Low sidelobe characteristics of a dual-frequency base station antenna in the case of electrical beam tilt use

2003 ◽  
Author(s):  
Y. Yamada ◽  
Y. Ebine ◽  
M. Kijima
Keyword(s):  
Base Station ◽  
Dual Frequency ◽  
Low Sidelobe

scholarly journals UAV-LiCAM SYSTEM DEVELOPMENT: CALIBRATION AND GEO-REFERENCING

2018 ◽  
Vol XLII-1 ◽  
pp. 107-114 ◽  
Author(s):  
C. Cortes ◽  
M. Shahbazi ◽  
P. Ménard
Keyword(s):  
Particle Filtering ◽  
System Development ◽  
Low Cost ◽  
Base Station ◽  
Dual Frequency ◽  
Body Frame ◽  
Integrated Sensor ◽  
Sensor Orientation ◽  
Wide Range ◽  
Gnss Measurements

<p><strong>Abstract.</strong> In the last decade, applications of unmanned aerial vehicles (UAVs), as remote-sensing platforms, have extensively been investigated for fine-scale mapping, modeling and monitoring of the environment. In few recent years, integration of 3D laser scanners and cameras onboard UAVs has also received considerable attention as these two sensors provide complementary spatial/spectral information of the environment. Since lidar performs range and bearing measurements in its body-frame, precise GNSS/INS data are required to directly geo-reference the lidar measurements in an object-fixed coordinate system. However, such data comes at the price of tactical-grade inertial navigation sensors enabled with dual-frequency RTK-GNSS receivers, which also necessitates having access to a base station and proper post-processing software. Therefore, such UAV systems equipped with lidar and camera (UAV-LiCam Systems) are too expensive to be accessible to a wide range of users. Hence, new solutions must be developed to eliminate the need for costly navigation sensors. In this paper, a two-fold solution is proposed based on an in-house developed, low-cost system: 1) a multi-sensor self-calibration approach for calibrating the Li-Cam system based on planar and cylindrical multi-directional features; 2) an integrated sensor orientation method for georeferencing based on unscented particle filtering which compensates for time-variant IMU errors and eliminates the need for GNSS measurements.</p>

scholarly journals Feasibility of Using Low-Cost Dual-Frequency GNSS Receivers for Land Surveying

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1956
Author(s):  
Natalia Wielgocka ◽  
Tomasz Hadas ◽  
Adrian Kaczmarek ◽  
Grzegorz Marut
Keyword(s):  
Real Time ◽  
Field Experiments ◽  
Low Cost ◽  
Base Station ◽  
Global Navigation Satellite Systems ◽  
Single Frequency ◽  
Signal Acquisition ◽  
Dual Frequency ◽  
Static Mode ◽  
Land Surveying

Global Navigation Satellite Systems (GNSS) have revolutionized land surveying, by determining position coordinates with centimeter-level accuracy in real-time or up to sub-millimeter accuracy in post-processing solutions. Although low-cost single-frequency receivers do not meet the accuracy requirements of many surveying applications, multi-frequency hardware is expected to overcome the major issues. Therefore, this paper is aimed at investigating the performance of a u-blox ZED-F9P receiver, connected to a u-blox ANN-MB-00-00 antenna, during multiple field experiments. Satisfactory signal acquisition was noticed but it resulted as >7 dB Hz weaker than with a geodetic-grade receiver, especially for low-elevation mask signals. In the static mode, the ambiguity fixing rate reaches 80%, and a horizontal accuracy of few centimeters was achieved during an hour-long session. Similar accuracy was achieved with the Precise Point Positioning (PPP) if a session is extended to at least 2.5 h. Real-Time Kinematic (RTK) and Network RTK measurements achieved a horizontal accuracy better than 5 cm and a sub-decimeter vertical accuracy. If a base station constituted by a low-cost receiver is used, the horizontal accuracy degrades by a factor of two and such a setup may lead to an inaccurate height determination under dynamic surveying conditions, e.g., rotating antenna of the mobile receiver.

scholarly journals PENGGUNAAN KINEMATIK GNSS PRECISE POINT POSITIONING (PPP) PADA SURVEI GAYABERAT AIRBORNE SULAWESI

GEOMATIKA ◽  
2016 ◽  
Vol 22 (2) ◽  
pp. 82
Author(s):  
Prayudha Hartanto
Keyword(s):  
Precise Point Positioning ◽  
Base Station ◽  
Gravity Survey ◽  
Airborne Gravity ◽  
Dual Frequency ◽  
Differential Gps ◽  
Airborne Gravity Survey ◽  
Positioning Method ◽  
Rms Error ◽  
Point Positioning

<p class="judulabstrakindo">                                                              ABSTRAK</p><p class="abstrakindo">Metode <em>Precise Point Positionin</em>g (PPP) adalah metode penentuan posisi teliti yang hanya menggunakan sebuah receiver GNSS dual frekuensi. Metode ini dapat digunakan untuk menentukan posisi teliti objek-objek yang diam (<em>static</em>) maupun bergerak (<em>kinematic</em>). Pada penelitian ini, akan dipaparkan mengenai penggunaan kinematik PPP dalam penentuan posisi pesawat terbang pada survei gayaberat <em>airborne</em> di Sulawesi tahun 2008. Data yang digunakan adalah jalur terbang pesawat pada <em>day of year</em> (DOY) 291 dan 274. Perangkat lunak yang digunakan adalah Waypoint<sup>®</sup> Grafnav. Hasil pengolahan menggunakan metode PPP tersebut kemudian dibandingkan dengan hasil pengolahan data Diferensial GPS (DGPS) dengan 1 titik ikat untuk DOY 291 dan 2 titik ikat untuk DOY 274. Hasil perbandingan pada DOY 291 menunjukkan nilai RMS untuk arah timur, utara dan tinggi masing-masing sebesar 0,024 m; 0,020 m dan 0,039 m. Pada DOY 274, RMS yang diperoleh adalah 0,032 m; 0,011 m dan 0,058 m masing-masing untuk arah timur, utara dan tinggi. Hasil-hasil tersebut mengindikasikan bahwa metode PPP dapat digunakan untuk menentukan posisi pesawat terbang dengan fraksi ketelitian sentimeter. Tingkat ketelitian posisi ini sudah memenuhi syarat untuk digunakan pada survei gayaberat <em>airborne</em>.</p><p class="katakunci"><strong>Kata kunci</strong>: GNSS, kinematik PPP, gayaberat airborne, DGPS</p><p class="katakunci"> </p><p class="abstrak">                                                                ABSTRACT</p><p class="abstraking">The Precise Point Positioning (PPP) is a positioning method which only use a dual frequency GNSS receiver. This method can be used to determine the precise position of either static (static) or moving objects (kinematic). In this paper, we will discuss the application of kinematic PPP for the 2008 Sulawesi airborne gravity survey. By using a commercial GNSS processing software called Waypoint® Grafnav, we determine the PPP solutions for the aircraft trajectory of the day of year (DOY) 291 and 274. Each solution then be compared to the Differential GPS (DGPS) results, which use one base station for DOY 291 and two reference stations for DOY 274. The PPP solution of DOY 291 gives RMS error of 0.024 m eastward, 0.020 m northward, and 0.039 m upward. Moreover, the comparison of DOY 274 gives RMS error of 0.032 m eastward, 0.011 m northward, and 0.058 m upward. These centimeter level RMS errors show that PPP is a compatible positioning method for airborne gravity survey.</p><p class="katakunci"><strong><em>Keywords</em></strong><em>: GNSS, </em><em>k</em><em>inematic PPP, airborne gravity, DGPS</em><em></em></p>

scholarly journals Radiation Pattern Performance of Unequally Linear Arrays with Parasitic Element

2017 ◽  
Vol 6 (1) ◽  
pp. 110
Author(s):  
Noor Ainniesafina Zainal ◽  
Muhammad Ramlee Kamarudin ◽  
Yoshihide Yamada ◽  
Norhudah Seman
Keyword(s):  
Radiation Pattern ◽  
Base Station ◽  
Sidelobe Level ◽  
Linear Arrays ◽  
Parasitic Element ◽  
Array Configuration ◽  
Grating Lobe ◽  
Base Station Antennas ◽  
Low Sidelobe ◽  
Mobile Base

<p>For next generation of 5G mobile base station antennas, multibeam, multifrequency and low sidelobe characteristics requested. Simplify the feeding network will contribute a low feeder loss and frequency dependent. From the previous research by the author, low sidelobe level reported by density tapered array configuration from -13 dB to -16 dB and the result maintained for wideband operation frequency at 28 GHz, 42 GHz, and 56 GHz. However, the grating lobe has occurred due to element spacing larger than a wavelength of higher frequency (56 GHz). In this paper, an investigation was made of the performance of radiation pattern for unequally microstrip linear array antenna in frequency 42 GHz and 56 GHz by loading parasitic elements. The effect of parasitic element to the impedance, gain, and sidelobe level of unequally microstrip linear spaced tapered array also examined. The design has been simulated using Ansoft High Frequency Structural Simulator (HFSS) ver 16.0.</p>

scholarly journals Optimal Design of Aperiodic Reconfigurable Antenna Array Suitable for Broadcasting Applications

Electronics ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 818 ◽  
Author(s):  
Ioannis P. Gravas ◽  
Zaharias D. Zaharis ◽  
Pavlos I. Lazaridis ◽  
Traianos V. Yioultsis ◽  
Nikolaos V. Kantartzis ◽  
...  
Keyword(s):  
Antenna Array ◽  
Optimization Methods ◽  
Base Station ◽  
Service Area ◽  
Center Frequency ◽  
Computational Time ◽  
Full Wave ◽  
Low Sidelobe ◽  
Full Wave Analysis ◽  
Velocity Mutation

An aperiodic reconfigurable microstrip antenna array is designed to serve as a DVB-T base station antenna operating in a single broadcasting channel. The antenna array is optimized at 698 MHz (center frequency of DVB-T channel 49) to concurrently achieve a particular radiation pattern shaping with high forward gain, main lobe tilting and null filling inside the service area, as well as low sidelobe level outside the service area, and low standing wave ratio at the inputs of all the array elements. To concurrently satisfy all the above requirements, both the geometry dimensions and the array feeding weights (amplitudes and phases) are optimized, thus leading to a complex multi-variable and multi-objective problem. The problem is solved by applying a recently developed particle swarm optimization (PSO) improved variant, called PSO with velocity mutation, in conjunction with the CST software package, which is employed by the PSOvm every time a full-wave analysis is required. Furthermore, all the optimization methods found in the CST environment are compared with the PSOvm. The results show that the PSOvm is capable of producing an antenna array geometry, which is closer to the predefined requirements than the geometries derived by the rest of the optimizers, in the least amount of computational time.

scholarly journals An Indoor DFEC Ranging Method for Homologous Base Station Based on GPS L1 and BeiDou B1 Signals

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2225
Author(s):  
Heng Zhang ◽  
Shuguo Pan ◽  
Chuanzhen Sheng ◽  
Xingli Gan ◽  
Baoguo Yu ◽  
...  
Keyword(s):  
Phase Relationship ◽  
Typical Feature ◽  
Base Station ◽  
Observation Data ◽  
Dual Frequency ◽  
Positioning Accuracy ◽  
True Value ◽  
Wireless Environment ◽  
Spatial Noise ◽  
Characteristic Points

High-precision navigation and positioning technology for indoor areas has become one of the research hotspots in the current navigation field. However, due to the complexity of the indoor environment, this technology direction is also one of the research difficulties. At present, our common indoor positioning methods are WIFI, Bluetooth, LED, ultrasound and pseudo satellite. However, due to the problem of inaccurate direct or indirect ranging, the positioning accuracy is usually affected, which makes the final application difficult to achieve. In order to avoid the ranging limitations of the existing methods, a new dual-frequency entanglement constraint (DFEC) ranging method based on homologous base station is proposed in this paper. The relationship between the homologous characteristics of dual-frequency signals and the phase relationship within the cycle is used to estimate the current carrier phase adjustment the true value of the cycle count is used to get rid of the constraints of the ranging conditions and improve the ranging accuracy. In order to verify the feasibility of this method, the wired environment test and the typical characteristic points of wireless environment are tested and analyzed respectively. The analysis results show that in the wired environment, the transmitting base station and the receiving terminal will introduce a ranging error of one wavelength; in the wireless environment, due to the influence of spatial noise and multipath, the error of the estimation of the whole cycles of the ranging value increases significantly. And this phenomenon is most obvious especially in the region where the signal is shaded, but the error estimate that satisfies ± 1 wavelength still accounts for 90%. Based on this, we conduct multiple observation data collection at five typical feature points, and used existing MATLAB positioning algorithms to conduct positioning error tests. The analysis found that under this error condition, the positioning accuracy was about 0.6 m, and 93% of the points met the 1-m positioning accuracy.

scholarly journals Assessment of Static Positioning Accuracy Using Low-Cost Smartphone GPS Devices for Geodetic Survey Points’ Determination and Monitoring

2020 ◽  
Vol 10 (15) ◽  
pp. 5308 ◽  
Author(s):  
Marcin Uradziński ◽  
Mieczysław Bakuła
Keyword(s):  
Mobile Phones ◽  
Carrier Phase ◽  
Low Cost ◽  
Satellite System ◽  
Base Station ◽  
Dual Frequency ◽  
Post Processing ◽  
Positioning Accuracy ◽  
Static Mode ◽  
Ambiguity Fixing

Recent developments enable to access raw Global Navigation Satellite System (GNSS) measurements of mobile phones. Initially, researchers using signals gathered by mobile phones for high accuracy surveying were not successful in ambiguity fixing. Nowadays, GNSS chips, which are built in the latest smartphones, deliver code and primarily carrier phase observations available for detailed analysis in post-processing applications. Therefore, we decided to check the performance of carrier phase ambiguity fixing and positioning accuracy results of the latest Huawei P30 pro smartphone equipped with a dual-frequency GNSS receiver. We collected 3 h of raw static data in separate sessions at a known point location. For two sessions, the mobile phone was mounted vertically and for the third one—horizontally. At the same time, a high-class geodetic receiver was used for L1 and L5 signal comparison purposes. The carrier phase measurements were processed using commercial post-processing software with reference to the closest base station observations located 4 km away. Additionally, 1 h sessions were divided into 10, 15, 20 and 30 min separate sub-sessions to check the accuracy of the surveying results in fast static mode. According to the post-processing results, we were able to fix all L1 ambiguities based on Global Positioning System (GPS)-only satellite constellation. In comparison to the fixed reference point position, all three 1 h static session results were at centimeters level of accuracy (1–4 cm). For fast static surveying mode, the best results were obtained for 20 and 30 min sessions, where average accuracy was also at centimeters level.

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