Showing papers on "Active antenna published in 2010"

Trellis Coded Spatial Modulation

Abstract: Trellis coded modulation (TCM) is a well known scheme that reduces power requirements without any bandwidth expansion. In TCM, only certain sequences of successive constellation points are allowed (mapping by set partitioning). The novel idea in this paper is to apply the TCM concept to the antenna constellation points of spatial modulation (SM). The aim is to enhance SM performance in correlated channel conditions. SM considers the multiple transmit antennas as additional constellation points and maps a first part of a block of information bits to the transmit antenna indices. Therefore, spatial multiplexing gains are retained and spectral efficiency is boosted. The second part of the block of information bits is mapped to a complex symbol using conventional digital modulation schemes. At any particular time instant, only one antenna is active. The receiver estimates the transmitted symbol and the active antenna index and uses the two estimates to retrieve the original block of data bits. In this paper, TCM partitions the entire set of transmit antennas into sub-sets such that the spacing between antennas within a particular sub-set is maximized. The scheme is called trellis coded spatial modulation (TCSM). Tight analytical performance bounds over correlated fading channels are proposed in this paper. In addition, the performance and complexity of TCSM is compared to the performance of SM, coded V-BLAST (vertical Bell Labs layered space-time) applying near optimum sphere decoder algorithm, and Alamouti scheme combined with TCM. Also, the performance of all schemes with turbo coded modulation is presented. It is shown that under the same spectral efficiency, TCSM exhibits significant performance enhancements in the presence of realistic channel conditions such as Rician fading and spatial correlation (SC). In addition, the complexity of the proposed scheme is shown to be 80% less than the V-BLAST complexity.

Broadband, Efficient, Electrically Small Metamaterial-Inspired Antennas Facilitated by Active Near-Field Resonant Parasitic Elements

Abstract: The possibility of using an active internal matching element in several types of metamaterial-inspired, electrically small antennas (ESAs) to overcome their inherent narrow bandwidths is demonstrated. Beginning with the Z antenna, which is frequency tunable through its internal lumped element inductor, a circuit model is developed to determine an internal matching network, i.e., a frequency dependent inductor, which leads to the desired enhanced bandwidth performance. An analytical relation between the resonant frequency and the inductor value is determined via curve fitting of the associated HFSS simulation results. With this inductance-frequency relation defining the inductor values, a broad bandwidth, electrically small Z antenna is established. This internal matching network paradigm is then confirmed by applying it to the electrically small stub and canopy antennas. An electrically small canopy antenna with k? = 0.0467 that has over a 10% bandwidth is finally demonstrated. The potential implementation of the required frequency dependent inductor is also explored with a well-defined active negative impedance converter circuit that reproduces the requisite inductance-frequency relations.

Tunable SIW Cavity Backed Active Antenna Oscillator

Abstract: A substrate integrated waveguide (SIW) cavity backed active slot antenna oscillator is proposed, the operation frequency of which can be tuned by means of a properly connected varactor. The cavity backed structure permits overcoming potential problems such as heat dissipation and unwanted surface wave modes in large array implementations, and may provide better phase noise performance. The use of SIW technology permits a cost-effective fabrication process and simple implementation at millimetre-wave frequency, for radar and communication applications. Full-wave FEM-based analysis is used for the design of the radiating structure, while harmonic balance and transient simulations are employed in the design of the active antenna oscillator and in the study of the stability of its steady-state solutions. Tunable active antenna prototypes have been implemented and measured.

Active Integrated Wearable Textile Antenna With Optimized Noise Characteristics

Abstract: The design of the first wearable active receiving textile antenna in the 2.45 GHz ISM band is addressed for use in personal area networks. The integrated low-noise amplifier is realized on a hybrid textile substrate and positioned directly underneath a wearable patch antenna. The antenna and low-noise amplifier are designed by means of circuit/full-wave co-optimization techniques within a novel multi-platform simulation setup to account for all the losses induced by using textile materials. A good agreement between simulations and measurements is obtained. An available gain of about 12 dB, on top of the passive antenna gain of about 5 dBi, and a noise figure of about 1.3 dB are realized. The effect of the human body on the active antenna performance is investigated by means of on-body measurements.

Coupled structural-electromagnetic-thermal modelling and analysis of active phased array antennas

Abstract: The electromagnetic performance of an active phased array antenna (APAA) is obviously degraded because of structural distortion caused by thermal power consumption and exterior load. The coupled structural-electromagnetic-thermal (SET) model of APAA is developed on the analysis of the phase difference of radiating elements in the aperture field caused by structural displacement including load-displacement and thermal distortion of structure. Based on the cascade coupled finite element analysis of antenna structure, thermal distortion and other structural distortions are obtained. The coupled SET model is verified by analysing the degradation of the electromagnetic performances of a planar hexagonal APAA operating under different temperature distributions and structural constraints.

Analysis of large antenna systems

Abstract: The research presented in this thesis has been conducted within the framework of the Square Kilometre Array (SKA) project. SKA is a next generation radio telescope that will have a receiver sensitivity two orders of magnitude larger than the most sensitive radio telescope currently in operation. To meet the specifications, various low-cost low-noise actively beamformed receiving array antennas are being considered. A major problem in designing these systems is that the present-day commercially available electromagnetic solvers need an excessive amount of memory and simulation time to solve electrically large antenna problems. Moreover, it is essential to be able to analyze the receiver sensitivity of large antenna array systems to understand the sensitivity limiting factors. No dedicated commercial software tools exist that can analyze the receiver sensitivity of entire antenna systems specifically for radio astronomy. The thesis subject deals with two major challenges: (i) To accurately compute the impedance and radiation characteristics of realistically large and complex antenna arrays using only moderate computing power, particularly, of single and dual-polarized arrays of 100+ Tapered Slot Antenna (TSA) elements that are electrically interconnected. If the collection of these elements forms a subarray of a larger system, it is also of interest to analyze an array of disjoint subarrays. (ii) To characterize the system sensitivity of actively beamformed arrays of strongly coupled antenna elements. To address the above challenges, a conventional method-of-moments approach to solving an electric-field integral equation is enhanced using the Characteristic Basis Function Method (CBFM) to handle electrically large antenna problems. The generation of the associated reduced matrix equation is expedited by combining the CBFM with the Adaptive Cross Approximation (ACA) technique. Furthermore, because an overlapping domain decom270 Bibliography position technique is employed, Characteristic Basis Functions (CBFs) are generated that partially overlap to ensure the continuity of the current between adjacent subdomains that are electrically interconnected. While generating the CBFs, edge-singular currents are avoided by a post-windowing technique. Finally, a meshing strategy is proposed to optimally exploit the quasi-Toeplitz symmetry of the reduced moment matrix. The numerical accuracy and efficiency has been determined for numerous cases, among which a dual-polarized interconnected TSA array of 112 elements that has been fabricated and subsequently validated by measurements. The receiver system has been modeled by both a numerical and a semi-analytical method. The models account for a nonuniform brightness temperature distribution of the sky, mismatch effects, noise that emanates from amplifiers inputs and re-enters the system coherently through the mutually coupled antennas (noise coupling), beamformer weights, etc. Results are shown for a practical setup and design rules are derived which demonstrate that minimum receiver noise can be reached by noise matching the low-noise amplifiers to the active antenna reflection coefficient, rather than the passive one. Finally, it is demonstrated that the radiation efficiency of antennas is an important quantity that can degrade the system sensitivity severely. Nevertheless, a number of commercial software tools have shown to be inadequate as the computed efficiency exceeds 100%. A method is proposed which is numerically efficient and robust since it guarantees an efficiency below 100%.

Micro-coaxial micro-fabricated feeds for phased array antennas

Abstract: This paper presents an overview of recent research at the University of Colorado, Boulder, in the area of passive and active antenna arrays. Specifically, micro-coaxial array feed components, fabricated in the Nuvotronics PolyStrata™ process will be discussed as a means to miniaturized phased array. Performance of broadband Wilkinson dividers covering 2–22GHz (11:1 bandwidth) implemented in micro-coaxial lines for active transmit arrays is presented along with assembly methods for standard surface-mount resistors within the micro-coaxial environment. Integration of active devices with micro-coaxial components for 20W transmitters covering the 4–18GHz band is shown, and challenges associated with high power densities and interconnect parasitic are addressed. Ka-band (38 GHz) hybrids resulting in a 4×4 Buttler matrix with patch-like antennas integrated in PolyStrata™are presented. The high-performance micro-coaxial environment is highlighted with its advantages and potential limitations. Frequency-scanned array designs for W and G-band operation are compared for PolyStrata™ micro-coaxial and waveguide-fed arrays. Finally, several other related approaches, including spatially-fed beam-forming arrays, are overviewed.

TerraSAR-X Antenna Calibration and Monitoring Based on a Precise Antenna Model

Abstract: The high flexibility and tight accuracy requirements of modern spaceborne synthetic aperture radar (SAR) systems require innovative technologies to calibrate and process SAR images. To perform accurate pattern correction during SAR processing, an antenna model can be used to derive the multitude of different antenna beams generated by active antenna steering. The application of such an antenna model could be successfully demonstrated for the TerraSAR-X mission, launched in 2007. The methodology and the results of the in-orbit verification with an achieved accuracy of better than ±0.2 dB are reviewed in this paper in detail, showing its outstanding accuracy. Additionally, the results of the antenna pattern long-term monitoring are described, pointing out the high stability of the system.

Portable radio frequency identification (rfid) reader

Abstract: A particular portable radio frequency identification (RFID) reader includes an active antenna array including a plurality of antenna elements to receive RFID signals from RFID devices The antenna elements include control circuitry to control a beam pattern generated by the active antenna array The portable RFID reader further includes sum circuitry and difference circuitry The sum circuitry is operable to determine a sum signal by summing the RFID signals received by at least two of the plurality of antenna elements The difference circuitry is operable to determine a difference signal between the RFID signals received by at least two of the plurality of antenna elements The portable RFID reader also includes a controller to electronically steer the beam pattern and to determine a direction from the RFID reader to a particular RFID device

Active antenna array with modulator-based pre-distortion

Abstract: An active antenna array comprises a plurality of transmission paths, a predistortion modulation signal generator, and a predistortion modulation signal distribution structure. At least two of the plurality of transmission paths comprise a predistortion modulator for modulating a transmission path signal with a predistortion modulation signal generated by the predistortion modulation signal generator and distributed by predistortion modulation signal distribution structure to the at least two of the plurality of transmission paths. A method for predistorting at least two of a plurality of transmission path signals in an active antenna array and computer program products for manufacture and method execution are also claimed.

Active antenna array having analogue transmitter linearisation and a method for predistortion of radio signals

Abstract: An active antenna array for a mobile communications network comprising: a digital signal processor connected to a plurality of digital-to-analogue conversion blocks; a plurality of antenna elements; a plurality of transmission paths, whereby an individual one of the plurality of transmission paths is connected between an individual one of the digital-to-analogue conversion blocks and an individual one of the plurality of antenna elements, whereby an individual one of the plurality of transmission paths comprises a predistorter and a coupler; a plurality of paths connected between an individual one of the couplers and a single combiner; a single feedback path connected between the single combiner and a predistorter coefficient calculation unit; and a coefficient update path connected between the predistorter coefficient calculation unit and at least an individual one of the predistorters. A method for predistortion of radio signals is also disclosed.

Green Radio Technologies [Mobile Radio]

Abstract: Nokia Siemens Networks and Vodafone have successfully tested a new antenna technology designed to reduce carbon emissions and improve the cost efficiency of mobile phone networks for operators. According to the companies, the tests, carried out through the Nokia Siemens Networks Innovation Center (NICE) initiative between the two companies, mark the first time that an integrated active antenna solution has been used on a commercial mobile wideband code division multiple access (WCDMA) telecommunications network. Nokia Siemens Networks Active Antenna incorporates elements of the base station within the antenna, reducing the footprint of base stations and lowering power consumption.

Apparatus for measuring a radiation pattern of an active antenna arrangement

Abstract: An apparatus for measuring a radiation pattern of an active antenna arrangement is provided, where the active antenna arrangement includes one or more radios having dedicated antenna elements in communication with each other. The apparatus has a common module external to the active antenna arrangement and a calibration radio, which is also external to the active antenna arrangement and coupled to the common module. The common module includes a transmit/receive unit and interfacing means for interfacing the common module with the active antenna arrangement, with the calibration radio and with a network node. The common module further includes a measurement device for measuring signals received from the active antenna arrangement.

Communications structures including antennas with filters between antenna elements and ground sheets

Abstract: A communications structure may include a ground sheet, a feed conductor, and an active antenna branch electrically coupled to the feed conductor. A parasitic antenna branch may be electrically coupled to the ground sheet, and the active and parasitic antenna branches may be spaced apart. Moreover, the parasitic antenna branch may be between portions of the active antenna branch and the ground sheet.

Application of the improved matrix type fdtd method for active antenna analysis

Abstract: An improved flnite-difierence time-domain (FDTD) method has been extended to analyze the antennas with complicated lumped/active networks in this paper. The improved FDTD method is based on a novel integral transform and the matrix theory. Combining the novel integral transform with Kirchhofi's circuit laws, the hybrid networks comprised of high order linear and nonlinear elements with arbitrary connection can be modeled by a stable matrix equation. An efiective model is built for linear lumped networks including internal independent sources. A wire antenna loaded with wideband match network and a two-element active patch antenna loaded with Gunn diodes are analyzed by the developed techniques. The analysis results indicate that the improved matrix-type FDTD method is not only sta- ble and accurate, but also time-saving in simulating the complicated hybrid networks.

Asymmetrically thinned active array TR module and antenna architecture

Abstract: An asymmetrically thinned transmit/receive (TR) module and antenna architecture is provided. In one embodiment, the invention relates to an active antenna assembly including at least one multi-channel transmit/receive (TR) module for reducing power consumption, the antenna assembly including the at least one TR module including a first phase shifter, a first switch coupled to the first phase shifter, the first switch configured to switch between a transmit circuit and a receive circuit, the transmit circuit including a plurality of first power amplifiers coupled to the first switch, the receive circuit including a low noise amplifier coupled to the first switch and to a plurality of second switches, where each of the plurality of second switches is configured to switch between one of the plurality of first power amplifiers and the low noise amplifier.

Big dipper multi-mode time service receiving device

Abstract: A Big Dipper multi-mode time service receiving device consists of a broad band time service active antenna and a multi-mode radio frequency receiver module. The technical scheme does not need to arrange a plurality of special frequency range time service antennas according to a navigational satellite and a frequency range; and the radio frequency receiver module does not adopt time division multiplexing technology to switch the local frequency and intermediate frequency filtering frequency points frequently, and does not adopt a tunable mode to switch frequency range and multi-channel demodulation mode, but utilizes software technology to control a programmable intermediate frequency filter to automatically select active standby time service signals by a storage control processor, thus being capable of ensuring the transmission and demodulation quality. In the utility model, as the time service active antenna and the radio frequency receiver module are conducted integrated design, the provided newest circuit design and structure not only improves the flexibility and reliability of the switching of the multi-mode time service, but also is extremely beneficial to reducing the reformation cost of converting the existing CDMA and TD-SCDMA mobile communication base station from the single-mode time service to the multi-mode time service.

Active antenna array having a single dpd lineariser and a method for predistortion of radio signals

Abstract: An active antenna array comprises: a digital signal processor connected to a plurality of digital-to-analogue conversion blocks; a plurality of antenna elements; a plurality of transmission paths, whereby an individual one of the plurality of transmission paths is connected between an individual one of the digital-to-analogue conversion blocks and an individual one of the plurality of antenna elements, whereby an individual one of the plurality of transmission paths comprises a correction signal combiner and a feedback coupler; a plurality of paths connected between individual ones of the feedback couplers and a single feedback combiner; a single feedback path connected between the single feedback combiner and a correction signal calculation unit; and a single correction signal path connected between the correction signal calculation unit and at least two of the correction signal combiners. A method for predistortion of radio signals in the active antenna array is also disclosed.

Active antenna oscillator systems in substrate integrated waveguide (SIW) technology

Abstract: Active antenna oscillator and coupled oscillator topologies are proposed, whose elements are cavity backed antenna oscillators implemented in substrate integrated waveguide (SIW) technology. Compact single substrate implementations are demonstrated. The cavity backed topology allows one to resolve potential heat dissipation problems, and provides a design parameter to control coupling among the oscillator elements. EM simulation and harmonic balance analysis are used to design the radiating structures and trace the various existing periodic steady state solutions. Measurements of small size prototypes are presented. These compact, low cost implementations could be useful in radar and communication applications.

Circuits and Active Antennas for Ultra-Wide Band Pulse Generation and Transmission

Abstract: In this paper, the design and development of a novel active antenna including circuits for Ultra-wide band (UWB) pulse generation and transmission have been described. In this design a pulse with pulse-width approximately 150ps and amplitude 500mV (peak-to- peak) was generated using a single high electron mobility transistor (HEMT) as the active device (and an optional Schottky diode for enhanced performance), this being the simplest circuit for generating UWB pulses as far as we know. This circuit was integrated with a newly designed UWB planar microstrip-fed slot antenna, which is an active antenna in the sense that in addition to radiating the signal, it also acts as a fllter, which tailors the spectrum of the transmitted pulse to a shape close to that recommended for UWB communications. We have also given a quantitative analysis, which explains the operation of the circuit.

Low correlation handset antenna configuration for LTE MIMO applications

Abstract: Multiband operation and especially spatial receive diversity requirement of portable LTE devices pose a huge challenge for a small terminal antenna design: In addition to the coverage of frequencies used in current wireless technologies, operation at new frequency bands is required. Especially deployment of the band at 700 MHz is challenging due to miniaturized size of terminal devices. Effective MIMO system requires multiple antennas receiving uncorrelated signal. In case of small handset devices in which the antennas are unavoidably closely spaced at least in frequencies lower than 1 GHz, the antenna radiation patterns should be dissimilar in order to reach low correlation between the signals received by separate antenna branches. A novel active antenna solution and a compact passive antenna both applicable in small handsets covering LTE bands 12, 13, 14 and 17 (698–798 MHz) as well as band 7 (2500–2690 MHz), GSM850 (824–894 MHz), EGSM900 (880–960 MHz), PCN (1710–1880 MHz), PCS (1850–1990 MHz) and UMTS (1920–2170 MHz) are presented in this paper. Different MIMO configurations are constructed of these antenna designs. It has been shown that it is possible to reach low correlation between two closely spaced, effective handset antennas even at 700 MHz.

Base transceiver station with radiation beam steering and active antenna

Abstract: A base transceiver station for a mobile communications network for communicating with a plurality of subscriber devices within a coverage area comprises an active antenna array with a tilt adaption arrangement to adjust a vertical tilt angle of an antenna beam in dependence of beam tilting control data, and thereby dynamically change the coverage area served by the base transceiver station. The base transceiver station further comprises a beam control device for evaluating the distance of the subscriber devices in the coverage area to the active antenna array and calculating from the distances the beam tilting control data. As the distance of a subscriber device to the antenna is a parameter that may be extracted directly from data that is available anyhow for at least some subscriber devices, this data can be acquired at no extra expense.

Receiving Polarization Agile Active Antenna Based on Injection Locked Harmonic Self Oscillating Mixers

Abstract: A polarization agile active antenna with phase shifter elements based on injection locked third harmonic self oscillating mixers is presented. This phase shifting topology provides the double functionality of continuous range phase shifter and downconverter. The phase shift value introduced by each circuit can be easily tuned through a DC voltage within a theoretical continuous range of 450° . The behavior of the isolated phase shifter circuit is studied, both as a function of the control voltage and versus frequency, through harmonic balance and envelope transient simulations. The polarization tuning performance of the complete active antenna is simulated, analyzing the impact of the operating parameters of the phase shifter on the overall behavior. A receiving polarization agile antenna with an input frequency band centered at 11.25 GHz and an output frequency band centered at 1.5 GHz has been manufactured for the experimental validation of the simulated results. A continuous range of polarization tuning has been observed, including two orthogonal linear polarizations along with left hand and right hand circular polarization.

Impedance characteristics of an active antenna at whistler mode frequencies

Abstract: [1] We use the radio plasma imager (RPI) on the IMAGE satellite to investigate the impedance characteristics of an active electric antenna in space plasma at whistler mode frequencies. A dedicated experiment was carried out on 21–22 September 2005 for two orbits in the plasmasphere. The input impedance characteristics of the dipole antenna submerged in plasma is determined at whistler frequencies. The results are consistent with a physical model in which the antenna is negatively charged to a large voltage and the plasma around each antenna element forms an ion sheath that varies with time in its radius. Within the plasmasphere, these sheaths are a part of the antenna-plasma system and represent a capacitive component of the tuned antenna circuit. It is shown that, inside the plasmasphere, the RPI antenna capacitance varied from 430 to 480 pF. The plasma sheath formed around the antenna in the plasmasphere increases its capacitance by 20%–30% with respect to the near–free space capacitance (364 pF). Comparison of these values to model calculations shows good agreement with a difference smaller than 5%. Measurements of the antenna input resistance showed that, inside the plasmasphere, its value was between 200 and 500 Ω, varying considerably with changes in the ambient electron density and cyclotron frequency. The measured antenna input resistance is compared to model calculations.

Active antenna array and method for calibration of the active antenna array

Abstract: The disclosure relates to an active antenna array for a mobile communication system which comprises a plurality of receive paths, a sounding signal generator generating a sounding signal, and a coupler for coupling the sounding signal into at least one of a plurality of receive paths. A sounding signal extractor substantially removes the sounding signal from digitized ones of the receive signals to form a wanted signal. The disclosure also provides a method for the calibration of the receive path of the active antenna array.

Active antenna array and method for calibration of the active antenna array

Abstract: The disclosure relates to an active antenna array (10) for a mobile communication system which comprises a plurality of receive paths (30-1,..., 30-N), a control unit (105) for generating a sounding signal (110), and a coupler for coupling the sounding signal (110) into at least one of a plurality of receive paths (30-1,..., 30-N), A switch (190) is used to switch the output of one the plurality of receive paths (30-1,..., 30-N) between one of a receiver (Rx) and a calibration unit. The disclosure also provides a method for the calibration of the active antenna array (10) which comprises generating (210) an initial sounding signal (110), coupling the Initial sounding signal (110) into at least one of a plurality of receive paths (30-1,..., 30-N) to generate an adjusted sounding signal (110'), comparing (220) the adjusted sounding signal (110') with an initial sounding signal (110) and than generating (225) calibration parameters.

GPS active antenna on-off detection device

Abstract: The utility model discloses a GPS (Global Positioning System) active antenna on-off detection device which is characterized in that the device comprises a GPS active antenna, a detection circuit, an external detection circuit and a GPS receiver, wherein the detection circuit is connected in series between the GPS active antenna and the GPS receiver, and the output terminal of the detection circuit is connected with the external detection circuit; the detection circuit comprises a capacitor, an inductor, a resistor and two triodes; base electrodes of the triodes are connected with each other, collectors thereof are connected with a 33V power supply voltage via the serial resistor, and emitters thereof are grounded through the serial resistor; and the GPS active antenna is connected with the collector of one triode, of which the emitter is connected with the external detection circuit The device uses simple triodes and a resistor to form the detection circuit achieving the opening of the GPS antenna through detecting the electric current of the GPS antenna, and has the advantages of simple circuit, low cost, small occupied PCB (printed circuit board) space, convenient detection, low influence over the GPS antenna performance, and the like

Active antenna system and method for operation of an active antenna array

Abstract: The application relates to a method for operation of an active antenna array and to an active antenna system. The active antenna system has a signal processing unit and an active antenna array adapted to be operated with a main antenna pattern correlated to a main receive beam and with at least one test antenna pattern correlated to a test receive beam having an orientation different from the main receive beam. A main radio frequency signal is received based on the main antenna pattern and a test radio frequency signal is received based on the test antenna pattern. The main radio frequency signal comprises communications traffic. Performance of the main receive beam is assessed based on the main radio frequency signal and performance of the test receive beam is assessed based on the test radio frequency signal. The main antenna pattern is adjusted based on a comparison of the performance of the main receive beam and test receive beam.

Integrated double-mode time-service active antenna and double-mode analog-digital demodulation module

Abstract: The invention provides an integrated double-mode time-service active antenna and a double-mode analog-digital demodulation module, which comprise a double-mode ceramic medium receiving antenna, a broadband low noise amplifier, a double-mode radio-frequency receiver module, the double-mode analog-digital demodulation module, a double-frequency change-over switch and the like, and is characterized in that: the ceramic medium antenna has double-mode broadband design, and the radio-frequency receiver is decomposed into two parts, namely a mixer unit and an analog-digital demodulation module which are both in a double-mode receiving-demodulating mode Time service signals can be transmitted to a time substrate in a base station in a high-frequency broadband, network data, dual intermediate frequency or single intermediate frequency mode A double-mode time-service frequency range can be the combination of signals of GPS and Beidou second-generation satellite or the combination of time service signals of other different navigation satellites The invention realizes the function of simultaneously receiving and demodulating the clock signals of GPS and the Beidou second-generation satellite through optimized design, and improves the time service reliability and flexibility of the base station