In this paper, we describe the application of an emitter array based on simultaneous transmit-synthetic aperture beamforming (ST-STAB) to improve the signal-to-noise ratio in an existing, 3-D, air-coupled sonar system...
详细信息
In this paper, we describe the application of an emitter array based on simultaneous transmit-synthetic aperture beamforming (ST-STAB) to improve the signal-to-noise ratio in an existing, 3-D, air-coupled sonar system. The ST-STAB approach allows for the simultaneous emission of orthogonal codes by an array of emitters, which are decoded in the receiver stage, eliminating the need for multiple measurement cycles. By adding more emitters to the sensor system, the overall emitted acoustic energy is increased, while the ST-STAB approach ensures an efficient use of measurement time. We elaborate on the mathematical model of the sensor and signal processing system, provide the associated point spread functions and show experimental validation the constructed prototype array.
Moving a sensor through its environment creates signature time variations of the sensor's readings often referred to as flow cues. We analyze the acoustic flow field generated by a sonar sensor, capable of imaging...
详细信息
Moving a sensor through its environment creates signature time variations of the sensor's readings often referred to as flow cues. We analyze the acoustic flow field generated by a sonar sensor, capable of imaging the full frontal hemisphere, mounted on a mobile platform. We show how the cues derived from this acoustic flow field can be used directly in a layered control strategy, which supports a robotic platform to perform a set of motion primitives, such as obstacle avoidance, corridor following, and negotiating corners and T-junctions. The programmable nature of the spatial sampling pattern of the sonar allows efficient support of the varying information requirements of the different motion primitives. The proposed control strategy is first validated in a simulated environment and subsequently transferred to a real mobile robot. We present simulated and experimental results on the controller's performance while executing the different motion primitives. The results further show that the proposed control strategy can easily integrate minimal steering commands given by a user (electric wheelchair application) or by a high-level navigation module (autonomous simultaneous localization and mapping (SLAM) applications).
Joule heated resistive emitter arrays are presently limited to pixel temperatures on the order of 1000 K. A phase 2 SBIR program is underway to develop material sets with the goal of increasing the operating temperatu...
详细信息
ISBN:
(纸本)0819462640
Joule heated resistive emitter arrays are presently limited to pixel temperatures on the order of 1000 K. A phase 2 SBIR program is underway to develop material sets with the goal of increasing the operating temperatures of these arrays by up to a factor of 3. Preliminary work indicates that transition metal oxides and carbides are the most promising materials for 3000 K pixel temperatures. An overview of the project and current status is presented. Thin films will be deposited by numerous vendors using a variety of techniques, and annealed at ultra-high temperatures in vacuum to select the most stable materials. Test emitter pixel arrays will be fabricated and tested.
Numerous infrared scene projection technologies have been investigated since the 1970s. Notably, from the late 1980s the development of the first resistor array infrared projectors gained leverage from the strong conc...
详细信息
ISBN:
(纸本)0819457701
Numerous infrared scene projection technologies have been investigated since the 1970s. Notably, from the late 1980s the development of the first resistor array infrared projectors gained leverage from the strong concurrent developments within focal plane array imaging technology, linked by the common need for large integrated circuits comprising a 2-dimensional array of interconnected unit cells. In the resistor array case, it is the unit cell comprising the resistively heated emitter and its dedicated drive circuit that determines the projector response to its associated scene generator commands. In this paper we review the development of resistor array technology from a historical perspective, concentrating on the unit cell developments. We commence by describing the technological innovations that forged the way, sharing along the way stories of the successes and failures, all of which contributed to the steady if somewhat eventful growth of the critical knowledge base that underpins the strength of today's array technology. We conclude with comments on the characteristics and limitations of the technology and on the prospects for future array development.
The development of a new generation PC-based array control electronics (PACE) system was completed during the first quarter of 2003 in the Kinetic Kill Vehicle Hardware-in-the-loop (KHILS) facility. This system replac...
详细信息
ISBN:
(纸本)0819449520
The development of a new generation PC-based array control electronics (PACE) system was completed during the first quarter of 2003 in the Kinetic Kill Vehicle Hardware-in-the-loop (KHILS) facility. This system replaces the bulky VME-based system that was the previous standard with more compact digital control electronics using field-programmable gate array (FPGA) technology hosted on a personal computer. The analog interface electronics (AIE) were redesigned to eliminate obsolete components and miniaturize the package for better compatibility with harsh environments. The resulting PACE system supports both Santa Barbara Infrared Inc. (SBIR) and Honeywell Technology Center's (HTC's) 512 x 512 legacy emitter array infrared projection devices as well as SBIR's upcoming 1024 x 1024 and next-generation 512 x 512 arrays. Two FPGA-based PCI boards enable this system to reconfigure the inputs, processing and outputs of the projection electronics through firmware loaded from the control PC. The increased flexibility provides potential for additional real-time functions such as distortion correction, convolution and calibration to be implemented along with nonuniformity correction (NLJC) techniques by simply reconfiguring firmware. This paper describes the capabilities of the new PACE system in terms of current and future hardware-in-the-loop (HITL) requirements.
暂无评论