Advanced Sensor Technologies

ISL’s team consists of creative scientists and engineers with both theoretical and experimental expertise in the areas of physics, geophysics, oceanography, signal processing theory and application, nonlinear modeling, electro optics, and optical communications. Current work includes research and development of electric field detection sensor systems, electromagnetic performance prediction modeling, deep underwater gravity technology, modeling of factional network dynamics, modeling and hardware implementation of neurobiologically inspired networks, and long wave infrared chemical sensing technology. Salt Water Test Tank, EMI Screen Room, Prototyping Facilities.

Electric Field Detection Sensor System

ISL is developing a tactical electric field (E-Field) buoy and fixed bottom mounted E field sensors, both of which detect electromagnetic radiation from potential underwater threat targets. The sensors can be used in both shallow and deep water and are not affected by acoustic noise sources such as reverberation and clutter. Potential applications for the sensor include small area search and localization, as well as harbor security and protection.

Deep Underwater Gravity Technology

The AUV-based Deep Water Gravity program (ADWG), seeks to put a specially modified gravimeter inside an autonomous underwater vehicle (AUV) and run it near the bottom of the ocean, in order to measure gravity as close to the source mass as possible, and obtain higher resolution than equivalent shipboard geophysical measurements.

ISL has teamed with Scripps Institution of Oceanography (SIO) to implement this technology, and test it in a deep-water Bluefin AUV, for a consortium of interested oil exploration companies. The initial sea-test occurred in May of 2008 and demonstrated operational feasibility of the concept. Subsequent laboratory and pool tests have concentrated on identifying and eliminating the various external and internal forces that contaminate the geologic gravitational signal with noise. We are zeroing in on our goal of creating a system with 0.1-mGal rms measurement noise. Once that is achieved, the ADWG system will be a useful and marketable oil exploration technique, particularly in hard-to-access and deep water global frontier regions.

ISL has developed a detailed model to simulate the gravity and tensor gradient components for an arbitrary spatial distribution of density anomalies. In addition, a series of filters has been implemented that allow all other components (including the tensor gradient) to be derived from the vertical gravity component.

Marine Electric Field Sensor System

ISL’s innovative electric field sensor system provides an effective means for short range underwater surveillance in shallow water. The system combines proven underwater electrode technology, low-noise amplifiers, and a data acquisition system. The system is not affected by acoustic noise sources. Uses include:

  • Underwater marine surveillance
  • Harbor defense
  • False alarm reduction
  • Signature monitoring
  • Sensor calibration
  • Environmental noise monitoring
acrobat Marine Electric Field Sensor Specification Sheet (205KB)

Submarine Intercept and Analysis (IntAna) System

The IntAna system is a compact, low cost, open architecture, COTS-based intercept and analysis Sonar designed for installation on submarines operating in high density acoustic target/threat environments. IntAna provides submarine crews with real time capability to detect, track, and classify the full range of active sonar signals from surface ships, submarines, and underwater weapons for rapid and accurate tactical decision making. The 500 KHz acoustic bandwidth is the widest available in today’s market. Covering the frequencies of all ASW sonars, weapons, side scanning sonars, underwater communications devices, diver sonars, and fish-finding sonars, the IntAna system supports detailed passive acoustic analysis and recording of signals from numerous and varied passive sonar arrays and sensor configurations.

IntAna systems feature a flexible and intuitive graphical-user interface with extensive analysis and display tools that run under an advanced, commonly used operating system. The system processing and display software can easily be integrated into current or future combat and weapons control systems. Originally developed for the Royal Swedish Navy and currently deployed on several of their submarines around the world, IntAna systems are now being evaluated by several other countries for integration into their submarine combat systems.

Long Wave Infrared Chemical Sensing Technology

A hyperspectral imaging system consisting of a rapidly tunable, room temperature quantum cascade laser coupled with a mid-IR camera constitutes an avenue not previously explored. The presence of chemical residues can be determined from the measured reflection spectra and overlaid on a mid-IR image. The system allows for standoff detection and contains signal extraction algorithms that aid in the detection of chemical residues. The system is based on a tunable mid-IR source that can be rapidly tuned to precise wavelengths. Using these sources at wavelengths corresponding to chemical absorption features and synchronized with thermal imaging cameras, chemicals can be detected on various types of surfaces. Using advanced detection algorithms and image processing, the location and type of chemical can be superimposed upon a thermal image enabling efficient detection and identification to occur.

Electro Optics Design and Testing

ISL has extensive experience in systems analysis, optical design, optical prototyping and optical test and evaluation. Previous projects have included non-coherent LIDAR prototype, free space laser communications design and build, x-ray plasma laser driver design and build, x-ray microscope design and prototype, high power diffraction limited DPSS laser design and build, diffraction limited telescope design and build, atomic line filter design and build, LWIR system design and prototype, as well as many custom optical lens designs and builds. The latest design tools such as MATLAB, MathCAD, SolidWorks, and ZEMAX are all used in the performance of these projects.

Ultra Narrowband Optical Filters

Atomic line filters operating at various wavelengths from the near IR to the near UV have been extensively studied, since they are at present the narrowest bandwidth optical filters available. Their narrow bandwidth and relatively high sensitivity make them extremely useful for detecting weak, narrowband radiation embedded in a large continuous background. There are several types ranging from active to passive, wavelength converters, imaging filters, and ionization filters. They have been used extensively in LIDAR systems and other laser applications. ISL personnel have extensive experience designing and implementing atomic line filters in a variety of applications and can perform system analysis, design, prototyping, and test of these novel devices.

Passive RF Sensing

ISL maintains a Passive Coherent Location System (PCLS) test facility at our San Diego laboratory location. The facility is comprised of a rooftop antenna array, analog signal conditioning, and digital processing. The system is modular, configurable and programmable to satisfy customer target tracking objectives and the local radio frequency broadcast environment. Instead of using its own transmitter, this passive detection and tracking system processes common broadcast transmissions such as FM radio and television. The system is designed to track missile launches and has the capability to track aircraft and, in some cases, ground or sea-based moving targets. Our high fidelity simulation forecasts system performance, assists system configuration, supports development of novel radar modes, and assists in the data interpretation. The system has military, homeland defense, and commercial applications.

Persistent Surveillance Exploitation

Detection, tracking, and identification of targets in a complex environment with a high density of background traffic is very difficult. The number of detections and tracks generated by the background traffic can easily overwhelm an operator. Persistent surveillance sensors that can cover a wide area over a period of time can enable a unique capability to separate unusual or suspicious activity from the normal background activity. ISL has developed innovative processing techniques to quantify the normal activity in a given area and exploit this knowledge to identify suspicious activity, cue an operator with a high confidence detection of targets of interest, and to efficiently manage sensor resources.

Precision Geolocation and Georegistration

A wide variety of small, low cost, unmanned air vehicles (UAVs) carrying video sensors are increasingly deployed on today’s battlefield for intelligence, surveillance and reconnaissance (ISR) and combat missions. These video sensors provide a considerable amount of data for exploitation, suitable for various types of assisted and autonomous processing, including target recognition, tracking, contextual scene analysis, aimpoint generation as well as forensic analysis, behavioral characteristics and inference. In general, sensor model-based methods provide the most accurate approach to georegistration. However, smaller UAVs may not have well calibrated sensors or their existing sensor models and sensor pointing directions may not be available. These limitations make associating accurate positioning information with the video frames problematic using sensor model-based techniques.

ISL is developing a capability to automatically produce accurate geopositioning information from UAV collected video in real time using advanced image registration techniques. Since this approach does not require a sensor model, it is particularly well suited for applications in which UAV video data has poor or unknown sensor metadata. A high-accuracy location estimate for each pixel in the image can be generated quickly by registration with a geo-spatial reference database. ISL has developed the modified log-polar transformation (LPT) registration technique to perform this registration with high-precision and modest computational cost. This advanced image registration technique can also be applied to detection of moving targets in video data and non-GPS navigation.