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Small Business Innovation Research
2001 Program Solicitation
DTRS57-01-R-SBIR

Technical Questions and Answers (UPDATED 04/05/01)

Program Contents

• QUESTION: Please clarify your statements as to "stand-alone capability" and "without reliance on external signals" in regard to the type of device envisioned.
• QUESTION: If the GPS Service is lost or compromised, how long must the back-up system provide the accuracy required for non-precision approach?
• QUESTION: "Is this what FAA envisions for a backup system"?
• QUESTION: In SBIR topic 01-FR2, what are the web site addresses for "1999 passenger equipment safety standards of FRA" and "the research work for a glazing standards of the American Public Transportation Association(APTA)"?

QUESTION: Please clarify your statements as to "stand-alone capability" and "without reliance on external signals" in regard to the type of device envisioned.

ANSWER: While other forms of "autonomous" navigation systems could be considered viable candidates for this topic area, such as terrain mapping and synthetic vision, these devices rely ultimately on some form of external sensor or probe outside of the aircraft. Additionally, ongoing research programs by FAA and NASA are currently addressing these areas.

The primary intent of this topic is to focus technology on the specific area of developing an affordable Inertial Navigation System requiring "no" external sensors. Further, it is expected that accelerated development of low-cost "MicroElectroMechanical Systems" (MEMS) devices and/or "Fiber Optic Gyroscopes" will become key components for use in building a low-cost INS device for General Aviation.

QUESTION: If the GPS Service is lost or compromised, how long must the back-up system provide the accuracy required for non-precision approach?

ANSWER: One estimate would be on the order of 4-5 hours. However, this is not an easy question to answer because it hinges on the interdependence of navigation system failure mode, enroute weather conditions and individual aircraft speed/range characteristics. In an attempt to arrive at a reasonable answer, setting a rough "ground rule" - so to speak, let's consider the following. First, we will make the assumption that an aircraft contemplating a flight into known or expected "instrument meteorological conditions" would not depart without an "operable" GPS as the primary navigation capability. Second, we will acknowledge that the source of GPS failure could be from any of several causes, and may constitute permanent loss of GPS capability for the duration of the flight. (Envisioned are: onboard equipment failure, the loss of signal due to sunspot activity, unintended radio interference or deliberate jamming.) Third, the need for back-up capability could extend from the point of take-off (assuming departure in IMC) until an approach can be made to a suitable landing field, i.e. one having "at least" a minimal non-precision approach. This could be for a protracted length of time and (in the worst case) ultimately correspond to the range limitations of the individual aircraft. Hence, an honest attempt at an answer would be to place such "time interval" towards the outer limits of an "average" GA aircraft's endurance range.

QUESTION: "Is this what FAA envisions for a backup system"?

ANSWER: At this time, neither system requirements nor operational scenarios have been established for a back-up system to GPS that could be used by general aviation interests. Likewise, no certification standards have been established for any apparatus that would perform such a function. Any certification action would become the burden of an individual applicant. This SBIR topic broaches the subject, from a safety/benefit point of view, by soliciting from industry their best attempt to provide an affordable system that would complement GPS, commensurate with developing sensor technologies.

QUESTION: In SBIR topic 01-FR2 "Safety Glazing design for Passenger Rail Vehicles," you refer to the "1999 passenger equipment safety standards of FRA" and "the research work for a glazing standards of the American Public Transportation Association(APTA)."

What are the web site addresses for both these references?

ANSWER: The first one has been published as 49 CFR Part 216 et al, in the Federal Register, vol 64, No. 91, May 12, 1999.

The second one has not been published.