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ADS-B is increasingly used for air traffic control in areas covered by terrestrial receivers; however, its limited range makes it unsuitable for other areas such as oceans. To overcome this limitation, it has been proposed to receive ADS-B signals from low earth orbit nano-satellites and relay them to the terrestrial receivers. This paper gives an...
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... architecture of the decoder is shown in Figure 3. It consists of i) a synchronization block (standard correlation with adaptive threshold based on a moving average and an offset) that detects ADS-B messages (preamble detection), ii) a symbol decoding block (standard correlation with threshold) that decodes the 112-bit data block that follows the pream- ble, and iii) a post-processing block that performs a cyclic redundancy check (CRC) on the data block to verify that a valid message has been decoded properly; valid messages are passed on to the MCU over an SPI link. 1) Synchronizer Implementation: The synchronization block receives 10-bit unsigned data at 16 Mega-samples per second (MSPS) and outputs a synchronization bit and the delayed 10-bit data samples to the symbol decoding block at 16 MSPS. ...
Citations
... Proba-V [34] 2014 GATOSS [35] 2014 CanX-7 [36] 2017 TianTuo-3 [8], [37] 2015 STU-2C [38] 2015 Iridimu-NEXT [39] 2017-2019 TianTuo-5 2020 ...
The Satellite-based Internet of Things (S-IoT) system offers a promising solution for accessing IoT devices in areas where terrestrial networks are inaccessible. These devices have significant roles in various scenarios, including aeronautic and maritime surveillance, data collection from sensors, and distress signals from sinking ships. However, covering numerous IoT targets with a minimal number of satellites poses a challenge. This paper proposes a solution known as the 5S payload designed for S-IoT. The 5S payload integrates five subsystems into a single unit, comprising the following components: (1) Automatic Identification System (AIS) for ship surveillance, (2) Very High-Frequency Data Exchange System (VDES) enabling two-way communication for ships, (3) Automatic Dependent Surveillance-Broadcast (ADS-B) system for aircraft surveillance, (4) Data Collection System (DCS) for user-defined sensors, and (5) Emergency Search and Rescue (ESR) system. The design of the 5S payload adheres to the CubeSat standard and occupies a compact 1.5U size, enabling rapid manufacturing and deployment. The feasibility of the 5S payload was demonstrated on the TianTuo-5 satellite launched on August 23, 2020. Additionally, this paper presents in-orbit experimental results spanning three years to further illustrate the effectiveness of the 5S payload.
... However, the traditional ground-based ADS-B system cannot provide seamless global surveillance due to blind zones at ground stations [3]. In order to solve this problem, researchers have focused on satellite-based ADS-B systems to achieve real-time, continuous, and seamless surveillance globally [4][5][6][7]. ...
... Assuming that the noise following a Gaussian distribution satisfies w~N 0, 10 and the system requires a detection rate of 96%, the T MSED of ADS-B receivers with different sensitivities can be calculated using (18) (as drawn in Figure 4). Figure 4 shows that when the receiver sensitivity is -102 dBm, the result of calculating the T MSED is T MSED = Q −1 P d 2l 1 σ 2 n + σ 2 s 2 + l 1 σ 2 n + σ 2 s ≈ 1891 23 6 International Journal of Aerospace Engineering ...
Existing methods are unable to achieve high detection rates and low false alarm rates of satellite-based Automatic Dependent Surveillance-Broadcast (ADS-B) signal preambles at extremely low signal-to-noise ratios (SNRs) using limited on-star resources. In this paper, a dual-hierarchy synchronization method is proposed, including a first-level coarse synchronization and a second-level fine synchronization. The coarse synchronization process involves three steps: (1) detection of unknown signals, (2) soft decision, and (3) adaptive interval output. The first step introduces the threshold (TMSED) of the minimum signal energy to be detected to guarantee a high detection rate. In the soft decision step, a value (SV) designed to improve the robustness of the system curbs false detection caused by noise interference. In the last step, the coarse synchronization interval radius (r) is mapped out according to the SNR to reduce resource consumption. The fine synchronization process is based on the coarse synchronization output, and the correlation peak is calculated to complete the synchronization of the signal preambles. The results show that the proposed method achieves a high detection rate of 96% at an extremely low SNR using a low sampling frequency of 10 MHz. Furthermore, the adjustment of TMSED allows this method to be applied to ADS-B receivers with different sensitivities. The comprehensive performance of this method to achieve high detection rates and acceptable false alarm rates at extremely low SNRs with limited on-star resources is verified by final simulations to be superior to other methods.
... For these reasons, during the last years, it has been proposed to implement space-based ADS-B receivers using a LEO constellation of small satellites which become part of the complete ATM relay network. In this way it is possible to achieve a low latency and secure global ADS-B coverage [31], [33]. An illustration of a satellite-based ADS-B system is shown in Fig. 4. Some specialized companies offer the services of satellite based ADS-B reception and networking, such as SPIRE [34] and Aireon [35]. ...
Satellite communications (SatComs) have recently entered a period of renewed interest motivated by technological advances and nurtured through private investment and ventures. The present survey aims at capturing the state of the art in SatComs, while highlighting the most promising open research topics. Firstly, the main innovation drivers are motivated, such as new constellation types, on-board processing capabilities, non-terrestrial networks and space-based data collection/processing. Secondly, the most promising applications are described i.e. 5G integration, space communications, Earth observation, aeronautical and maritime tracking and communication. Subsequently, an in-depth literature review is provided across five axes: i) system aspects, ii) air interface, iii) medium access, iv) networking, v) testbeds & prototyping. Finally, a number of future challenges and the respective open research topics are described.
... For these reasons, during the last years, it is proposed to implement space-based ADS-B receivers using a LEO constellation of small satellites which can become part of the complete ATM relay network. In this way is possible to achieve low latency and secure global ADS-B coverage [31], [32]. An illustration of a satellite-based ADS-B system is shown in Fig. 4. Frequent and reliable ADS-B communication from space allows to improve the efficient use of the aerospace and increase the aircraft security. ...
Satellite communications have recently entered a period of renewed interest motivated by technological advances and nurtured through private investment and ventures. The present survey aims at capturing the state of the art in SatComs, while highlighting the most promising open research topics. Firstly, the main innovation drivers are motivated, such as new constellation types, on-board processing capabilities, nonterrestrial networks and space-based data collection/processing. Secondly, the most promising applications are described i.e. 5G integration, space communications, Earth observation, aeronautical and maritime tracking and communication. Subsequently, an in-depth literature review is provided across five axes: i) system aspects, ii) air interface, iii) medium access, iv) networking, v) testbeds & prototyping. Finally, a number of future challenges and the respective open research topics are described.
... Satellite-based ADS-B application is an attractive topic and has been discussed in the literature [13][14][15][16]. Interference and low signal-to-noise ratio (SNR) are two obstacles for receiving the satellite-based ADS-B signals. ...
... Each y[κ i ] (i = 1, 2, 3, 4) is a Gaussian variable, i.e. y[κ i ] ∼ N(A, σ 2 /9). According to (16), it is straightforward that τ is also a Gaussian variable with a mean equal to A and variance equal to σ 2 /36. ...
... Hence, for most of ADS-B signals, both the preamble and DF can be used jointly to estimate the amplitude. The valid indexes can be represented by Ω = {κ 1 , κ 2 , κ 3 , κ 4 , l 1 , l 4 , l 6 , l 8 , l 9 }, as shown in Fig. 2. Equation (16) will be modified to ...
In the satellite‐based application, low signal‐to‐noise ratio (SNR) is a considerable obstacle for automatic dependent surveillance‐broadcast (ADS‐B), leading to some erroneous bit declarations. In this case, the confidence level of each bit should be declared legitimately to make full use of error correction. In this study, the authors focus on methods to optimise the confidence declaration for ADS‐B signals with coherent demodulation scheme. A novel optimal‐threshold labelling method is firstly proposed for known and unknown amplitudes. They also present a dynamic‐threshold labelling method, in which a specific threshold is unnecessary. Detailed theoretical analyses are carried out for the proposed methods and are verified by simulations. Finally, they make a comparison between different confidence level labelling methods in terms of reception performance and complexity. A conclusion is set forth that the methods have a high probability of correct reception at low SNRs.
... The system is not originally designed for space-based receiving, which will raise big challenges for space usage, such as low signal levels, packet overlapping and delays, and large signal Doppler shifts. Several teams have launched satellites with ADS-B receiver, like Proba-V [1] from ESA and GOMX-1 from GOMSpace [2,3]. ...
The Automatic Dependent Surveillance- Broadcast (ADS-B) system is today a standard equipment on civil aircraft, transmitting periodically data packages containing information of key data such as aircraft ID, position, altitude and intention. It is designed for terrestrial based ground station to monitor air traffic flow in certain regions. Space based ADS-B is the idea to place sensitive receivers on board satellites in orbit, which can receive ADS-B packages and relay them the relevant ground stations. The terrestrial ADS-B receiver has been widely applied for airport information system, help monitor and control traffic flow, etc. However, its coverage is strongly limited by sea or mountain conditions. This paper first introduces the CubeSat mission, then discusses the integrated application of ADS-B data received from ground stations and from satellites, analyze their characteristics with statistical results of comparison, and explore the technologies to fuse these two different data resources for an integrated application. The satellite data is based on a Chinese CubeSat, STU-2C, being launched into space on Sept 25th 2015. The ADS-B data received from two different resources have shown a good complementary each other, such as to increase the coverage of space for air traffic, and to monitor the whole space in a better and complete way.
Space-based automatic dependent surveillance-broadcast (ADS-B) receivers can cover thousands of aircraft, each transmitting 6 ⋅ 2 signals per second. As a result, ADS-B signals are very prone to overlap. When the number of aircraft covered by a receiver reaches 3,000, about 90 % of the signals will be overlapping. Overlapped signals can reduce the decoding accuracy of receivers, so that aircraft information cannot be accurately transmitted to the air traffic control (ATC) surveillance system, hence threatening aviation flight safety. It is necessary to propose signal separation algorithms for space-based ADS-B systems. An orthogonal projection linear constrained minimum variance (OPLCMV) algorithm is proposed, which can separate two signals simultaneously based on the linearly constrained minimum variance algorithm by exploiting the characteristics of overlapped signals. Compared with the state-of-the-art extended projection algorithm and the fast independent component analysis algorithm, the OPLCMV method has a higher decoding accuracy for multiple overlapping signals with a small direction difference of arrival or frequency shift. Moreover, the OPLCMV algorithm has a low computational complexity when the number of overlapped signal sources is less than seven.
The oncoming project of the Indonesian National Institute of Aeronautics and Space, LAPAN (Lembaga Penerbangan dan Antariksa Nasional) consists of a Low Earth Orbit multi-mission constellation of telecommunication microsatellites. These satellites will carry a data-collecting platform for early warning systems as the primary payload and several other missions such as air traffic monitoring, ship monitoring, and amateur telecommunication payload. In the primary payload, it will use a multi-purpose transceiver for receiving the early warning sensor then send the data to the ground station. As for the secondary mission, the same concept will also be used. This paper discusses the design and implementation of the multi-purpose transceiver for the secondary payload multi-mission microsatellite. As the basis for baseband and RF front-end design, mission analysis of secondary payload and data rate calculation was conducted. The implementation of the multi-purpose transceiver was based on COTS SDR with GNU radio software architecture. The measurement results of the breadboard model are presented and discussed. The outcome of the test shows that the multi-purpose transceiver with multi-application such as ADS-B receiver, TT&C transceiver, and payload data transmitter has been performed well. The TT&C and payload data transmitter with convolutional code rate r = ½, k = 7 with a maximum data rate of 5 Mbps has been demonstrated. Consequently, it is required to add a 35 dB power amplifier to achieve 27 dBm as per link calculation. Subsequently, the ADS-B receiver requires an additional 30 dB low noise amplifier to achieve G/T -22 dB/K. Finally, to reduce the frequency harmonic generate by the local oscillator, a bandpass filter which has minimum rejection > 30 dB at the cut frequency.
