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A method of blended-polynomial curve fitting is employed to improve performance of time domain triggered inertial devices. In such devices, a spring-mass system is perturbed to oscillate sinusoidally. This sinusoidal motion of the mass (the carrier) is perturbed by the time varying motion caused by inertial accelerations (the signal). When the mass passes several predefined locations, a trigger accurately...
In this paper, we present a novel configuration of fixed distributed accelerometers combined with rotating accelerometers to infer the angular motion. Traditionally, fixed distributed accelerometers are configured to form a gyro-free inertial measurement unit (GF-IMU). The main advantage of using rotating accelerometer over fixed one is having direct measurements of the angular velocity. This configuration...
In this paper, we report a Sigma-Delta MEMS navigation grade accelerometer, which, to our knowledge, is the first reported MEMS accelerometer to reach navigation grade performances. This reported system encompasses a high stability and high shock resistance mechanical MEMS sensor, a 5th-order sigma-delta closed-loop electronic with digital loop filtering and high stability voltage reference.
A low-cost, high-yield, low-power gyro is presented from which five high performance variants are created by altering operating conditions. Flexible design of the gyro and the excellent dynamic range is explained. The paper details the high performance aspects of each variant with results from large population of dies. Measured results show a start up time less than 3ms and gyro output nonlinearity...
The Hemispherical Resonator Gyro (HRG) has proven itself to be an ultra-reliable technology for space application with over 20 million operation hours and 100% mission success. Northrop Grumman Navigation Systems Division is developing a terrestrial inertial navigation system, INS, based on the proven space technology that can be used for precision pointing applications. The Precision Pointing System...
Real-time gravity measurements provide an accurate, high-resolution snapshot of the local gravity signature. Information developed from the gravity signature can be a significant contributor to battle space situational awareness, providing enhanced knowledge of the local operating environment and of the location of each operational participant in that environment. The Strategic Systems Programs (SSP)...
In the VDFLL, the ranging errors will degrade the positioning accuracy as well as the tracking performances. In the paper, a new VDFLL tracking loop minimizing the ranging error by utilizing precise satellite orbit/clock and ionospheric products has been proposed. Unlike the conventional VDFLL, which treats all the measurement errors as zero-mean Gaussian noise with a high variance, the new VDFLL...
This paper presents an adaptive Kalman filter approach to track scintillating GNSS signals based on the empirical knowledge on the signal-to-noise ratio. The adaptive scheme to adjust the Kalman filter gain, changing in time-varying optimal manner for different C/N0 to have different equivalent noise bandwidths, is employed to track the signal in deep amplitude fades under strong ionospheric scintillations.
This paper presents the overall architecture, first test structure implementations, and measurement results of an integrated GNSS front-end based on intentional path overlay. The front-end ASIC supports simultaneous multiband, multi-system GNSS reception of GPS L5 / Galileo E5 / GLONASS G3 and GPS L1 / Galileo E1 / GLONASS G1 signals with up to 52MHz bandwidth while using only one common baseband...
It has been demonstrated that a position can be estimate in a GPS receiver using only sub millisecond code phase measurements, as opposed to complete pseudoranges. This technique is referred to as time free or snap shot positioning and requires a course estimate of time, an a-priori estimate of the receiver position and GPS satellite ephemeris information.
Body-worn microstrip patch antennas made from e-textile (Electro-Textile) materials were designed, built, and tested for the 1575 MHz (L1) and 1227 MHz (L2) Global Positioning System (GPS) frequencies. E-textiles, including fabrics and foam sheets, are flexible, lightweight, wearable, conformal, and the materials are low cost compared to conventional antenna materials. A variety of materials were...
This article focuses on the analysis of receivers that use a local replica that has a modulation that is different from that of the received signal. It aims at introducing the theoretical formulas associated to the performance in thermal noise of code tracking techniques based on the use of such non-standard local replicas. The proposed formulas allow understanding the implication of the choice of...
With the proposed of Comprehensive RDSS (CRDSS), it is in dire need of a new navigation receiver chip which comprises of Radio Navigation Satellite System (RNSS) and Radio Determination Satellite Service (RDSS) to obtain the benefits of CRDSS. The addition of RDSS (Beidou-I) capability can improve the reliability of position solutions. This paper shows the design of world's first CRDSS-compatible...
In this paper we present a practical system for indoor tracking that is low-cost, quick and simple to setup, and accurate. The system consists of three types of nodes, GPS referenced anchor nodes, static nodes placed at fixed locations within a building, and mobile tags that are attached to objects to be tracked. The network of anchor and static nodes must be setup to be globally rigid which allows...
A system that provides accurate and reliable location of Emergency Responders (ERs) in all types of environments presents multifaceted technological challenges. The system is intended to provide indoor/outdoor precision navigation, robust communications and real-time position updates on remote command display devices. Operational requirements include rapid and nonintrusive deployment, scalability...
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