UHF MILSATCOM channel availability is limited by sporadic narrowband interference. When frequency separation between the interferer and signal-of-interest is insufficient, use of conventional fixed-frequency filtering will result in unacceptable distortion to the signal-of-interest. In this Phase… More

The airborne collection environment will encounter a large degree of its operations in an environment predominated by co-channel interference. While no currently available product or algorithm is capable of mitigating all sources of co-channel interference, existing techniques may be used either… More

UHF MILSATCOM channel availability is limited by sporadic narrowband interference. When frequency separation between the interferer and signal-of-interest is insufficient, use of conventional fixed-frequency filtering will result in unacceptable distortion to the signal-of-interest. In this Phase II… More

Cosite interference, or self-jamming, occurs whenever operation of transmitting RF equipment interferers with operation of co-located receiving equipment. Ordinarily, such interference is avoided by design, through use of frequency separation, temporal separation or spatial separation. Oftentimes,… More

The Improved Web-Based Mapping (IWM) System will significantly improve on current AJAX-based techniques for browser-based web mapping. Using the latest emerging technologies in the web development field, GIRD Systems will develop a rich user interface that operates without requiring software or… More

Unlike a wired network, all communications in a wireless network is broadcast by nature, therefore prone to malicious attacks. Wireless information assurance (IA) is therefore of paramount importance to the healthy development of wireless technologies. Various forms of wireless information… More

The signals intelligence (SIGINT) mission has taken on a new importance in the electronic warfare (EW) domain as improvised explosive devices (IEDs) are often enabled by consumer-grade electronic devices. Detecting, Identifying and Geo-locating (DIG) these devices before they can cause harm is… More

Intermodulation refers to a wide-spread problem in RF power amplifiers. When an amplifier amplifies multiple frequency-separated signals simultaneously, or one signal with more than one frequency content, it also mixes different frequency contents of these signals such that two frequency contents… More

Signal direction of arrival (DOA) estimation is a classical problem that exists in a wide range of military and civilian applications. There are many classical high-resolution DOA estimation algorithms that can be used to estimate the DOAs of ideal narrowband sources with known center frequencies. … More

Very Low Frequency (VLF) and Low Frequency (LF) reception suffers from interference of atmospheric noise caused by lightning, which occurs year round. In this proposal we investigate innovative mitigation methods that have the potential of suppressing atmospheric noise in LF/VLF communications.… More

The need for accurate satellite channel models and their implementation as a simulation tool is addressed in this proposal. Improved mathematical models are proposed which provide the flexibility to model diverse environments, and to do so more accurately than current models, for both stationary… More

Navy SIGINT systems are required to receive low level signals in the HF, VHF and UHF frequency bands. The SINCGARS (30-88 MHz) band occupies part of the VHF frequency band where signal reception is required. U.S. Navy ships will have from 2 to 8 SINCGARS transmitters installed, which are used to… More

Cosite interference, or self-jamming, occurs whenever operation of transmitting RF equipment interferers with operation of co-located receiving equipment. Ordinarily, such interference is avoided by design, through use of frequency separation, temporal separation or spatial separation. Oftentimes,… More

Despite recent and ongoing improvements to the GPS infrastructure, GPS-aided positioning is often jeopardized by both intentional and incidental jammers. GPS services are not available in many desired areas of operation, including indoors, under foliage and in urban canyons. A fall-back capability… More

The importance of wireless network security cannot be overemphasized. Unlike a wired network, all communications in a wireless network are broadcast by nature, meaning that anyone in the transmission range can either receive the signals not intended for him/her, or inject unauthorized signals into… More

Signal direction of arrival (DOA) estimation is a classical problem that exists in a wide range of military applications such as radar, sonar, COMINT, as well as civilian applications such as emergency/disaster response, search and rescue, and the cellular telephone industry. In many of these… More

ELINT systems are often limited in bandwidth because the Nyquist criterion restricts the sampled bandwidth to one half of the maximum sampling rate of the A/D converter. While A/D converter technology has improved over the last several years, it is still not sufficient for many wideband… More

Electromagnetic (EM) signal source direction finding (DF) or direction of arrival (DOA) estimation is a classical problem that exists in a wide range of applications. Wideband signals are becoming more prevalent nowadays. Therefore the need for wideband DOA estimation is becoming more urgent.… More

Non-linear effects in amplifiers for communications systems such as intermodulation products can reduce efficiency and introduce RF interference into other bands. GIRD Systems herein proposes a method of amplifier linearization to mitigate the nonlinear effects. The hardware architecture is designed… More

Chaotic communication has attracted much interest due to its potential for secure communications and its potential for high data rates. In this proposal, GIRD Systems proposes to perform a feasibility study to evaluate, develop, and finally implement (in Phase II) some promising chaotic modulation… More

Time to first fix (TTFF), i.e., the initial acquisition of GPS signals can be quite large when the GPS UE has a degraded timing solution or during a cold-start, when the UE has absolutely no knowledge of time or initial position. In addition, the Coarse Acquisition (C/A) code may not always be… More

The proposed Phase II effort is focused on implementing a hardware prototype of the core polarization wideband direction finding technology developed in Phase I. The developed DF algorithm is capable of high resolution DOA and polarization estimation using an antenna array having polarization… More

ELINT systems are often limited in bandwidth because the Nyquist criterion restricts the sampled bandwidth to one half of the maximum sampling rate of the A/D converter. While A/D converter technology has improved over the last several years, it is still not sufficient for many wideband… More

Installation of a counter IED jammer system on each individual Army vehicle has caused electromagnetic interference between the jammer and friendly communication systems. A fundamental enabling technology called active interference cancellation, which enables simultaneous jamming and communication… More

Under realistic mobile radio link conditions involving ground operation with multipath, or with an extended range, OFDM modulation efficiency quickly decreases. In this SBIR program, GIRD Systems will develop methods by which the communication range of links in OFDM-based mesh networks can be… More

In this effort GIRD Systems proposes to develop an innovative ultra wideband radar EW receiver. The receiver can operate in very dense RF environments, and has the potential of meeting the high POI, large instantaneous RF bandwidth, and high dynamic range requirements. Phase I effort will develop a… More

We propose the development of an architecture for cognitive radio networks (CRN) to provide robust operation in jamming environments. The cold re-start problem is addressed through an innovative signaling framework, and an adaptive transmission approach is applied for mitigating various levels of… More

Interference is one of the major impediments to Satellite Communications (SATCOM). When strong interference is inside SATCOM channels, signals may be corrupted so that mission critical communications via satellite are disrupted. In this proposal GIRD Systems proposes innovative excision algorithms… More

The Navy"s fleet relies heavily on UHF SATCOM for communications in Navy"s worldwide operations. Narrowband interference is a crippling factor in many UHF SATCOM channels. When even a single channel is rendered unusable by interference, many users are potentially affected, owing to the… More

ABSTRACT: High precision and low cost test data acquisition and analysis systems are of wide interest in both military and commercial circles today. These systems depend on accurate time or clock synchronization across the entire system in order to correlate individual data samples across multiple… More

For decades, High Frequency (HF) communications have been an important, in some cases the only, way of providing long distance communication. For most of that time, both voice and data communications in the HF radio bands (2 30 MHz) have been restricted to channel bandwidths no wider than 3 kHz.… More

UHF SATCOM is a critical piece of the Navy"s worldwide communications operations. When in-band interference corrupts one or more channels, the ability to this system can be limited. GIRD Systems proposes the development of a digital signal processing system that removes interference between an… More

In an effort to facilitate and further expedite the integration of the JTRS MUOS waveform to a large diversity of hardware platforms, GIRD Systems seeks to define and develop a methodology, including necessary tools and artifacts, needed to assess and improve the waveform portability effort. The… More