Method of measuring doppler shift of moving targets using FMCW maritime radar

During the operation of an FMCW (frequency modulated continuous wave) maritime radar, the system transmits a continuous radio energy with a frequency modulated by a triangular or sawtooth-shaped signal. As a result, the frequency of the transmitted signal varies gradually with time. When the signal is reflected by an object, the received waveform will build up a delayed replica of the transmitted waveform, with the time delay as a measure of the target range. If the target is moving, the radar system will register a Doppler shift within the received signal. Compared to the frequency of the emitted signal, the received signal will show a higher frequency when the target is approaching and a lower frequency when the target is moving away from the radar location. Thus, the total Doppler shift may result from the superposition of both source and observer motions. Specifically, the amount of Doppler shift is directly proportional to the radial speed of the target. The Doppler shift can be determined after performing the range Fourier transform (range FFT) first. For a target of interest, we can repeat the range FFT until we have enough data to perform the second level of FFT. The result of this second FFT is a two dimensional complex valued matrix, whose spectral peak corresponds to the Doppler shift of the moving target. This method is known as Doppler FFT. Some results of the measurement of target speed using this method are presented in this paper

Development of GIS-based traffic simulation on the Jakarta’s highway

One serious problem in Jakarta megacity is the daily traffic jam. Recently, according to the ever increasing amount of newly registered vehicles in Jakarta, the time interval needed to across some districts in Jakarta tends to be longer. The main reason for the traffic jam is the condition in which the road capacity and the arrival rate of vehicles are not staying in balance. Well planned traffic rules can be used to control the traffic flow so that the overload condition should never happen. To assist in the planning of these traffic rules, a traffic simulator has been developed at the Center for Information and Communication Technology in BPPT. By integrating a GIS-based digital road map into the above traffic simulator, the visualization of the simulation results can be enhanced significantly. In this paper some of the simulation results which are performed on the Semanggi’s highway section are presented. Further, the capability of this software-tool to support the management of Jakarta’s highway will also be figured out

Software design to simulate FMCW radar signal: a case study of INDERA

Nowadays computer simulation plays a significant role in analyzing the radar signals. The research group at the Radar and Communication Systems (RCS) has developed a maritime radar, called INDERA, that works using the Frequency Modulated Continuous Wave (FMCW) technology. In line with the enhancement of the radar system we have alsodeveloped a software system that is able to be used for simulating the FMCW signal of radar INDERA. This work presents a design of the software that can be utilized not only to generate and analyze the FMCW radar signal, but also reconstruct the received radar signal onto a PPI (Plan Position Indicator) radar display. The software tool completed here will help us in analyzing the actual radar returns as well as the effects of surface scattering. The gained knowledge about the system characteristics in response to the abruptly changing situations is of great importance in extracting range information more easily

A method to determine radial speed of target from the FMCW radar signal

An established method to detect a target from the FMCW radar signal is implemented by using the method of range FFT (Fast Fourier Transform). By repeating the same procedure many times at a certain azimuth angle, it is possible to additionally compute the radial speed of the suspected target. This paper describes a method to determine the radial speed of target by extracting the phase data from the repeated range FFTs. To verify this method a series of computer simulations was conducted at our research group

Prototyping of a situation awareness system in the maritime surveillance

This paper discusses about the design of a Situation Awareness (SA) system to support vessel crews and control room operators in improving the decision making process. The architecture of the system is ontology based. The vessel crews and control room operators may face a loss of SA. They may have limited cognitive abilities which make it difficult to make a decision in a high stress level, short time availability and continuously evolving situation with incomplete information. In this work, we describe the application of Semantic Web Rule Language to represent corresponding knowledge in the maritime surveillance domain. The result of this research will demonstrate that an ontology based system can be used to remodel the information into a meaningful and valuable form to predict the future states of SA and improve the decision making process

Method and implementation to overlay radar image on the electronic chart

Electronic navigation becomes increasingly more common, particularly onboard commercial vessels. As one of important elements in the electronic navigation, the electronic chart has introduced a new level of performance to navigation such as Electronic Chart Display and Information System (ECDIS). As a completely new and interactive navigation information system, it has an undisputable capability for displaying all necessary chart and navigation-related information required for the safe operation of a vessel. However, despite its many advantages, an electronic chart does not present the dynamic real-time situation within a certain area or cell of the chart. To overcome this problem many ships are equipped with additional marine radars to monitor the real situation around their actual positions. Current trends show that there is an increasing demand to complement the electronic chart with available radar image. This paper describes a method and implementation to overlay radar image into the existing electronic chart