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Quantitative radar studies are an important component of studying the movements ofbirds. Whether a bird, at a certain distance from the radar, is detected or not dependson its size. The volume monitored by the radar is therefore different for birds of differentsizes. Consequently, an accurate quantification of bird movements recorded bysmall-scale radar requires an accurate determination of the monitored volume for theobjects in question, although this has tended to be ignored. Here, we demonstrate the importance of sensitivity settings for echo detection onthe estimated movement intensities of birds of different sizes. The amount of energyreflected from a bird and detected by the radar receiver (echo power) depends not only on the bird’s size and on the distance from the radar antenna, but also on the beamshape and the bird’s position within this beam. We propose a method to estimate thesize of a bird based on the wingbeat frequency, retrieved from the echo-signal, independentof the absolute echo power. The estimated bird-size allows calculation of sizespecificmonitored volumes, allowing accurate quantification of movement intensities.We further investigate the importance of applying size-specific monitored volumes toquantify avian movements instead of using echo counts. We also highlight the importance of accounting for size-specific monitored volumeof small scale radar systems, and the necessity of reporting technical information onradar parameters. Applying this framework will increase the quality and validity ofquantitative radar monitoring.

This paper presents a single antenna radar sensor with Ku-band radar transceiver IC realized in 0.13 μm CMOS processes. In the radar receiver, a sensitivity time control using a DC offset cancellation feedback loop is employed for constant SNR irrelevant on the distance. To reduce the direct coupled Tx signal to Rx in single antenna radar, stub tuned hybrid coupler is adopted instead of circulator. The measured distance is 8.2 m with horn antenna and metal plate target.

The effect of ship navigation radar signal processing has a great impact on the overall performance of the radar system. In this paper, the signal processing algorithm is studied. Firstly, the principle of radar azimuth and distance monitoring is introduced, then the pulse accumulation algorithm and median filtering algorithm are analyzed, and finally a sea clutter suppression algorithm based on sensitivity time control (STC) and a rain and snow clutter suppression algorithm based on constant false alarm rate are designed to improve the target monitoring performance of radar. In the test of the algorithm, the radar signal processing algorithm designed in this study has good precision as monitoring error of the target's azimuth and distance is controlled within 1%; and it also has a better suppression effect of sea clutter and rain and snow clutter, which can suppress the clutter well, improve the target clarity, and ensure the safe navigation of the ship. The experiment proves the effectiveness of the proposed algorithm and provides some theoretical basis for the better processing of radar signals, which is beneficial to improve the environment perception ability of ships in harsh environments and promote the further development of the navigation industry.

In this paper we are explosively the fundamental theory of radar system modules STC (sensitivity time control) or sea clutter and FTC (fast time constant) or rain clutter. The STC and FTC are commonly used to some clutter. The radar signal is widely used for weather forecast, air port traffic control, military and fire control. The system implements radar processing procedures in real time mode in FPGA (field programmable gate array). The FPGA device providing good performance of cheap platform for research and development. The compact structure of STC and FTC can Implementations of Xilinx FPGA using the generated VHDL code.

In this work, a complementary metal-oxide semiconductor (CMOS) based transceiver with a sensitivity time control antenna is successfully implemented for advanced traffic signal processing. The collected signals from the CMOS radar system are processed with optimization algorithms for vehicle-type classification and speed determination. The high recognition rate optimization algorithms are mainly based upon the information of short setup time and different environmental installation of each sensor. In the course of optimization, a video recognition module is further adopted as a supervisor of support vector machine and support vector regression. Compared with conventional circuit-based detector systems, the developed CMOS radar integrates submicron semiconductor devices and thus not only possesses low stand-by power but also is ready for production. In the meantime, the developed algorithm of this study simultaneously optimizes the vehicle-type classification and speed determination in a computationally cost-effective manner, which benefits real-time intelligent transportation systems.

The subsurface radar suffers from two typical problems, i.e., strong clutter from surface and severe wave attenuation in the underground. This paper presents a unique countermeasure to these problems using a polarimetric FM-CW radar and an equivalent sensitivity time control (STC) technique. The authors apply the polarimetric filtering principle to suppress surface clutter either in the Co-pol channel or in the X-pol channel of synthetic aperture radar, yielding to polarimetric enhanced target image. This technique works when the surface clutter and target have different polarization properties. Moreover, they use an equivalent STC technique specially suited for FM-CW radar for a deep object sounding to compensate wave attenuation within the ground. These techniques contribute to a significant improvement of the radar performance and the detection image contrast, although the detection of the target is in general a much more complicated topic. The field experiments were carried out to show the usefulness of the method. Some detection results are presented.

We developed an underwater three-dimensional (3-D) imaging sensor using a 532-nm laser. The sensor system combines a dome lens with coaxial optics to realize a wide-scanning angle of 120 deg (horizontal)×30 deg (vertical) while having a compact size of 25-cm diameter and 60-cm length. A detector sensitivity time control circuit and a time-to-digital converter are used to detect a small signal and suppress the unwanted backscattered signals due to marine snow. 3-D imaging of the seafloor with 20-m width and 60-m length was demonstrated in the sea around Ishigaki Island, Japan.

A modern coherent Antarctic radar depth sounder for probing the ice sheets of Antarctica and Greenland has been designed and developed by the University of Kansas. It was successfully tested during the austral summers of 1987 and 1988 at Downstream Β and Upstream B, Antarctica. Ground-based measurements were made with the radar in a mobile hut hauled by a Sno-cat in 1987 and in a Spryte vehicle in 1988.The coherent Antarctic radar depth sounder (CARDS) is an unfocussed synthetic-aperture chirp radar where the along-track resolution is improved by extensive coherent integration. Surface acoustic wave (SAW) devices are used to implement pulse expansion and compression. A common stable oscillator for the transmitter and the receiver establishes coherency. The system signal-to-noise ratio is enhanced by pulse compression and coherent integration. Antennas for the ground-based measurements are configured with an array of eight dipole elements, four active and four passive, the latter acting as reflectors. The aircraft antennas also consist of four active elements hung underneath the two wings. The wings serve as reflectors. A PC facilitates system control and data recording on a high-density recorder. Α-scope plots of selected records allow frequent field checks on system performance. More descriptive display facilities have been incorporated in the latest version of the system.The radar transmits 60 ns, 20 W peak power at 150 MHz. The number of coherent integrations is selectable up to 64 k. The system is capable of 5 m range resolution and 5 km range in ice. A programmable sensitivity time control (STC) increases the receiver dynamic range. System parameters such as pulse-repetition frequency, number of integrations, and display modes can be chosen during field operations by user-friendly software.This paper describes the design and field operations of the system. Some results of the 1987 operations at Downstream Β are presented.

A new short-pulse digital profiling radar system that operates at lower frequencies than most ice radars used in polar regions to date has been designed and built by the U.S. Geological Survey. The transmitter is an avalanche transistor pulser which drives a resistively loaded dipole transmitting antenna. A similar, but separate antenna is connected to the receiver. The receiver has adjustable sensitivity time control (STC) of as much as 60 dB to compensate for attenuation and geometric spreading factors. A fiber-optic cable is used to transmit both control signals and data. The data-acquisition and display system incorporates very high-speed digitizing and signal averaging, real-time profile display, and data storage on standard computer nine-track magnetic tape.The system was successfully used on Ice Stream B in West Antarctica at centre frequencies of 1, 2, 4, 8, and 12.5 MHz. Bottom-return signal-to-noise ratios of more than 40 dB were obtained at 2 MHz through 800 m of ice. Convoluted internal surfaces not related to present bottom topography were resolved within the ice streams and anomalous strong reflections or “bright spots” were identified near the base of the ice. At present, there is no satisfactory glaciological explanation for either of these observations.

This paper develops a method to calculate the effects of sensitivity time control (STC) on interference, experienced by one radar, caused by another radar. The probability density function (PDF) of STC attenuation is determined by, and is related to the overall probability distribution that determines the probability of interference. This method is consistent with, and complementary to the method of calculating the effects of antenna-to-antenna coupling between the radars. >

The need for increased dynamic range at the input to the radar digital signal processor has increased steadily over the last decade or so. This has been the result of lower expected radar cross sections, the need for better clutter suppression, and the desire to operate without sensitivity time control (STC) in some radar applications. The analog-to-digital converter (ADC) is the most significant bottleneck in achieving this needed dynamic range (DR). An approach for improving the effective DR utilizing multiple ADC is described. The ADC are arranged in parallel channels with different gains and the approach is referred to as a "stacked A-to-D converter", or "stacked ADC". Detailed results are presented for an experimental brassboard system assembled to demonstrate and evaluate the concept.

Two high-dynamic-range receiver subsystems for use in airborne radar fire control and tracking applications are described. The X-band dual-channel monopulse tracking receiver operates at 9.36+or-0.290 GHz with a 6-dB noise figure and a linear instantaneous dynamic range of 42 dB. A total of 80 dB of RF and IF gain control is programmable with less than +or-15 degrees phase and +or-1 dB amplitude tracking errors. The Doppler radar receiver operates at 9.3+or-0.15 GHz and has a 4.6-dB noise figure with >or=80 dB of instantaneous dynamic range. An 18-dB sensitivity time control (STC) circuit and a 60-dB dump attenuator allow close-in target reception. >