A Radar Course at Undergraduate Level: An Approach to Systems Engineering

IEEE TRANSACTIONS ON EDUCATION, VOL. 46, NO. 4, NOVEMBER 2003 497 A Radar Course at Undergraduate Level: An Approach to Systems Engineering Adriano J. Camps, Senior Member, IEEE Abstract This paper describes the undergraduate radar course taught at the Escola Universitària Politècnica del Baix Llobregat (EUPBL) of the Universitat Politècnica de Catalunya (UPC), Barcelona, Spain. At present, the EUPBL offers a three-year degree in Technical Telecommunications Engineering. This paper briefly describes the EUPBL, the organization of the degree program, the structure of the radar course, the evaluation methods, and two practical exercises on a sonar demonstrator and a global positioning system kit. Index Terms Demonstration kit, radar, remote sensing, systems engineering, undergraduate course. I. INTRODUCTION THE ORGANIZATION of the degrees in Engineering in Spain consists of two levels. The first level in Telecommunications Engineering is a two-and-a-half-year-long program of studies plus a four-to-six month final project, leading to the degree in Technical Telecommunications Engineering. The second level is also a two-and-a-half-year-long program plus a final project that usually takes between six and 12 months, leading to the degree in Telecommunications Engineering. At the Universitat Politècnica de Catalunya (UPC), Barcelona, Spain, these degrees are offered by the Escola Universitària Politècnica del Baix Llobregat (EUPBL) and by the Escola Tècnica Superior d Enginyeria de Telecommunicació de Barcelona (ETSETB), respectively. The author lectures in both schools, with an average teaching load of 7 h/week. Since 1964, at the ETSETB, specific courses on Radar, Radio Navigation Systems, and Remote Sensing have usually been reserved for graduate students or for students in the last academic year of Telecommunications Engineering. However, in 1994, the EUPBL decided to offer a general undergraduate radar course for two reasons. First, a growing number of applications make use of these technologies. Second, from the academic point of view, the subject of radar is very well suited to make students think at a system level. It integrates knowledge acquired in other courses, such as antenna theory, wave propagation, microwave, and electronic circuits, signal processing, and mathematics. Manuscript received March 9, 2001; revised October 30, 2002. This work was supported in part by the Escola Universitària Politècnica del Baix Llobregat (EUPBL) from the years 1997 and 1998 for implementation of the sonar and GPS kits. The author is with the Department of Signal Theory and Communications, Polytechnic University of Catalonia, 08034 Barcelona, Spain (e-mail: camps@tsc.upc.es). Digital Object Identifier 10.1109/TE.2003.816065 The EUPBL and the curriculum is briefly described in Section II. Section III describes the radar course itself, with a special emphasis on the way it is taught. In particular, this section describes practical exercises with a sonar operated in pulsed-mode and a global positioning system (GPS) laptop-based application. Finally, Section IV summarizes the main conclusions. II. THE CURRICULUM AT EUPBL Classes started at the EUPBL [1] in the academic year 1991/1992, with the degree in Technical Telecommunications Engineering Telecommunication Systems. The EUPBL pioneered a new curriculum based on continuous evaluation and a semester organization at a time all studies were organized in a year basis. The studies are organized in three academic years of two semesters each, named 1A, 1B, 2A, 2B, 3A, and 3B [2], with a total of 237 credits, 1 from which a) 202.5 correspond to core courses (105 for theory, 85.5 for practical training, and 12 English credits, which may be obtained elsewhere); b) 10.5 credits correspond to elective courses within the school; and c) 24 credits, which are elective courses that may be obtained at other schools at UPC. Core courses are usually split into theoretical and practical classes, although some are only taught in the laboratory. Students are required to pass two screening semesters to be allowed to register for the next courses; otherwise, they cannot proceed with their studies at the EUPBL. During the three years, students are individually guided by a tutor who counsels them in course selection, internships in companies, and other academic matters. III. THE RADIO RANGING AND RADIO NAVIGATION COURSE The Radio Ranging and Radio Navigation course was conceived as a course that forces students to think at a system level and to integrate the concepts they have learned in other courses. The course is taken as an elective by students of the EUPBL in the 3A or 3B semesters or by students from other Schools of Engineering within the UPC. A single full-time faculty member is responsible for lectures and practical sessions. The original scope of the course was broadened to include microwave remote sensing and laser techniques. In many cases, this change simplified the depth of the mathematical analysis, while preserving the main results. 1 1 credit = 10 class h. In a 15-week semester, 1.5 credits = 1 class h=week. 0018-9359/03$17.00 2003 IEEE

498 IEEE TRANSACTIONS ON EDUCATION, VOL. 46, NO. 4, NOVEMBER 2003 TABLE I ORGANIZATION OF THE COURSE ON RADAR AND RADIO POSITIONING, 4.5 LECTURE H PER WEEK (THEORY + PRACTICE) A. Organization and Evaluation of the Course The contents are organized in two parts: Part I Fundamentals, and Part II Applications, which cover about two thirds and one third of the 15-week semester, respectively. Table I describes the schedule, topics, and goals of each session and references the recommended bibliography. The first week is devoted to the presentation of the course and the review of basic concepts. In unit 1, the radar range equation is derived from two link-budget equations. The next three units analyze the concept and performance of different types of radars: pulsed radars, monopulse radars, and FM/CW radars. Finally, the next two units in Part I are devoted to the application of some techniques that students have learned in the context of communications: detection of signals buried in noise, matched filter, and pulse compression techniques. The organization of Part II Applications is somewhat different. Classes are offered as seminars, and the use of graphical material is dominant. Four different systems are treated: microwave radiometers, positioning systems (with special emphasis on GPS), imaging radars (SAR), and lidars (laser radars ). These four systems help students to broaden their perspective on the applications of radar systems, and the Electromagnetics and Photonics Group [7] of the Department of Signal Theory and Communications [8] has implemented such real systems. Students take a lab tour and demo at the ETSETB facilities so that they can see how these instruments 2 work and can talk to the faculty members who designed them. 2 Instruments presented: X.band polarimetric radiometer, bistatic radar, antenna and radar cross-section (RCS) anechoic chambers, scatterometer, and atmospheric and Doppler lidars [9]. Evaluation is based on the following criteria. Part I is evaluated with two exams, 3 covering units 1 to 4 and 5 to 7, respectively. Each exam consists of ten short theoretical questions to be solved in 1 h. Part II is evaluated based on a 20-page paper synthesizing bibliographic research, with a weight of 26% (progress and final reports). A list of proposed topics is provided, although students can propose their own topic. Work is performed in groups of three students. Credit for individual students is given based on an oral presentation in which all three group members must participate. Six collections of problems (units 2 to 7) and one collect of practical work based on the processing of data collected by one of the demonstration kits described hereafter are assigned for homework, with a weight of 15% for each one. Subjective evaluation, with a weight of 10%, comes from the professor s perception on each student s dedication, interest, and attendance to class. On the average, the number of students is approximately 35. The American equivalent grades are usually distributed as follows: 5 A, 15 B, 10 C, 4 D, and only 1 F. During the years 1997 and 1998, two academic demonstration kits, which are described hereafter, have been developed: a sonar for demonstrating the basic radar concepts and a GPS PC-based application. These practical sessions take place in regular lecture hours at the end of units 3 and 9. 3 Each exam has a weight of 17%. EUPBL regulations require that the weight of each exam cannot exceed 20%.

CAMPS: RADAR COURSE AT UNDERGRADUATE LEVEL 499 (a) (b) (c) (d) (e) (f) Fig. 1. (a) SONAR demonstrator, including parabolic reflector with ultrasound transducers. (b) Transmitter block diagram. (c) Amplitude detector block diagram. (d) Doppler detector block diagram. (e) Received signal for a stationary target. (f) Received signal for a target approaching the antenna at 2 m/s. The direct signal is collected by the receiver while it is being transmitted. B. Sonar Kit The objectives of the sonar kit are a practical understanding of: a) the relationship between range resolution and pulse width/receiving bandwidth, b) the relationship between the pulse repetition period and the maximum unambiguous range, c) the effect of the filter s bandwidth in range resolution and noise level, and d) the capability of sorting stationary from moving targets by operating the sonar as a MTI (moving target indicator) by subtracting one pulse

500 IEEE TRANSACTIONS ON EDUCATION, VOL. 46, NO. 4, NOVEMBER 2003 (a) (b) Fig. 2. (a) Main screen: Geographic representation of a track from the Campus Nord of UPC in Barcelona, to the EUPBL in Sant Just Desvern. (b) Zoom of Fig. 2(a) (in this case, errors are on the order 10 15 m). from the next one, when the pulse repetition period is varied [ in Fig. 1(b)]. In addition, it helps to explain the problems associated with synchronization, jitter, etc., that inevitably happen in a simple system like this one. The sonar kit is operated in pulse mode, with adjustable transmitted power, pulsewidth, receiving bandwidth, pulse repetition period ( ), alternating period between and, and a number of sampling bits (8 or 16). The kit s main parameters are: 40-KHz center frequency, range resolution 10 cm, maximum unambiguous range 30 m, and 360 azimuth scan. Fig. 1(a) shows a close-up of the system. The transmitter and receiver are displaced from the focus of the parabolic reflector so as to enlarge the beamwidth; the box in the mast holding the reflector is the low-noise preamplifier. The other two boxes contain the mechanical gears and motors (top) and the transmitter/signal acquisition circuitry (bottom). The transmitter uses a commercial 40-KHz piezo-crystal oscillator modulated by pulses of variable period and width [Fig. 1(b)]. Receiver outputs are connected to a position [Fig. 1(c)] and a Doppler detector [Fig. 1(d)]. Signals are sampled at 44 KHz using a PC sound-blaster card. Fig. 1(e) shows an example of the response to a stationary target, and Fig. 1(f) the response of the Doppler detector for an approaching target at about 2 m/s. Two-dimensional pulse plane indicator (PPI) representations are obtained by rotating the antenna (controlled by the PC). C. GPS Kit The objectives of the GPS kit are a practical assessment of: a) basic GPS performance in terms of initialization time, root mean square (rms) errors and drifts in,, and coordinates; b) positioning jumps because of changes in the satellite constellation used to compute the position; and c) reduced positioning capabilities under limited satellite visibility (blocking satellites by buildings wall). The Differential GPS is not available in this kit, but it is presented to students. The GPS kit is a standard MATLAB-based application (no toolboxes required) that communicates from a laptop computer to a Garmin 12XL GPS receiver [10] through the serial port. Once the connection has been established, the system presents in a figure the 10-m resolution map corresponding to the actual

CAMPS: RADAR COURSE AT UNDERGRADUATE LEVEL 501 position and displays a cross on it. For the entire region of Catalonia, Spain, 10-m resolution maps are available in memory. Other parameters are displayed on the right side. On the left side, a number of functions perform geometric operations: determination of distances and polygonal areas and positioning of a given pixel. A second screen displays system parameters: a polar representation of visible satellites and their signal-to-noise ratio, the latitude, longitude, speed, and direction. Fig. 2(a) shows the main screen of the program with a sample track between the ETSETB and the EUPBL, and Fig. 2(b) shows a zoom while making a circle (absolute positioning errors are on the order of 10 15 m). IV. CONCLUSION This paper has presented the program of the studies leading to the degree in Technical Telecommunications Engineering at the EUPBL. The motivation of the Radio Ranging and Radio Navigation course at an undergraduate level has been discussed, as well as its structure, the evaluation, and two practical exercises. ACKNOWLEDGMENT The author would like to express his gratitude to students S. Fructuoso, X. Elizondo, and S. Gregorio who implemented these systems during their final projects. The author also would like to express his gratitude to the reviewers for the quality of their comments and review. REFERENCES [1] (2002, Sept.). EUPBL. [Online]. Available: http://www-eupbl.upc.es/ [2] (2002, Sept.). EUPBL. [Online]. Available: http://www-eupbl.upc.es/ cat/estudis/plaest/plaest_public.htm [3] M. I. Skolnnik, Introduction to Radar Systems. New York: McGraw- Hill, 2000. [4] F. T. Ulaby, R. K. Moore, and A. K. Fung, Microwave Remote Sensing: Active and Passive. Norwood, MA: Artech House, 1981 and 1982, vol. 1 and 2. [5] E. D. Kaplan, Understanding GPS: Principles and Applications. Norwood, MA: Artech House, 1996. [6] R. M. Measures, Laser Remote Sensing: Fundamentals and Applications. Melbourne, FL: Krieger, 1992. [7] (2002, September 5th). [Online]. Available: http://www-tsc.upc.es/eef/ [8] (2002, Sept.). Dept. of Signal Theory and Communications. [Online]. Available: http://www-tsc.upc.es/ [9] A. Camps, Remote sensing activities at the Polytechnic University of Catalonia, Spain, Geosci. Remote Sensing Newslett., no. 110, pp. 16 21, June 1999. [10] (2002, Sept.). Garmin. [Online]. Available: http://www.garmin.com/ products/gps12xl/ [11] J. Elizondo, Diseño de un Sonar Experimental Para Aplicaciones Docentes Implementación del Software de Adquisición y Procesado, Final Project, EUPBL, Polytechnic University of Catalonia, Barcelona, Spain, 1998. [12] S. Fructuoso, Diseño e Implementación de un Prototipo Sónar Experimental Para Aplicaciones Docents, Final Project, EUPBL, Polytechnic University of Catalonia, Barcelona, Spain, 1998. Adriano J. Camps (S 91 A 97 M 00 SM 03) received the Telecommunications Engineer degree and Ph.D. degree in telecommunications engineering from the Polytechnic University of Catalonia, Barcelona, Spain, in 1992 and 1996, respectively. From 1991 to 1992, he received an Erasmus fellowship to study at the ENS des Télécommunications de Bretagne, Bretagne, France. In 1993, he joined the Electromagnetics and Photonics Engineering Group, Department of Signal Theory and Communications, Polytechnic University of Catalonia (UPC), as an Assistant Professor and has been an Associate Professor there since 1997. In 1999, he was on sabbatical at the Microwave Remote Sensing Laboratory, the University of Massachusetts, Amherst. His research interests are focused on active and passive microwave remote sensing, with special emphasis in aperture synthesis and interferometric radiometry (the European Space Agency s SMOS Earth Explorer mission). He is an Associate Editor of Radio Science. Dr. Camps received the second Spanish national prize of university studies in 1993; the INDRA award for the best Ph.D. in remote sensing in 1997; the UPC award for the best Ph.D. in 1999; together with the other members of the UPC remote sensing team, the First Duran Farell Award for Technological Research (60.000 euros) in 2000; and the City of Barcelona Award for Technological Research (8.000 euros) in 2001. In 2002, he received the Research Distinction of the Government of Catalonia for his contributions to passive microwave remote sensing. He is an Editor of the IEEE GRS Newsletter and President Founder of the Spanish Chapter of the IEEE Geoscience and Remote Sensing Society.