GPS Interference Direction of Arrival (DoA) Initiative for User Purposes (GIDI-UP)

Navy SBIR 22.4 - Topic N224-130
NAVWAR - Naval Information Warfare Systems Command
Opens: August 11, 2022 - Closes: September 13, 2022 (12:00pm est)    [ View Q&A ]

N224-130 TITLE: GPS Interference Direction of Arrival (DoA) Initiative for User Purposes (GIDI-UP)


TECHNOLOGY AREA(S): Electronics; Sensors

OBJECTIVE: Develop Global Positioning System (GPS) interference direction finding sensor for surface and subsurface vessels to provide situational awareness of jamming and/or spoofing signals.

DESCRIPTION: GPS is a highly accurate all-weather source of positioning, velocity, and timing (PVT) and is invaluable in bounding a ship’s inertial navigation system’s (INS) error. However, GPS utilizes weak radio frequency (RF) signals from distant satellites and are subjected to intentional and unintentional interference. Furthermore, users of GPS desire to ascertain the presence of undesired competing signals that may degrade or deceive platform GPS systems.

Surface platforms have multi-element anti-jamming antenna systems on board for the purposes of nulling/degrading antenna pattern in the direction of interference signals that are above the thermal noise defined by kTB. The GIDI-UP capability seeks to leverage the antenna arrays for the purposes of interferometry to detect and inform the host GPS-based Positioning Navigation and Timing Service (GPNTS) and ships bridge systems of the DoA of unwanted signals such that might be performing jamming and spoofing.

Phased array antenna technology is capable of directing antenna gain patterns for the purposes of electronically steerable arrays which is a well-known process. For GIDI-UP, a capability is required to provide directional accuracy of less than one (1) degree of azimuth and elevation (Threshold)/0.5 degrees (Objective). Capability shall include developing up to six (6) independent records for detected jammers/spoofers. Each DoA record will include bearing and elevation, including percent uncertainty for each separately. Data output will be in the North East Down coordinate frame.

The end solution will integrate into Position, Navigation, and Timing (PNT) suites, such as GPNTS. GPNTS is the Navy’s current and modernized PNT system, replacing the Navigation Sensor System Interface (NAVSSI). It is an open-architecture, data-hosting environment for Navy surface platforms and provides real-time PNT data services, while allowing the integration of future APNT sources.

PHASE I: Determine the technical feasibility of using measurements of DoA for interferers. Identify the suitability of antenna arrays (considering the use of existing shipboard arrays configurations) necessary to detect and provide DoA information.

Describe the technical solution based on the investigation and technical trade-offs performed earlier in this Phase. Identify the means to incorporate the technical solution into the PNT suite, such as the GPNTS.

For the identified solution, develop the SBIR Phase II Project Plan to include a detailed schedule (in Gantt format), spend plan, performance objectives, and transition plan for the identified Program of Records (PoRs).

PHASE II: Develop a set of performance specifications for the GIDI-UP sensor with a positioning solution system for GPNTS. Conduct a System Requirements Review (SRR).

Engage with the Program Office during the introduction and collaboration with Naval Information Warfare Center (NIWC) Pacific engineers. Establish a working relationship with PMW/A 170 and NIWC Pacific engineers to perform integration studies to include the identification of any necessary engineering changes to the current GPNTS system. Additionally, establish a working relationship with the engineering team(s) of other potential transition PNT suite target(s).

Develop the prototype GIDI-UP sensor with positioning solution system for demonstration and validation in the GPNTS or equivalent development environment. Conduct a Preliminary Design Review (PDR) and commence development of an Engineering Development Model (EDM) system. Conduct a Critical Design Review (CDR) prior to building the EDM.

Develop the life-cycle support strategies and concepts for the system.

Develop a SBIR Phase III Project Plan to include a detailed schedule (in Gantt format) and spend plan, performance requirements, and revised transition plan for the GPNTS and other potential transition PNT suite target(s).

PHASE III DUAL USE APPLICATIONS: Refine and fully develop the Phase II EDM to produce a Production Representative Article (PRA) of the GIDI-UP sensor.

Perform Formal Qualification Tests (FQT) (e.g., field testing, operational assessments) of the PRA GIDI-UP sensor with the GPNTS system and other potential transition PNT suite target(s).

Provide life-cycle support strategies and concepts for the GIDI-UP sensor with the GPNTS and other potential transition PNT suite contractor(s) by developing a Life-Cycle Sustainment Plan (LCSP).

Investigate the dual use of the developed technologies for commercial applications, including but not limited to, commercial and privately owned vessels. These sensors can provide an additional method of positioning that is independent of GPS and available at all times, worldwide.


  1. Xu, Zili and Trinkle, Matthew. "Weak GPS Interference Direction of Arrival Estimation Using GPS Signal Cancellation." Proceedings of the 25th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2012), Nashville, TN, January 2012, pp. 2940-2945.
  2. Schmidt, R.O. "Multiple Emitter Location and Signal Parameter Estimation." IEEE Trans. Antennas Propagation, Vol. AP-34 Issue 3 (March 1986), pp. 276–280.
  3. Barabell, A. J. et al. "Performance Comparison of Superresolution Array Processing Algorithms. Revised." MIT Lincoln Labs, 1998.
  4. Fishler, Eran and Poor, Vincent, H." IEEE Transactions on Signal Processing, Volume: 53, Issue: 9, Sept. 2005.."
  5. Rothmaier, F.; Chen, Y.; Lo, S. and Walter, T. "GNSS Spoofing Detection Through Spatial Processing." Journal of the Institute of Navigation, 68 (2), June 2021, pp. 243-258.

KEYWORDS: Global Positioning System; GPS; Position Navigation and Timing; PNT; Assured PNT; APNT; direction of arrival; DoA



The Navy Topic above is an "unofficial" copy from the Navy Topics in the DoD 22.4 SBIR BAA. Please see the official DoD Topic website at for any updates.

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** TOPIC Q&A **
Questions 08/02/22
Q1. What objective(s) is the Navy trying to achieve with this topic?
A1. The objective of this effort is to develop a Global Positioning Systems (GPS) interface direction finding sensor for an existing GPS 7-element planar array for situational awareness of jamming and/or spoofing signals. The requirement is to provide directional accuracy of less than 1 degree of azimuth and elevation (Threshold)/0.5 degrees (Objective). Additionally, the output of this system will be provided to the GPS-based Positioning Navigation and Timing Service (GPNTS) on surface and subsurface vessels.
Questions 08/25/22
Questions:    1. Does the existing 7 element planar array provide interference suppression/cancellation?
2. Does the contractor receive manifolds, ICDs, etc, for the relevant systems?
3. What Hardware is provided?
1. The below comment indicates an antenna array. However, there are also tuners, digitizers and compute HW (e.g., FPGAs or GPUs) that a system will need.

  1. No. We are only interested in you system interfacing with the RF feed points for each of the 7 elements. There is a separate system that performs interference mitigation processing, but it should be considered separate from this project.
  2. More details about the antenna array can be provided post award. You can expect to formulate the manifold vectors as part of this effort.
  3. We will not be providing any hardware. There should be no presumption that GIDI-UP is to be implemented using existing hardware as this is a new development. The GIDI-UP Phase 1 SBIR project is to develop a concept that would use performing contractor selected/developed hardware, software defined hardware, and software necessary to perform angle/direction of arrival functions.

Questions 08/25/22
Questions:    A. Can you provide the geometry/dimensions of the current 7-element planar array?
B. Can we assume the array manifold of the desired 7-element antenna array will be made available?
C. Are there multiple such arrays onboard the platform, and what are their relative geometry?
D. Can you provide example or target surface platforms?
E. Can additional antennas be utilized in the solution?
F. What are the incident interferer signal levels that must be detectable/located by the solution?
G. Is there an associated Program of Record?

  1. The antenna is 14 inch diameter array with 6 elements around the periphery and an element in the center. Further details will be provided post award.
  2. More details about the antenna array can be provided post award. You can expect to formulate the manifold vectors as part of this effort.
  3. This effort should presume availability to a single array.
  4. The platform will be Navy surface ship.
  5. No.
  6. We are interested in signal levels above kTB because GPS signals are significantly below that.
  7. If successful this capability will be integrated into the GPS-based Positioning Navigation and Timing Service (GPNTS)
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