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Azimuth Resolution

Azimuth Resolution

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Azimuth resolution refers to the ability of a radar or imaging system to distinguish between two objects in the horizontal plane, measured in the azimuth direction. It is determined by the system's antenna beamwidth and is critical for accurately resolving spatial details in radar images.
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Azimuth resolution refers to the ability of a radar or imaging system to distinguish between two objects in the horizontal plane, measured in the azimuth direction. It is determined by the system's antenna beamwidth and is critical for accurately resolving spatial details in radar images.
Stima della DNI in Antartide
by paolo Grigioni

2023

Sommario E' effettuata la stima dell'irradiazione solare diretta normale (DNI) giornaliera media mensile e annua, riferita alla regione che ospita la Stazione Mario Zucchelli, nella baia di Terra Nova (Antartide). Le stime si basano sulle... more
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3D Sar (Synthetic Aperture Radar) Imaging Simulation Using Java
by Erfansyah Ali

2022, TEKTRIKA - Jurnal Penelitian dan Pengembangan Telekomunikasi, Kendali, Komputer, Elektrik, dan Elektronika

One of methods in remote sensing is Synthetic Aperture Radar (SAR). When combined with Range DopplerAlgorithm (RDA) can produce smaller radar resolution only by using normal sized antenna placed atplatform. RDA is able to generate much... more
Figure 7. Simulation for Target B detection
Table 2. Hardware system used in simulation
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High-accuracy orientation survey in the Tiberius’ Cave near Sperlonga
by Giuseppe Veneziano

2022, Journal of Cultural Heritage

We exploit a very accurate electronic solar compass used for the first time in archaeology, to measure the orientation of structures at the Tiberius' Cave, which is adjacent to the Villa of the Roman emperor Tiberius located... more
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Il nuovo manuale degli osservatori geomagnetici italiani
by Domenico Di Mauro

2022

Il nostro pianeta è sede di un campo magnetico generato principalmente da correnti elettriche di origine interna alla Terra, che fluiscono nel nucleo esterno fluido, a cui si sovrappone un contributo dovuto a correnti elettriche presenti... more
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High resolution target localization using rotating linear array radar
by Mohammad Bilal Malik

2022, Multidimensional Systems and Signal Processing

The modern radar signal processing algorithms require high resolution, joint estimation of target parameters with lower computational complexity and processing time. The radar target parameter estimation includes estimation of range,... more
Figure 6.10: Sum for Azimuth Estimation
Figure 7.6: Data access from DDR for column FFT shows the remaining steps of row correlation.
Figure 7.12: Architecture for Direction finding above is shown in Figure 7.12
Table 6.2: Computational Complexities
Figure 4.6: (a) Doppler of target at element m = +1 (b) Antenna Doppler compensation for
Table 2.2 : Computational Complexities
Table 6.1: Simulation Parameters of 2 targets
Cramre-Rao lower bound (CRB) for DOA, Doppler shift and time delay is given by
Figure 6.2: Phase difference in arrival
Figure 3.13: Target detection with demodulator frequency not including rotation frequency
Figure 4.14 Comparison of Computations
Figure 4.1: Two element array
Figure 5.9: DOAs of 2 targets at 100 Hz Doppler
The stacked pulses are now to be added and processed. After adding the batches from
Figure 6.16: Elevation angles are scanned at azimuth of 6° and 8° for estimation of elevation
MUSIC is higher than the proposed algorithm which requires Eigen value decomposition and
The problem is to find range, Doppler, azimuth and elevation of all the targets present in a
Figure 6.15: Azimuth estimation: 6, = 20°, SVR = 10dB, 0, = 6’,0, =8°
The echoes are received by the antenna elements independently. Information about
length is complete and its result is available. The software ASM flow for the columns FFT
Figure 4.10: ROC curves for different SNRs
Figure 4.5: Stacked pulses
Figure 6.17: Elevation estimation ¢, = 20°, SNR = 10dB, ¢, = 60°, ¢, = 65°
Figure 5.8: Eigen values at (a) 100 Hz Doppler (b) 160 Hz Doppler
Figure 6.6: Cells in a complete Scan The complete scan is divided into K=27/0, cells as shown in Figure 6.6.
5.7.1 Comparison of Computational Complexities
Figure 6.9: Range/Doppler Algorithm shows that the sum of two elements along azimuth is required for azimuth estimation.
The mathematical model of the signal received is present in Eq. (3.9) in chapter 3 which can
Figure 4.11: MSE and CRLB for DOA estimation Vs SNR
Figure 5.10: DOAs of target at 160 Hz Doppler
Figure 6.14: Range of detected Targets
Figure 6.7: Gain of each received Echo
Figure 4.8: Phase plots at (a) element | (b) element 2 Table 4.1: Phase of target at both elements
Figure 6.5: Array Configuration
Figure 4.3: Transformations on received Batch squared, added and peaks are searched by thresholding for the detection of targets.
where T, (x) and T',(x) is the data processed from each element as given
For a given SNR value, the threshold is estimated by using trade-off between the probability Table 5.1: Table of Probabilities of detection and false alarm. Probability of miss is not required because it directly related
It can be seen in Figure 4.7 that after adding all element batches and processing, the
shown in Figure 6.3 We can combine the signals from 2 antennas at same axis. Combining the element output a .2 Azimuth and Elevation Estimation Method
ave processing resources, we can add all batches from all elements and then process the Figure 5.4: Complex demodulator compensates antenna Doppler
Figure 6.18: Comparison of mean square error of different estimators It can be seen in Figure 6.18 that MSE of the proposed estimator is close to the CRLB
Figure 6.4: Combining element output for Elevation estimation Similarly for Elevation estimation, the element output is combined as shown in Figure 6.4 phase diff = Ay = 22dysinO sing / A
The computations of the proposed algorithm are compared with MVDR (Capon’s) algorithm
Figure 4.6: (a) Doppler of target at element m = +1 (b) Antenna Doppler compensation for
Figure 1.6: (a) Doppler and (b) Range Calculation (c) Peak corresponding to target Figure 1.5: Algorithm Flow Diagram
Figure 3.6: Compensation in Processor the integer part of Doppler due to the antenna rotation (see Figure 3.6(b)) resulting data matrix after taking FFT is then shifted along Doppler axis to compensate for already seen in Figure 1.6. But it will also include the antenna rotation Doppler. If the
Figure 7.7: FFT of Rows
summary of algorithm is shown in Figure 1.5 [7]. Figure 1.3: Received echo pulses
2.1 shows main structure of beamformer.
Figure 3.12: Complex demodulator compensates antenna Doppler
Figure 2.3: Resolution Comparison of Beamformers Figure 2.2: Two identical subarrays
Figure 1.2: Multiple signals incident on ULA
The transmitted pulses get the range, Doppler and direction of arrival (DOA) effects
Figure 2.4: RMSE comparison of beamformers resolution due to the output power minimization subject to the constraint.
Figure 1.8: Different cases of pulses received will not be received inside the horizontal beamwidth. the beam in relation with a particular target. If this condition is not met, one complete batch
Figure 3.5: Rotating Antenna Array showing pulses
Figure 3.4: Rotating Antenna Array showing signal for different pulses direction of antenna motion as shown in Figure 3.5 where 9, is the angle for first pulse.
Figure 3.3: Target inside beam of radar radio frequency f is s, ,(t) = Aq(tye!O"® antenna gain (narrow beam). The signal transmitted by antenna m = +1 after up conversion to Consider a target within the beam of transmitting antenna moving with v; velocity in
The FPGA block diagram and coprocessor details are shown in Figure 7.2. The
Figure 3.14: Target detection with demodulator frequency including rotation frequency
Figure 4.7: Targets detected also depends on the Doppler bins i.e. number of pulses stacked. the effectiveness of the proposed modified two dimensional algorithm. This compensation
Figure 4.12: MSE and CRLB for Doppler estimation Vs number of pulses
Figure 4.13: MSE and CRLB for delay estimation Vs number of pulses
Figure 5.2 : Rotating antenna array with target |
Figure 6.11: Scanning azimuth angles along an elevation angle Figure 6.11 shows the beamwidth of 20° along azimuth.
Table 4.2: Table of Computational Complexities
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High-accuracy orientation survey in the Tiberius' Cave near Sperlonga
by Paolo Di Lazzaro and 
2 more
Marina De Franceschini
Giuseppe Veneziano

2022, Journal of Cultural Heritage

We exploit a very accurate electronic solar compass used for the first time in archaeology, to measure the orientation of structures at the Tiberius' Cave, which is adjacent to the Villa of the Roman emperor Tiberius located nearby the... more
Figure 1. Azimuth values of the directions connecting the stations. Stations 5 and 7 are inside the grotto. The values from stations I and 3a (in green) are measured by the ESC and have an accuracy of 1'. The other values (in yellow) are obtained by triangulation and have an accuracy of 2'. The pairs of stations along the walls (1-3a and 3a-6) lie on lines parallel to the respective walls. at eh ee Nee eee Bees The set of measurements in the area of the Tiberius’ Cave allows graphing the various stations and their connections on a Cartesian plane, using the procedure detailed in fig. IV of the Supplementary Material. Each station and each direction are thus geo-referenced. Figure | shows the azimuth of the directions connecting the stations, overlaid on the Google map image.
Figure 2. Simulation of the sunset on the winter solstice of the year 1 AD as seen from niche A, station 7, at 1.7 m. above the sea level. The figure shows the last seven positions of the Sun, at intervals of 0.5°, till the sunset at OH=-3’:47”. The goniometric grid is based on the azimuth values of stations 8 and 6 (see green lines) from station 7. The positions of the Sun are those reported in table 3.
Figure 3. Simulation of the sunset on the summer solstice of the year 1 AD seen from niche B, station 5 (where the group of Polyphemus was located) at 1.7 m above the sea level. The last four positions of the Sun are reported -at intervals of 0.5° angular elevation- before it sets behind the town of Sperlonga, at @H=2.5°. The positions of the Sun are those reported in table 3.
Figure 4. The statue of the ‘Andromeda chained to a rock by the sea' is exhibited at the National Archaeologica Museum of Sperlonga. It was found in the sea nearby the cave [12]. The height of the statue is 1.7 m including the base. According to mythology, Andromeda was offered as a human sacrifice to a sea monster. Fron https://images.app.goo.gl/aHKKEhHx8Hj9IGN97 SE BRE SS AED SV ESEEES GT RE SSO RNPANSIRE TTI” ERNEST, BURL UiRRRR ERTS SSRIS Ratatat Srp anne, ees ere tvsear tno ered hashes Figure 2 shows that the sunset at the winter solstice of the year 1 AD had an azimuth 238°:05' almost coincident (within just 0.2°) with that of the centre of the external niche (station 8) seen from the centre of the cubicle inside the niche A (station 7), which is 237°:53'. The probability of this very accurate alignment being random is small. Whichever 1.7-meter-tall viewfinder or gnomon placed in the circular niche of station 8 could be suitable to project its shadow on the centre of the gate of the cubicle to point out the sunset in the winter solstice. Among the statues found nearby Tiberius’ Cave, only the ‘Andromeda chained to a rock by the sea’ shown in fig. 4 is 1.7-meter tall, and has the arms forming a half-ring suitable to act as a viewfinder. the sea’ shown in fig. 4 is 1.7-meter tall, and has the arms forming a half-ring suitable to act as a viewfinder.
Table 3. The azimuth of the Sun at sunset vs. the angular elevation of the horizon seen from the Tiberius’ Cave. The values are calculated by the app Sunpass at the geographic coordinates of the Tiberius’ Cave (41°:15':1" N, 13°:22':0” E), in the year I AD, using the definition of the sunset as the Sun tangent to the horizon. The correction due to atmospheric refraction is taken into account. Table 3 shows the Sunpass results for the azimuth of the Sun at sunset in the year 1 AD as a function of the angular elevation 9H on the horizon on the dates of the solstices and equinoxes. Here we define “sunset” as the moment when the Sun is tangent to the horizon and the full solar disk is still available to illuminate objects creating perceptible light effects in the cave.
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Navigare tra i pianeti con la bussola 'marziana'
by Paolo Di Lazzaro

2022, Energia Ambiente e Innovazione, n. 3

ENEA ha sviluppato una bussola solare in grado di fornire l'orientamento nei pianeti del sistema solare. Questo strumento può essere adattato ad applicazioni terrestri, in particolare, per la navigazione su mezzi mobili come navi ed... more
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High accuracy azimuth measurements: the ENEA solar compass in its instrumental and smart version
by Paolo Di Lazzaro and 
1 more
Achille Zirizzotti

2021, Il Nuovo Cimento C vol. 44, issue 4-5, 116

The accurate assessment of the azimuth of a given direction as, e. g., the geographic North, is of utmost importance in many fields. The electronic solar compass patented by ENEA achieves an accuracy of 0.01°, it is up to 100 times... more
Fig. 1.— Angle 0;, between the Sun and the solar compass (SC) reference plane II (left). Sketch of the SC, with the slit, the optical sensor (CMOS) and the reference plane II position (right).
TABLE I. — Azimuth of the reference direction (RD) for magnetic declination measurement at Concordia Station, Antarctica, measured with different techniques in past years (see text). The two poles defining RD are about 26 m far and, in the case of GPS measurements, were localised with an error ranging from 10 to 34 mm [11]. The ENEA SC result almost perfectly reproduces the original one obtained with astronomical methods.
Fig. 2. — Sunpass slit method: example of a box to be put below the smartphone camera for Sun direction determination (left); screenshot of the Sunpass Orientation function (right).
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Bussola solare di alta precisione: un utile strumento per l’archeoastronomia
by Paolo Di Lazzaro

2020, Atti del 21mo seminario di archeoastronomia

Presso i Laboratori del Centro Ricerche ENEA di Frascati sono stati realizzati diversi prototipi di bussola solare compatta e in grado di fornire la direzione del Nord geografico in qualunque luogo del pianeta con elevata accuratezza... more
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Accurate and low-cost ENEA solar compass for precision metrology of true azimuth: instrumental and smart versions
by Paolo Di Lazzaro

2020, Proceedings SPIE

The structure and operating principles of a solar compass conceived and realised at the ENEA Laboratories in Frascati are presented. The optical design, the underlying software and the calibration procedure make this instrument a... more
Figure 5. Sequence of azimuth values measured by the SCDT during a 2-days test by pointing a 22-km-far broadcastins antenna from the ENEA Frascati Research Centre. Relieves are separated in time approximately by 1 minute. The horizonta dashed line refers to the average of theoretical azimuth values extracted from different satellite maps according to the procedure detailed in Ref. [9]. The average experimental value is 51.4 + 0.2 arcminutes, and differs less than 0.1’ from the theoretical one. We repeated the survey from another position inside our Research Centre, pointing also other targets. In Tab. | the final results of the tested directions are reported. The worst result shows a deviation from the reference azimuth of only 10° degrees, a value which is comparable with the accuracy of the maps.
Figure 7. Detection of the Sun direction with respect to the smartphone side: a) through the shadow of a pole (this method i: called GNOMON) or of a building edge (SHADOW method); b) by means of the line of light generated by the Sun enterin; in a suitable box put below the smartphone camera (see text). c) Two types of realized boxes, one foldable (on the left), the other stiff; the squares on the background have 25-mm side. As for the SCD, the first point is to detect the Sun rays direction with respect to a reference plane. On one side, the reference plane can simply be the vertical plane parallel to the long side of the smartphone; on the other side, the sunlight cannot directly hit the smartphone camera because it is too intense and would saturate the CCD. The Sun direction can then be detected by framing the shadow of a vertical pole (GNOMON method) or edge (SHADOW method), as depicted in Fig. 7a, or a line of light generated by a dedicated tool, like the simple box sketched in Fig. 7b, having an upper hole and a lateral slit (SLIT method). In this last case, the box is put below and in contact with the smartphone, in such a way that the camera can frame, through the hole, the internal floor of the box where the line of light appears. Some implemented boxes are shown in Fig. 7c. When using SunPass, the operator is requested to choose one of this three methods (plus the simple, direct pointing of the Sun, called FIXED method) before performing the orientation measurement. The smartphone has to be kept horizontal, with the help of the internal inclinometer. Anyway, in the case of the SLIT method, it is possible to ask the software to take into account the smartphone tilt angles in the calculations, thus automatically recovering the non-horizontality.
Figure 4. Photograph of the optical bench used to calibrate the SCDT. A laser beam proceeds vertically through three beam splitters put on a upright rail. Each beam splitter is aligned to reflect a portion of the laser beam toward the SCD, thus simulating sunlight from three different elevation angles, having the same azimuth. To this end we set up a dedicated optical bench where the SCDT is put in front of a set of three beam splitters aligned on a vertical rail, which alternately deflect a low-divergence laser beam toward the slit of the SCD, thus simulating light coming from three different elevations of the Sun with the same azimuth, as shown in Fig. 4. After checking the SCDT horizontality, several measurements are carried out, by rotating in a controlled way the SCDT around the theodolite vertical axis. In this way, the position of the line of light on the CMOS is acquired for different and well knowr illumination conditions (i.e. simulated Sun azimuth and elevation), making the determination of the misalignment parameters possible.
Figure 1. a) Schematic of the electro-optical sensor of the ENEA SCD: the azimuth 0,, of the Sun with respect to a SCD reference plane is obtained by using a vertical slit (see text); b) sketch of the optimal height/inclination choice for detecting the Sun rays throughout the day in every place of the Earth.
inclination and rotation. A set of unavoidable mechanical misalignment parameters has to be defined and inserted in the acquisition/elaboration software; finally, their values must be experimentally attained. Figure 3. The solar compass mounted on a theodolite. The sensitive part of the compass is placed on the top, where a filte: covers the slit, while the box on the legs of the tripod contains the electronics and provides the user interface through < display and buttons.
The main SunPass screen appears like in the central image of Fig. 9, where the cardinal points are drawn in the centre and all the relevant data are indicated. In this case, we were using the Orientation Function with the FIXED method. The method can be chosen by entering the Settings menu, which is shown on the right in Fig. 9. Figure 9. Central image: main page of SunPass, where all the relevant data are displayed and the smartphone orientation is determined. Right image: Settings menu, where the measuring parameters and method are selected. Left image: the Function menu, where, besides the Orientation, other utilities are available (see text).
Figure 6. Results of the azimuth measurements of the reference direction of the geomagnetic observatory in Concordia Station. The data are reported as arcminutes difference with respect to the first astronomical measure. The letters indicate different conditions of the shelters: A=free from snow, B=partially sunk in the ice, C=entirely buried under the ice.
The other available Functions have also a professional use, since they help in installing satellite antennas or solar panels, or in using topographic and cadastral maps, where the North indication as well as the azimuth angular indications are referred to the UTM (Universal Transverse Mercator) meridians rather than to the geographic meridians. Finally, SunPass provides also astronomical information, mainly for educational purposes, with the Ephemerides Function, which can be reached from any page just by pressing the circular icon on the top of the screen. Since the Sun ephemerides are not related to the smartphone performances, their accuracy is the same of the SCDT (0.01°). Figure 10. a) The “Route Direction” Function screen, useful for going towards a given destination: the direction to be followed is indicated with respect to North both by showing its azimuth and by an arrow; b) the “Magnetic declination Measurement” Function screen, where the magnetic North direction is identified by an arrow and the magnetic declination value is shown; the presence of a magnetic compass in the smartphone is necessary.