摘要 :
The unique characteristics of bistatic radar operation on the performance of airborne/spaceborne moving target indicator (MTI) radars that use space-time adaptive processing (STAP) are discussed. It has been shown that monostatic ...
展开
The unique characteristics of bistatic radar operation on the performance of airborne/spaceborne moving target indicator (MTI) radars that use space-time adaptive processing (STAP) are discussed. It has been shown that monostatic STAP radar has the following properties. 1) For a horizontal flight path and a planar Earth the curves of constant clutter Doppler (isodops) are hyperbolas. 2) For a sidelooking antenna geometry the clutter Doppler is range independent. 3) Clutter trajectories in the cosφ-F plane (F=normalized Doppler) are in general ellipses (or straight lines for a sidelooking array). We demonstrate that these well-known properties are distorted by the displacement between transmitter and receiver in a bistatic configuration. It is shown that even for the sidelooking array geometry the clutter Doppler is range-dependent which requires adaptation of the STAP processor for each individual range gate. Conclusions for the design of STAP processors are drawn
收起
摘要 :
The unique characteristics of bistatic radar operation on the performance of airborne/spaceborne moving target indicator (MTI) radars that use space-time adaptive processing (STAP) are discussed. It has been shown that monostatic ...
展开
The unique characteristics of bistatic radar operation on the performance of airborne/spaceborne moving target indicator (MTI) radars that use space-time adaptive processing (STAP) are discussed. It has been shown that monostatic STAP radar has the following properties. 1) For a horizontal flight path and a planar Earth the curves of constant clutter Doppler (isodops) are hyperbolas. 2) For a sidelooking antenna geometry the clutter Doppler is range independent. 3) Clutter trajectories in the cos/spl phi/-F plane (F=normalized Doppler) are in general ellipses (or straight lines for a sidelooking array). We demonstrate that these well-known properties are distorted by the displacement between transmitter and receiver in a bistatic configuration. It is shown that even for the sidelooking array geometry the clutter Doppler is range-dependent which requires adaptation of the STAP processor for each individual range gate. Conclusions for the design of STAP processors are drawn.
收起
摘要 :
In matched field processing (MFP) the spatial characteristics of a dispersive wave field are exploited to estimate certain parameters of the acoustic field, such as source location or characteristics of the acoustic channel includ...
展开
In matched field processing (MFP) the spatial characteristics of a dispersive wave field are exploited to estimate certain parameters of the acoustic field, such as source location or characteristics of the acoustic channel including environmental parameters. In airborne MTI (AMTI) radar, interfering echoes (clutter) are Doppler colored due to the platform motion. Optimum clutter suppression requires space-time or space-frequency processing. Some thoughts concerning cross-fertilization between these two areas are put forward. In particular, the idea of space-time MFP is stressed. A processor for space-time power estimation is proposed.
收起
摘要 :
A long-term implantable photoplethysmographic sensor system is proposed. The system employs an elastic cuff which is directly wrapped around an arterial blood vessel. The optically transparent cuff is equipped with light emitting ...
展开
A long-term implantable photoplethysmographic sensor system is proposed. The system employs an elastic cuff which is directly wrapped around an arterial blood vessel. The optically transparent cuff is equipped with light emitting diodes and a photo transistor including the technology of pulse oximetry. The sensor will permit real-time, continuous monitoring of important vital parameters such as arterial blood oxygen saturation and pulse rate over a long-term period in vivo. We emphasize on the specific requirements for design and instrumentation of the implantable sensor and discuss first in vitro data acquired with that new photonics-based sensor.
收起
摘要 :
The detection of slowly moving targets by air- and spaceborne MTI radar is heavily degraded by the motion-induced Doppler spread of clutter returns. Space-time adaptive processing (STAP) can achieve optimum clutter rejection via i...
展开
The detection of slowly moving targets by air- and spaceborne MTI radar is heavily degraded by the motion-induced Doppler spread of clutter returns. Space-time adaptive processing (STAP) can achieve optimum clutter rejection via implicit platform motion compensation. The fundamentals and properties of STAP applied to air- and spaceborne MTI radar are summarised.
收起
摘要 :
Clutter returns received by an airborne radar exhibit a Doppler bandwidth which depends on the platform speed, beamwidth and wavelength. Echoes of slow targets may, therefore, be buried in the clutter band and are difficult to det...
展开
Clutter returns received by an airborne radar exhibit a Doppler bandwidth which depends on the platform speed, beamwidth and wavelength. Echoes of slow targets may, therefore, be buried in the clutter band and are difficult to detect. Perturbations of the flight path due to the flight dynamics of the aircraft and wind effects may cause further degradation of the MTI performance. It has been shown in earlier papers of the author that space-time FIR filters applied to the output signals of a linear array antenna can be used to compensate adaptively for the flight path component of the platform motion so that a large improvement in signal-to-clutter-plus-noise ratio (SCNR) can be obtained. Such filters are referred to as TASTE (techniques for airborne slow target extraction) methods. These ideas are extended to the compensation of transversal velocity components by means of a planar array with horizontal orientation. The influence of the system bandwidth is also investigated. The results obtained can be generalised to compensate for three-dimensional perturbations of the flight path without using an inertial navigation device.
收起
摘要 :
Recognition of convoys of ground vehicles and estimation of the cross-range convoy length component during tracking by radar is discussed in this study. Radar with multi-channel array antenna is assumed. Such antenna offers the po...
展开
Recognition of convoys of ground vehicles and estimation of the cross-range convoy length component during tracking by radar is discussed in this study. Radar with multi-channel array antenna is assumed. Such antenna offers the potential of spatial and space-time signal processing. For estimation of the cross-range length component generalised power estimators are used. In presence of ground clutter such techniques require an moving target indication (MTI) function including clutter suppression. In the case of moving radar space-time clutter suppression such as space-time adaptive processing (STAP) is required. It is shown that the direction of motion as well as the cross-range of the convoy can be retrieved from data obtained during tracking.
收起
摘要 :
Space-time adaptive processing achieves optimum clutter rejection for airborne radar. Several aspects of space-time adaptive processing in the design phase of an operational system are addressed: use of a realistic array antenna (...
展开
Space-time adaptive processing achieves optimum clutter rejection for airborne radar. Several aspects of space-time adaptive processing in the design phase of an operational system are addressed: use of a realistic array antenna (planar circular, 1204 elements); forward-looking arrangement; comparison with conventional temporal MTI processing; effect of tapering and impact of jamming. Results of this work contribute to the trilateral AMSAR project.
收起
摘要 :
Two applications of space-time adaptive processing are addressed: clutter rejection for ISAR by a moving radar, and jammer cancellation for broadband radar like SAR. It is shown that for both problems the space-time covariance mat...
展开
Two applications of space-time adaptive processing are addressed: clutter rejection for ISAR by a moving radar, and jammer cancellation for broadband radar like SAR. It is shown that for both problems the space-time covariance matrix has a similar form. The effect of space-time FIR filtering on the resolution capability of ISAR and SAR is analysed. It appears that distortions of the point spreading function mainly appear close to the clutter (or jammer) notches of the adaptive filter, i.e. in areas where the filter transfer function is not constant with Doppler (angle).
收起
