Yilmaz Kalkan

Target localization methods for frequency-only MIMO radar

In Multi Input-Multi Output (MIMO) radar, the target localization is possible by using only the frequencies of received signals instead of using whole data on the received signals for moving targets. As target is moving, received frequency will be shifted as doppler frequency. Received frequencies which are scattered from non-manouvering and constant speed target, can be written in two dimensional (2D) space with respect to the target coordinates. A cost function can be defined by the help of these frequencies, and than by using grid search, local minimum of this cost function can be found in (x, y) coordinates. In this work, a new target localization method is poroposed for frequency-only MIMO radar.

Frequency based target localization methods for MIMO radar

A new frequency based target localization method is proposed for MIMO radars which are widely separated. The performance of this new method is compared with other frequency based target localization methods. For target localization, time of arrival (TOA), angle of arrival (AOA) and frequency of arrival (FOA) informations can be used in cooperation. In general, TOA information is enough to localize a target. However, when the time resolution of the transmitted signals is not enough or good,i.e.; unmodulated CW radar, we can not rely on the TOA information to localize the target. On the other hand, if the frequency resolution of the transmitted signals is enough, only received frequencies can be used for finding the position of the target. Localization of a moving, non-maneuvering target is possible by using Doppler-shift measurements in MIMO radar systems. This is a nonlinear problem and it can be solved by grid searching. After defining suitable cost function for grid search, desired area can be searched grid by grid to find the position of the target in 2D space.

Target localization and velocity estimation methods for frequency-only MIMO Radars

Target localization and the velocity estimation methods are proposed for frequency-only MIMO Radar with widely separated stations. For the target localization, time of arrival (TOA), angle of arrival (AOA) and frequency of arrival (FOA) informations can be used in cooperation. When the time resolution of the transmitted signals is not enough or good, i.e.; unmodulated CW radar, we can not rely on the TOA information to localize the target. On the other hand, if the frequency resolution of the transmitted signals is enough, only received frequencies can be used for finding the position of the target. Localization of a moving, non-maneuvering target is possible by using the Doppler-shift measurements in MIMO radar systems. This is a nonlinear problem and it can be solved by grid searching. After defining suitable cost function for the grid search, the desired area can be searched grid by grid to find the position of the target in 2D space. After target positioning is achieved, velocity of the target can be found by using the predefined cost function.

Frequency-based target localization methods for widely separated MIMO radar: FREQUENCY-BASED LOCALIZATION METHODS

Frequency-based localization methods are widely used to find emitter locations. Several techniques are described in the literature for emitter localization based on Doppler frequency shifts. These techniques can be used efficiently for emitter localization by using narrowband signals. Although these methods are simple and efficient, the application to the radar systems for target localization is very limited. In this paper, a new low-complexity target localization method, Target Localization via Doppler Frequencies (TLDF), for Doppler-only Multi-Input, Multi-Output (MIMO) radar with widely separated stations is described. By using widely separated MIMO radars with unmodulated continuous wave signals, the received frequencies and the Doppler shifts can be estimated efficiently. The position and the velocity of the target can be found from these estimated frequencies by a search in the position space. As the Doppler frequency is estimated efficiently, not only the target velocity but also the direction of the target is estimated accurately with the TLDF method. The Cramer-Rao Bounds (CRB) are calculated for the target velocity and the target position estimations in two-dimensional space. In simulations, the proposed method is compared with the iso-Doppler curves-based traditional method and with the CRB for different geometries. The performance of the proposed method is not affected from the target amplitude fluctuations because of its frequency-based nature. Finally, the comparison between the frequency-only MIMO radar and the pulsed monostatic radar is investigated, and the simplicity and the efficiency of the proposed method are demonstrated.

An initial data association method by using doppler frequency for multi target

The association of the received signals with exact targets is the most basic and the vital problem in the multitarget applications. In the literature, this problem is known as data association. In the multitarget case, after the association of the received signal with the correct targets, these associated signals can be used in many applications such as target localization and target tracking. The errors in data association is caused to increase the error in the following steps which use the wrong associated signals. In this paper, a new initial data association method is proposed for the frequency-only systems in multitarget case. In general, the time, frequency and phase informations of the received signal are used for data association. If the time resolution of the used signals is not good or enough (such as in unmodulated continuous wave (CW) signals), in this case instead of time information, using the frequency information is better.

Cramer rao bound for target localization with MIMO radar

For target localization with radar, time of arrival (TOA), angle of arrival (AOA) and frequency of arrival (FOA) informations can be used in cooperation. In general, TOA information is enough to localize a target. Moreover, if the target velocity should be estimated, the target velocity is able to estimated by using doppler frequency. In this paper, the Cramer-Rao Bound (CRB) is shown for Multi Input, Multi Output (MIMO) radar with widely separated antennas case. CRBs are compared for different targets and transmitter-receiver configurations.

Velocity estimation methods for frequency-only MIMO radar

After finding position in 2D space, target velocity can be estimated by using found target position information and used cost function. In this paper, velocity estimation is achieved for pre-proposed target localization methods. For target localization, time of arrival (TOA), angle of arrival (AOA) and frequency of arrival (FOA) informations can be used in cooperation. When the time resolution of the transmitted signals is not enough or good,i.e.; unmodulated CW radar, we can not rely on the TOA information to localize the target. On the other hand, if the frequency resolution of the transmitted signals is enough, only received frequencies can be used for finding the position of the target. Localization of a moving, non-maneuvering target is possible by using Doppler-shift measurements in MIMO radar systems. This is a nonlinear problem and it can be solved by grid searching. After defining suitable cost function for grid search, desired area can be searched grid by grid to find the position of the target in 2D space. After target positioning is achieved, velocity of the target can be found by using predefined cost function.