SITIS Topic Details |
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| Proposals Accepted: | |
| Program: | SBIR |
| Topic Number: | A10-150 (Army) |
| Title: | Near Infrared Stretched Pulse Processing | Research & Technical Areas: | Sensors, Electronics |
| Acquisition Program: | PEO Missiles and Space |
| The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), which controls the export and import of defense-related material and services. Offerors must disclose any proposed use of foreign nationals, their country of origin, and what tasks each would accomplish in the statement of work in accordance with section 3.5.b.(7) of the solicitation. | Objective: | The goal of this effort is to develop a high-fidelity; near-infrared projector system capable of simulating the laser return signals representative of those encountered in real-world SAL engagements. The system must have the capability to project complex optical waveforms through control of their spatial and temporal characteristics. This system would greatly expand the Army’s ability to test new SAL sensor designs and avoid costly and often incomplete field testing or, worse yet, finding problems during combat conditions.
| Description: | To evaluate, characterize, or test Semi-active laser (SAL) sensors in a laboratory or hardware-in-the-loop environment requires simulating the laser return signal produced by optical pulses from a laser designator illuminating a target. Presently, the representation of the laser return (pulse) signal is quite simple, being represented as a Gaussian spot with a fixed angular size whose intensity can vary to simulate closure on the target. However, real-world laser return signals can be significantly corrupted both spatially and temporally by atmospheric and surface reflection factors resulting in one or more complex return signals for a given designator pulse. This spatial and temporal complexity may critically impact the sensor performance during acquisition, tracking and aim point selection.
The primary result of spatial corruption is to introduce non-uniformity into the intensity profile of the laser return signal. The non-uniformity is due primarily to the non-uniform reflectivity of the surface illuminated by the laser beam. Another factor of the spatial corruption is the atmospheric conditions, i.e., contributions from dust or smoke which may be present in the atmosphere. The dust and smoke particles scatter and/or absorb the laser radiation (direct or reflected) as it travels through the atmosphere. The density of dust or smoke can vary greatly over the path the optical radiation may travel thereby leading to significant spatial non-uniformities in the return beam profile. Further, range closure alone will significantly change the size of the observed laser pulse during the final, critical stages of engagement.
The primary result of temporal corruption is characterized by stretching, or splitting, of the original laser pulse. Pulse stretching can occur due to the geometrical relationship between the angle at which the designator pulse strikes the target surface and the angle at which the sensor observes the laser return signal. Atmospheric conditions (i.e., dust or smoke) can also contribute to the pulse stretching. Along with pulse stretching, the intensity profile of the laser return radiation may vary over the extent of the pulse length.
The desired laser pulse system should be capable of generating laser pulses with a temporal resolution of one nanosecond across a total period up to 100 nanoseconds. Spatial pulse representation should be 256x256 with pulse spatial widths dynamically controlled across a range of 0.5-20 mrad. Amplitude dynamic range should be >20dB both within the spatial cross-section and across the full temporal profile. The requirements cited are viewed as extremely challenging and not readily available in the commercial segment and pose a high degree of technical risk.
The pulsed laser system should be compatible with current government HWIL operations and be able to be integrated with existing communications infrastructure within the HWIL simulation systems. The pulsed laser system should also support real-time operation (>40 Hz) with minimal latency (<10 msec). Presently, the only time that real-world excitations for Near IR sensors occur is during field testing such as captive flight, tower tests or flight tests. Effective testing in a controlled environment i.e. laboratory will not only result in better system performance but could potentially result in significant cost and schedule reduction in problems which are identified prior to field testing.
The current lasers used to test sensors in the laboratory environment produce a uniformly distributed energy pulse i.e. Gaussian spot. The proposed product is to provide the capability to be able to produce an energy pulse that is representative of the effects seen in the real-world in the laboratory environment. As such, the war-fighter will be provided with either a weapon or sensor system that is more robust by being able to improve the algorithms within the Near Infrared (NIR) sensors prior to flight tests or in field applications.
| PHASE I: Develop a detailed system design of the laser pulse simulator supporting the technical specifications described above. Specifically address the costs and technical risks associated with the proposed approach.
| PHASE II: During this phase of the program the intent is to transition the proposed system design to a proto-type system which can be integrated with a hardware-in-the-loop projection system or some other projection system to demonstrate the ability to apply intra-pulse modulate to the NIR signal.
| PHASE III: The proposed stretched pulse laser system (Near Infrared –NIR) will be transitioned to and used by US ARMY AMRDEC to enhance testing of multi-spectral, in particular the near infrared (NIR) band, sensor systems in relevant environments. The capability could also used by both the US Air Force and US NAVY to test such weapons systems as Joint Air-to-Ground Missile, Small Diameter Bomb and Small Diameter Bomb Increment II (SDBII), and HELLFIRE. Possible commercial applications could be in the areas of inventory control (bar code scanning technology), manufacturing (increased precision due to high rate modulation), and digital elevation mapping (improved resolution is digital elevation measurements).
| References: | 1. Temporal Pulse Spreading of a Return LIDAR Signal; R. Krawczyk, O. Goretta, A. Kassighian; Applied Optics, Vol. 32, pp 6784-6788 (1993) 2. Target Detection Method Based on the Single Laser Return Waveform; Z. Nanxiang, H. Yihua, H. Min; Proceedings of SPIE Vol. 7382, International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging F. Amzajerdian, et al/, Ed. Paper, 2009 3. Semi-Active Laser (SAL) Last Pulse Logic Infrared Imaging Seeker; J.E. English, R.O. White; Proceedings of SPIE Vol. 4372, Infrared Imaging systems: Design, analysis, Modeling, and Testing XII, G.C Holst, Ed., pp. 126-136, 2001 |
| Keywords: | Semi-active laser projector, near-infrared (NIR), hardware in the loop (HWIL), simulations |
Questions and Answers: |
Q: I am trying to understand the laser modulation method used in the current SAL simulator. 1. Are the source lasers running in CW mode but being modulated by attenuators that receive variable-frequency electronic signals? |
A: 1. The present system is a pulsed laser with no intra-pulse modulated applied. The output of the laser is passed through EO modulators to control the energy level at the unit under test which is representative of the reflected energy of the designator as seen by the unit under test. |
Q: How would you rank the following evaluation criteria for proposed alternative solutions? |
A: The SBIR Evaluation process provides guidance on the assessment of the proposal. At the point in time when the evaluation begins, guidelines will be set forth on proposal evaluations. At this point in time an answer to this question cannot be provided. |
Q: 1. I'm wondering what is the desired laser power and wavelength? |
A: 1. I'm wondering what is the desired laser power and wavelength? |
As of midnight September 1, questions for solicitations SBIR 10.3 and STTR 10.B will no longer be accepted.
To read the solicitation for full proposal preparation and submission details click here. |