items can easily be added, removed, or moved in a platform network with a simple configuration change and the movement of some standard connectors, often RJ-45 or MIL-DTL-38999. In contrast, the use of STANAG 7221 requires some significant development effort to adapt a device specific proprietary interface to the 7221 data physical layer at both source and destination.

The proposed solution should support Standard Network Management Protocol v3 (SNMP) for management and statistics, or an equivalently acceptable standard. The design should consider warfighter ease of use to create a data bus that is legacy compatible and does not impact the standard 1553 bus configuration, effectively "plug and play," to enable STANAG 7221 speeds for IP-based traffic simultaneously. Warfighter input as a key design input is recommended. This solution should be prototyped and tested against programmatic requirements and not require a Depot maintenance cycle to implement (i.e., be installed either at the Operational or Intermediate level of maintenance, i.e., "drop in" or "Plug and Play" without any required user configuration once installed.)

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 DoD 5220.22-M, National Industrial Security Program 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 NAVAIR 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 IAW DoD 5220.22-M during the advanced phases of this contract.

PHASE I: Create and demonstrate the feasibility of a real-time broad band data bus capable of supporting legacy MIL-STD-1553. and also demonstrate transmission of data at a higher data rate, higher bandwidth traffic on a common data bus. Methods for bridging data and providing link status should be investigated. Issues associated with using STANAG 7221 should be investigated and mitigated. The Phase I effort will include prototype plans to be developed under Phase II.

PHASE II: Develop a prototype hardware solution with integrated software, which is able to drop in and provide IP connectivity at STANAG 7221 speeds over MIL-STD-1553 bus with no manual configuration required.

Work in Phase II may become classified. Please see note in Description paragraph.

PHASE III DUAL USE APPLICATIONS: Further develop, transition, and integrate a production level device, which can be installed on platforms and used to transport IP data at 7221 data rates over 1553 buses.

The commercial sector has mostly adopted higher data rate standards than MIL-STD-1553. However, the use of Time-Differential and Frequency-Differential modulation on the same channel has industry application and can be ported to analogous systems. This also serves as a precursor for Fiber Channel communications and Free Space Optics, which are used currently in industry and will later be adopted by Military armed forces once affordable, and coincident with a program that can leverage industry�s investments.


1.       Hearn, M. (n.d.). MIL-STD-1553B: The past and future data bus. High Frequency Electronics. Retrieved August 23, 2021, from

2.       AFLCMC/EN. (2018, February 28). MIL-STD-1553C: Department of Defense interface standard: Digital time division command/response multiplex data bus. Department of Defense.

3.       Department of Defense. (2006, February 28). DoD 5220.22-M National Industrial Security Program Operating Manual (Incorporating Change 2, May 18, 2016). Department of Defense.

4.       Hegarty, M. (2011, October). Leveraging MIL-STD-1553's physical layer for use in aircraft data networks. In 2011 IEEE/AIAA 30th Digital Avionics Systems Conference (pp. 7B1-1). IEEE.


KEYWORDS: Broadband; High Data Rate; FDM; TDMA; STANAG; Twin-Axial; Co-Axial


The Navy Topic above is an "unofficial" copy from the Navy Topics in the DoD 23.1 SBIR BAA. Please see the official DoD Topic website at for any updates.

The DoD issued its Navy 23.1 SBIR Topics pre-release on January 11, 2023 which opens to receive proposals on February 8, 2023, and closes March 8, 2023 (12:00pm ET).

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Topic Q & A

2/27/23  Q. 1. Is this SBIR asking for a proposal that includes the design of the analog function/analog interface necessary to capture the data driven over an existing physical medium (eg 1553 Data Bus) using the STANAG 7221 standard?
2. Is this SBIR asking for a proposal that only includes the digital PHY (Physical Layer Interface) and MAC interface necessary to capture the data driven from an existing MIL-STD-1553 data bus where a STANAG 7221 analog frontend already exists?
3. Assuming that the answer to question number 2 is yes, in addition to the digital PHY and MAC, are you also asking that the MAC be a new protocol supported by a software implementation of this protocol that is capable of offloading the data to an existing network?
   A. 1. The ability to capture data driven over legacy interfaces is acceptable in addition to the primary SBIR topic objective is acceptable
2. No. The ability to capture data from existing data busses is desired. An existing STANAG 7221 analog front end should not be assumed. Utilizing other interfaces in addition to STANAG 7221 to achieve the SBIR Topic�s objectives would also be considered acceptable
3. The ability to transfer or offload data to an existing network is desirable as long as the primary SBIR topic objective is met.

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