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The Global Positioning System (GPS) is a satellite-based navigation network employing spread-spectrum techniques that is widely used for commercial and military applications. Although the large spreading gain of GPS allows for operation in very low signal-to-noise ratio environments, the received signals are vulnerable to various types of narrowband and wideband interference. In this paper, we propose a blind multi-component adaptive receiver based on the constant modulus (CM) array that cancels the high-power interference and recovers the GPS signal of interest without using a priori direction-of-arrival information or training data. The performance of the system at the output of each component is illustrated via computer simulations for an example signal scenario. Expressions for the output signal-to-interference-plus-noise ratio are also provided in order to investigate the steady-state properties of the system.

The Global Positioning System (GPS) is a one-way satellite communication system that is widely used for both civilian and military applications. Because of the relatively low power of the received signals, GPS is highly susceptible to a variety of intentional and unintentional interferers. In this paper we examine a multistage space-time adaptive-processor (STAP) that is used to improve the detection capability of a GPS receiver for a wide range of jamming scenarios. Depending on the type of interference, the stages incorporate structures such as a notch filter, a beamformer and a blind linear interference canceler. Computer simulations are provided to illustrate the performance of the multistage receiver for wideband and narrowband interferers.

The location determination technology (LDT) is one of the core techniques for the location-based services (LBS) which has various applications, including a mobile robot, for the modern wireless communication system. The time of arrival (TOA), which is a kind of LDTs based on the cellular network, estimates the location of the specific user or object using a trilateration method based on the received signals from three base stations (BS). The true location of a mobile station (MS) is determined based on an intersection point of three circles with the radius corresponding to the distance between each BS to MS. Since the TOA method estimates the distance between BS and MS using the number of time delay, these three circles should not generally meet at a point and the performance of the location detection should be degraded in this case. In order to overcome this problem, we propose the mobile location detection algorithm based on a line intersection of the TOA geometry. In the case of those three circles do not meet at a point; in general, there are six intersection points and three lines which connect two intersection points. In this paper, we determine an intersection point of three lines as the location of a MS. The computer simulation example is provided to illustrate the location detection performance of the proposed algorithm.

A key technology of the next generation robots is the ability to move with high speed, high precision and communication network control. We propose a vector control system by applying optical-EtherCAT to PMSM with two-axes. We describe configurations of hardware and software to vector control of PMSM with two-axis using an optical-EtherCAT and explain two phase coordinate transformations of the d-q-axis that is the basis of vector control with an optical EtherCAT. We also report results of vector current control, vector current and speed, and vector current and position control of PMSM with two-axes for proposed optical EtherCAT. We confirm that we achieved satisfactory control results due to vector control implemented with an optical EtherCAT.