Such remote measurement provides the opportunity of observing frequent, global sampling of soil moisture with large spatial resolution. The main advantage of microwave measurements is that they are not affected by cloud cover and variable solar illumination; however, the accuracy in soil moisture estimation is limited to regions with either bare soil or low to moderate amounts of vegetation [46].The two approaches used in microwave soil moisture measurement are active and passive [31]. In active methods a microwave pulse is transmitted and the backscattering from the object is received and compared with the signal sent to determine the backscattering coefficient. In passive methods, the brightness temperature is measured at microwave length.

Different portions of the microwave region of the electromagnetic spectrum known as bands are named by letters. Some of the most commonly used bands in Earth remote sensing are: K (18-27 GHZ), X (8-12 GHZ), C (4-8 GHZ), and L (1-2 GHZ) [31]. The best soil moisture information is provided at very low microwave frequencies (< 6GHZ) owing to the reduced atmospheric attenuation and greater vegetation penetration at lower wavelengths. Most Carfilzomib of the studies to d
Ship detection is a key requirement for monitoring traffic, fisheries and for associating ships with oil discharges.

Provision of a well designed maritime surveillance and control system capable of tracking ships is therefore essential and would be a vital interest to a variety of users ranging from local authorities to defence organizations, national and international.

The Vessel Monitoring System (VMS) that relies on a ship�Cborn component provides the authorities with a continuous monitoring of vessels’ location and movements in real time. However, many ships are not equipped with these systems, for example smaller fishery vessels and passenger boats do not have to apply with the existing directives (e.g. EC directive Drug_discovery 2002/59/EC). One has to resort to remote sensing using Earth Observation (EO) satellites in order to obtain information on these vessels.

In that sense, remote sensing is regarded as a technology to support the active system with passive measurements for non�Ccooperating ships, sensing of non�Charbour regions and monitoring purposes [1]. Space�Cbased imaging for ship detection and maritime traffic surveillance has often formed part of major research efforts in the fields of automatic target detection and recognition. Ship detection with satellite based on Synthetic Aperture Radar (SAR) was first demonstrated by the experimental SEASAT in 1978. With later first�Cgeneration satellites such as ERS�C1, JERS�C1, ERS�C2 the field has reached some maturity [2].