Problem statement: Finite Impulse Response (FIR) filters are widely used in various DSP applications. The design of digital FIR filters is a very basic problem in digital signal processing. A FIR filter with multiple operation capability is certainly very useful for any real-time filtering applications. This article presents a multipurpose FIR filter design modeled by the hardware description language VHDL for real-time filtering application. Approach: The VHDL has its concept of concurrency to cope with the parallelism of digital hardware. The novel feature is the capability of the design to accomplish up to 127variable filter order and an arbitrary filter frequency response. The coefficients are calculated by Hamming windowing technique. Basing on selection embedded in the design, the model is able to execute highpass, lowpass, bandstop and bandpass filtering operations. It is set at 8-bit signed data processing. To filter the input data in time domain, Linear Constant Coefficient Difference Equation (LCCDE) is used by the filter. Results: The design outputs are validated through simulation and compilation. The output results are also compared with the MATLAB implemented calculated output results to test the correctness that proves the effectiveness of the design. Conclusion: With the capability of filtering signal in real time mode utilizing arbitrary filter shape, the multipurpose filter proves to be versatile.
GPS (Global Positioning System) has become an integral part of a vehicle system which provides speed, time, direction etc besides the navigation data. Speed is one of the primary attributes of vehicle accident. Many lives could have been saved if emergency service could receive accident information timely. This paper proposes to detect an accident from the map matched position of a vehicle by utilizing the GPS speed data and map matching algorithm and send accident location to an Alert Service Center. The GPS provides speed and position in every 0.1 second. The position data will be used in the map matching algorithm to locate the vehicle on the road. The present speed will be compared with the previous speed in every 0.1 second through a Microcontroller Unit. Whenever the speed will be falling below the safe calculated threshold speed, the system will generate an accident situation. It will check the vehicle location from map matching module and generate an accident situation if the vehicle is found outside the road network. This will reduce the false accident detection drastically. The map matched accident location is then sent by utilizing the GSM network. The proposed system will save many accident victims with timely rescue.
Precise navigation is a vital need for many modern vehicular applications. The global positioning system (GPS) cannot provide continuous navigation information in urban areas. The widely used inertial navigation system (INS) can provide full vehicle state at high rates. However, the accuracy diverges quickly in low cost microelectromechanical systems (MEMS) based INS due to bias, drift, noise, and other errors. These errors can be corrected in a stationary state. But detecting stationary state is a challenging task. A novel stationary state detection technique from the variation of acceleration, heading, and pitch and roll of an attitude heading reference system (AHRS) built from the inertial measurement unit (IMU) sensors is proposed. Besides, the map matching (MM) algorithm detects the intersections where the vehicle is likely to stop. Combining these two results, the stationary state is detected with a smaller timing window of 3 s. A longer timing window of 5 s is used when the stationary state is detected only from the AHRS. The experimental results show that the stationary state is correctly identified and the position error is reduced to 90% and outperforms previously reported work. The proposed algorithm would help to reduce INS errors and enhance the performance of the navigation system.
Low power and low area Static Random Access Memory (SRAM) is essential for System on Chip (SoC) technology. Dual-Port (DP) SRAM greatly reduces the power consumption by full current-mode techniques for read/write operation and the area by using Single-Port (SP) cell. An 8 bit DP-SRAM is proposed in this study. Negative bit-line technique during write has been utilized for write-assist solutions. Negative voltage is generated on-chip using capacitive coupling. The proposed circuit design topology does not affect the read operation for bit interleaved architectures enabling high-speed operation. Designed in 0.18-&mum CMOS process, the area is only 1.2 times of the SP-SRAM and its power is 1.3 times of the SP-SRAM when the two ports simultaneously work at the same frequency. Simulation results and comparative study of the present scheme with state of-the art conventional schemes proposed in the literature for 45 nm CMOS technology show that the proposed scheme is superior in terms of process-variations impact, area overhead, timings and dynamic power consumption. The proposed negative bit-line technique can be used to improve the write ability of 6 T Single-Port (SP) as well as 8 T DP and other multiport SRAM cells.
Schmitt triggers are commonly used in communication and signal processing techniques to solve noise problem. A low voltage Schmitt trigger circuit with tunable hysteresis is proposed in this paper. For obtaining hysteresis under low voltage, a cross-coupled static inverter pair is used. By adjusting the symmetrical load operation, the hysteresis of the Schmitt trigger is varied. The cross-coupled inverter pair regenerative operation is controlled by it. Designed in 0.18 um CMOS process technology, the simulation results show that the proposed Schmitt trigger circuit's triggering voltage can be adjusted approximately 0.5 V to 1.2 V. The proposed design is suitable to be implemented in buffers, sub-threshold SRAMs, retinal focal plane sensors, wireless transponders and pulse width modulation circuits.
Radar and radio cannot pickup the low flying aircraft due to the limitation of radar horizon, which severely poses flight hazards. As such, tracking of the low altitude aircraft in real-time is a dire need. Global Navigation Satellite System (GNSS) receiver can provide position from the satellites. On the other hand, Global System for Mobile Communications (GSM) network, although works on the principle of line of sight, can transmit SMS or GPRS data at low altitude. This project proposes the real-time tracking of a low altitude flying rotor aircraft from GNSS position information transmitted over the GSM network. The problem of non-availability of GSM network for a particular network operator is solved by a dual SIM capable GSM modem. An algorithm will look for the signal strength and will transmit position information via the available stronger operator. The position information sent by the SMS/GPRS data will be received at the Control Center by another GSM modem. The position information will be displayed in a Google Map with the height, speed, time, etc. During a complete communication outage, the positioning data will be stored and transmitted during the availability of GSM network. Thus, the proposed system will be able to offer uninterrupted real time location information of a low flying aircraft.
Background/Objectives: Emergency Rescue Service could save many lives if the accident location could be intimated automatically. Accident location is generally acquired from Global Positioning System (GPS). However, location cannot be determined during GPS outage. Methods/Statistical Analysis: This paper proposes an accident detection system by determining the deceleration from the accelerometers of a low cost Micro Electro Mechanical Systems (MEMS) based Inertial Measurement Unit (IMU). The three axes accelerometers, gyroscopes and magnetometers data of the IMU were also programmed as Attitude Heading Reference System (AHRS) to determine the orientation and the position of the vehicle during a GPS outage. Errors in positional information were corrected by a Kalman filter during the availability of GPS. A communication module was programmed to send the accident data to the base station in real time. Findings: The test result showed the correct accident detection. The accident location module also determined the correct accident location in GPS outage condition and sent the accident location information to the base station. Application/Improvements: The system will save many lives by sending the automatic accident location to Emergency Rescue Service center. Keywords: Accident, GPS, IMU, Location, MEMS
Detection of enemy intrusion is vital in a war. Radar is an excellent tool for such detection. But due to the limitation of radar horizon and resource constraints, radar cannot cover an entire country, specially around the border for a low altitude flying objects. Visual reporting through observers has been in practice since World War. However, the conventional reporting system suffers from time delay, location ambiguity of the observer, limitation of communication medium, etc. Global System for Mobile Communications (GSM) is widely used nowadays and the network normally covers an entire country. The GSM based Android smartphones are mostly embedded with Global Positioning System (GPS) which can provide location information. This paper proposes a smartphone based flying object reporting system that uses the GSM network and GPS of the phone. An Android application was developed using Eclipse Android Development Tools (ADT). The time and position of the observer is acquired from GPS. User friendly options are included for easier reporting. Aircraft pictures are included for easier recognition. An evaluation of the application was done in a Samsung Galaxy J2 phone. The experimental result showed the correct functioning of the system. The system will allow the observer to recognize flying objects from the pictures and drastically reduce reporting time which will enhance the overall detection system and better preparation against enemy.
Charge pump circuit is widely used in many systems due to its low power consumption, high performance, small area and low current drivability. This paper presents a low-voltage, high performance charge pump circuit suitable for low-voltage applications such as EEPROM of Radio Frequency Identification (RFID) tag. Designed in 0.18-μm CMOS process, the proposed charge pump circuit is able to pump an input voltage of 1.8V to a measured output of 5.95V through 20MHz clock signal with each pumping capacitor of 0.1pF and smoothing capacitor of 0.1pF at the output. Simulation result shows that the proposed charged pump circuit offers higher pumping gain compared with the existing charge pump circuit. Besides the RFID tag, the charge pump circuit can also be used in other memory circuits.
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