CN107483153B - Satellite-borne multi-channel ADS-B signal processing method - Google Patents
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Abstract
The invention provides a satellite-borne multi-channel ADS-B signal processing method, which comprises the following steps: s1: performing header detection on the ADS-B signal subjected to AD sampling according to a preset multiplying power to acquire header information and reference power; s2: according to the reference power, bit demodulation and confidence degree calibration are carried out on the ADS-B signal by adopting a baseline multi-point technology; s3: and performing strong CRC error correction on the demodulated bit according to the marked confidence degree, and finally outputting the ADS-B1090 ES message of the target bit. The method can effectively meet the special requirements of ground ADS-B standard system application and satellite-borne multi-channel application; the method has strong real-time data processing capacity, and meets the application requirements of wide receiving coverage range and numerous airplanes in the area; the method has low requirement on the power adaptability of the received signals, good sensitivity and overlapping signal separation capability and low transmission error rate.
Description
Technical Field
The invention relates to the technical field of spacecraft signal software processing, in particular to a satellite-borne multi-channel ADS-B signal processing method.
Background
The ADS-B (Automatic Dependent Surveillance-Broadcast) technology is a very important communication and Surveillance technology in a new navigation system, is a brand new technology, organically combines conflict detection, conflict avoidance, conflict resolution, ATC Surveillance, ATC consistency Surveillance and cabin comprehensive information display, enhances and expands very rich functions for the new navigation system, and redefines three major elements in current air traffic control, such as communication, navigation and Surveillance.
Automatic-Automatic, "all-weather operation", does not need to be attended. Dependent-correlation, which only needs to rely on accurate global satellite navigation positioning data. Surveillance-monitoring, monitoring (obtaining) aircraft position, altitude, speed, heading, identification number, and other information. Broadcast-Broadcast, without reply, the airplanes Broadcast their respective data information to each other with the ground station.
The airplane broadcasts the identity, longitude and latitude position, altitude, speed and other information to the surrounding airplanes and ground stations, and simultaneously receives the similar signals broadcast by other surrounding airplanes. All airplanes assembled with the ADS-B system randomly and automatically broadcast ADS-B signals, the ADS-B loads are novel satellite loads, a large number of signal sources are provided for receiving and processing the ADS-B signals of the airplanes by the satellites, and the signals are used for the air traffic control system. According to the project, a satellite-borne ADS-B signal receiving and processing technology is researched, the high-altitude advantages of a satellite platform are utilized to realize large-range, near-real-time and continuous tracking and monitoring of the flight state of the airplane, and particularly all-weather monitoring is carried out on the weak areas covered by a ground air system, such as the ocean, the arctic, the desert and remote areas with high ground system investment cost, and the like, so that the flight safety, the flight efficiency and the air space utilization rate of the airplane are greatly improved.
However, the ADS-B signal processing method in the prior art cannot meet the special requirements of the application of the ground ADS-B standard system and the application of the satellite-borne multi-channel, has poor real-time data processing capability, and has high requirement on the power adaptability of the received signal.
Disclosure of Invention
The invention aims to provide a satellite-borne multi-channel ADS-B signal processing method to solve the problems that the application of a ground ADS-B standard system and the special requirements of satellite-borne multi-channel application cannot be considered, the real-time data processing capability is poor, and the requirement on the power adaptability of received signals is high in the existing ADS-B signal processing method.
In order to achieve the purpose, the invention provides a satellite-borne multi-channel ADS-B signal processing method, which comprises the following steps:
s1: performing header detection on the ADS-B signal subjected to AD sampling according to a preset multiplying power to acquire header information and reference power;
s2: according to the reference power, bit demodulation and confidence degree calibration are carried out on the ADS-B signal by adopting a baseline multi-point technology;
s3: and carrying out strong CRC error correction on the demodulated bit according to the marked confidence degree, and finally outputting the ADS-B1090 ES message of the target bit.
Preferably, the step S1 further includes:
s11: sampling the received ADS-B signal with the preset multiplying power of 10 times to obtain AD sampling data, and performing frame header synchronization processing of 8 bytes;
s12: according to the ADS-B protocol requirement, determining the pulse of the initial position of 0us for four pulses of the message header on 0us, 1.0us, 3.5us and 4.5us, detecting the pulses of 1.0us, 3.5us and 4.5us positions and allowing the position offset of two bits before and after any position of 1.0us, 3.5us and 4.5us to be the same, so as to obtain header information;
s13: selecting the peak amplitudes of 4 leading pulses of the ADS-B information header to calculate the reference power, eliminating sampling points with amplitude variation exceeding a preset threshold value, and sampling the residual sampling points after elimination according to the principle of minimum variance to calculate the reference power of the amplitude to obtain the reference power.
Preferably, the step S2 further includes:
s21: classifying the AD sampled data into class I sampling points and class II sampling points according to the reference power, and establishing an amplitude discrimination window for classifying the class I sampling points and the class II sampling points;
s22: performing bit demodulation, specifically: firstly, judging the number of class I sampling points and class II sampling points in all sampling points in AD sampling data through the amplitude discrimination window, wherein the weight of the number of the sampling points in a preset range close to a pulse transition section in all the sampling points is a first weight, and the weight of the number of the sampling points in the preset range close to a peak value of a pulse is a second weight; calculating the difference between the number of the class I sampling points and the number of the class II sampling points in the weighted whole sampling points, if the difference value is greater than 0, demodulating the corresponding bits of the whole sampling points to be 1, otherwise, demodulating the bits to be 0;
s23: if the absolute value of the difference is larger than 5, the confidence coefficient is calibrated to be high confidence coefficient, otherwise, the confidence coefficient is calibrated to be low confidence coefficient.
Preferably, in the step S11, the amplitude discrimination window defines that the sampling points within a range of ± 3dB from the reference power in the AD sampled data are class i sampling points, and the sampling points within a range of 6dB from the AD sampled data that are smaller than the reference power are class ii sampling points.
Preferably, the step S2 further includes:
s24: compensating the demodulated bit according to the calibrated confidence coefficient, specifically: if any bit is calibrated to be low confidence, judging whether the amplitude sum of the front half sampling points in all the sampling points is larger than the amplitude sum of the rear half sampling points, and if so, modifying the bit to be 1; and simultaneously judging whether the amplitude sum of the front half of all the sampling points is greater than the preset multiple of the amplitude sum of the rear half of all the sampling points, and if so, modifying the confidence coefficient of the bit to be high.
Preferably, the step S3 further includes:
s31: according to the calibrated confidence coefficient, determining the application range of CRC error correction as a bit with low confidence coefficient;
s32: calculating a bit syndrome, wherein when the current bit is 1 and the other bits are 0, the bit syndrome is a remainder obtained after the bits of the demodulated data pass through a CRC (cyclic redundancy check) circuit; if the bit syndrome corresponding to a plurality of bits is selected, and the plurality of bits are subjected to exclusive-or addition to obtain a combined syndrome, the combined syndrome is equal to the bit syndrome generated by a CRC decoding circuit after the plurality of bits are combined, wherein the plurality of bits are set to be 1 after the plurality of bits are combined, and other bits are all 0;
s33: obtaining a final message with a target bit number of 112 bits by a powerful error correction method for a bit syndrome and a 24-bit error pattern corresponding to each bit of known 88-bit data, wherein the powerful error correction method comprises the following steps:
s331: judging whether the data block has no bit with low confidence coefficient or whether the number of the bit with low confidence coefficient exceeds 5, if so, discarding the current response data;
s332: judging whether the number of the bits with low confidence coefficient is more than or equal to 1 and less than or equal to 5, if so, entering the next step for error correction;
s333: randomly combining the bit syndromes of the bits with low confidence, and if a certain combination is equal to the error pattern, negating the bit corresponding to the bit syndrome forming the combination, setting the bit syndrome as high confidence, and completing error correction; otherwise, the message frame is discarded.
Preferably, the powerful error correction method further includes: when there are two or more combinations of bit syndromes that match the error pattern, the one with the smaller combination of bit syndromes is selected.
The method of the invention has the following beneficial effects:
(1) the method can effectively meet the special requirements of ground ADS-B standard system application and satellite-borne multi-channel application;
(2) the method has strong real-time data processing capacity, and meets the application requirements of wide receiving coverage range and numerous airplanes in the area;
(3) the method has low requirement on the power adaptability of the received signals, better sensitivity and better separation capability of overlapped signals, and low transmission error rate.
Drawings
FIG. 1 is an overall flow chart of the method of the present invention;
FIG. 2 is a schematic diagram of a satellite-borne system to which the method of the present invention is applied;
FIG. 3 is a schematic diagram of a signal transmitter-receiver system in accordance with a preferred embodiment of the present invention;
fig. 4 is a data flow diagram illustrating the ADS-B signal processing according to the preferred embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described and discussed in detail below with reference to the accompanying drawings, and it is obvious that the embodiments of the present invention are described herein only in a part of examples, and not in all examples, and all other embodiments obtained by those skilled in the art without any inventive work based on the embodiments of the present invention belong to the scope of the present invention.
For the convenience of understanding the embodiments of the present invention, the following description will be further explained by taking specific embodiments as examples with reference to the drawings, and the embodiments are not to be construed as limiting the embodiments of the present invention.
As shown in fig. 1, the method for processing a satellite-borne multi-channel ADS-B signal provided by this embodiment includes the following steps:
s1: performing header detection on the ADS-B signal subjected to AD sampling according to a preset multiplying power to acquire header information and reference power;
s2: according to the reference power, bit demodulation and confidence degree calibration are carried out on the ADS-B signal by adopting a baseline multi-point technology;
s3: and carrying out strong CRC error correction on the demodulated bit according to the marked confidence degree, and finally outputting the ADS-B1090 ES message of the target bit.
In particular, the spacecraft receiver system to which the method is applicable needs to have the following two conditions:
1. received signal power requirement
Because the method optimizes the software demodulation and error correction algorithm based on the combination of the ground ADS-B standard algorithm and the satellite-borne application, the power of the receiver system is not required to be increased, and the requirements on the sensitivity of the receiver and the power of the received signal are not special and basically consistent with those of a ground receiver.
2. Processing capability for overlapping signals
The area of the coverage area of the satellite-borne multi-channel ADS-B signal machine is large, the number of airplanes in the coverage area is large, and the signal overlapping condition caused by the large number of messages is very serious. The core function of the method of the embodiment is to improve the sensitivity of the receiver to meet the requirement of the satellite-borne environment on the premise of not making great changes on the structure of the receiver. The method also has certain overlap resolution capability, and has certain resolving capability for large signals under the condition of large power difference of overlapped signals under the condition of double overlapping.
In view of the above two conditions that are satisfied by a general spacecraft receiver system, the method of the embodiment can be applied to most spacecraft receiver systems to perform the receiving processing of the ADS-B signal.
As shown in FIG. 2, the satellite-borne system used by the method consists of a satellite receiver 1, a ground receiving station 2 and an airborne ADS-B transceiver device 3. The satellite in which the satellite receiver 1 is located runs in an orbit 700km away from the ground, and the flying speed v is 7400m/s, which has the main advantage of wide coverage range, and the maximum coverage range can reach 3200 km. The receiving system antenna section has 7 beams in total divided into 1 central beam and 6 surrounding beams in terms of azimuth.
As shown in fig. 3, the data source includes information such as position, velocity, time, and the like provided by a satellite navigation system of an aircraft, information such as atmospheric altitude, and call information, the data source is modulated by a signal generating unit of a transmitter system of an onboard ADS-B transceiver device, then transmitted to a transmitting antenna through a signal transmitting unit for transmission, and then received by a receiver system of the onboard ADS-B transceiver device through the receiving antenna, and then transmitted to a satellite-borne seven-channel ADS _ B signal processing unit by a signal receiving unit for processing, and then transmitted to a ground client application such as aircraft track display, air traffic control collision avoidance, or other applications through a relay link.
The satellite can continuously receive ADS-B messages sent by airborne equipment of airplanes in a covered area, the format of the 112-bit ADS-B messages in the embodiment is shown in table 1, only bit demodulation is completed on the satellite and the messages are continuously sent to the ground receiving station through the data transmission module, and the ground receiving station can selectively solve the content according to the needs of the ground receiving station.
ADS-B1090 message format of table 1 standard
In an on-board environment, due to the crowded spatial environment and severe signal overlap conditions, it is not emphasized that a correct solution is achieved for each frame of signal. A significant indicator is target detection success rate (PTA), which refers to the probability of successfully receiving a parity location message within a required time. In a satellite-borne environment, the most concerned is the position information of an aircraft, and when a satellite successfully receives a parity position message of a certain target within a certain time, the latitude and longitude can be extracted by utilizing a global CPR resolving algorithm so as to determine the position information of the target.
The embodiment specifically adopts a satellite-borne multi-channel ADS-B signal processing method, and the ADS-B signals received from seven paths of PPM codes are subjected to signal demodulation and error correction processing, and finally 112-bit ADS-B1090 ES messages are output.
The receiver system has stronger real-time data processing capacity by using the method, and meets the application requirements of wide receiving coverage range and numerous airplanes in the area; the method has the advantages of low requirement on power adaptability of received signals, good sensitivity, good capability of separating overlapped signals, low transmission error rate, and good universality and expansibility.
The following detailed description of the above method with reference to the data stream of the ADS-B signal processing by the spacecraft receiver software of fig. 4 is as follows:
the step S1 specifically includes:
step S11: AD sampling and frame header synchronization processing;
specifically, AD sampling with preset multiplying power ten times is performed on the received 1090MHZ ADS-B signal, AD sampling data with 1260-word length is obtained, and frame header synchronization processing of 8-word frame header characteristic values is performed.
Step S12: detecting a header;
specifically, header detection is completed, four pulses exist on 0us, 1.0us, 3.5us and 4.5us of a message header according to the requirements of the ADS-B protocol, the pulses at the positions of 1.0us, 3.5us and 4.5us are detected under the condition that a starting position (0us position) is determined in consideration of signal interference, and the position deviation (+ -0.2 us) of two bits before and after any position of 1.0us, 3.5us and 4.5us is allowed to obtain header information.
Step S13, calculating an amplitude reference value;
the step mainly selects the peak amplitudes of 4 leading pulses of the ADS-B information header to calculate the reference power value, eliminates the sampling points with amplitude variation exceeding a preset threshold value, and samples the residual sampling points after elimination according to the principle of minimum variance to calculate the reference power of the amplitude to obtain the reference power. In the step, sampling points with small floating are sampled according to the principle of minimum variance to calculate the amplitude reference value, the sampling points with large amplitude variation are removed, and the sampling points do not participate in the calculation of the amplitude reference value, so that the calculation result is more accurate.
The step S2 further includes:
step S21: establishing an amplitude discrimination window;
specifically, the AD sampled data is classified into class I sampling points and class II sampling points according to the reference power, and amplitude discrimination windows for classifying the class I sampling points and the class II sampling points are established. The step is mainly to classify the AD sampling data according to the amplitude reference value, wherein the amplitude discrimination window defines that the AD sampling data which belongs to the range of +/-3 dB of the amplitude reference value is regarded as a class I sampling point (normal sampling point), and the AD sampling data which is smaller than 6dB of the amplitude reference value is regarded as a class II sampling point (abnormal sampling point).
Step S22: carrying out bit demodulation;
the method specifically comprises the following steps: firstly, judging the number of class I sampling points and class II sampling points in all the sampling points in the AD sampled data through the amplitude discrimination window, wherein the weight of the number of the sampling points in a preset range close to a pulse transition section in all the sampling points is a first weight, and the weight of the number of the sampling points in the preset range close to the peak value of a pulse is a second weight; and calculating the difference between the number of the I-type sampling points and the number of the II-type sampling points in all the weighted sampling points, if the difference value is greater than 0, demodulating the bits corresponding to all the sampling points to be 1, otherwise, demodulating the bits to be 0. In this embodiment, this step mainly calculates the difference between the numbers of 10 sampling points falling into two decision ranges (I, II types), where the number of sampling points near the transition of the pulse among the 10 sampling points is weighted to be 1 (first weight), and the number of sampling points near the peak of the pulse is weighted to be 3 (second weight). If the difference is greater than 0, the bit corresponding to the 10 sampling points is 1, otherwise, the bit is 0.
Step S23: calibrating confidence coefficient;
this step is mainly to determine the difference calculated in step S22, and if the absolute value of the difference is greater than 5, the confidence is calibrated to be high confidence (1), otherwise, the confidence is calibrated to be low confidence (0).
Step S2 further includes:
step S24: compensating the demodulated bit according to the calibrated confidence coefficient, specifically: if any bit is calibrated to be low confidence, judging whether the amplitude sum of the front half sampling points in all the sampling points is larger than the amplitude sum of the rear half sampling points, and if so, modifying the bit to be 1; and simultaneously judging whether the amplitude sum of the front half sampling points in all the sampling points is greater than the preset multiple of the amplitude sum of the rear half sampling points, and if so, modifying the confidence coefficient of the bit to be high. Step b 4: and (4) a confidence coefficient compensation algorithm. This step mainly compensates the result of step S23, and if a certain bit is determined as low confidence (0), the simplest amplitude determination method can be used to determine again once, that is, the amplitude sum of the first 5 sampling points is greater than the amplitude sum of the last 5 sampling points, the bit is modified to 1, and meanwhile, if the ratio between the amplitude sums of the first 5 sampling points and the last 5 sampling points is greater than 1.1875 times (the preset multiple specifically set in this embodiment), the confidence of the bit is modified to be high (1).
Step S3 further includes:
step S31: determining an error correction application range;
and determining the applicable range of CRC error correction as bits with low confidence coefficient according to the calibrated confidence coefficient. The step is used for determining an object suitable for an error correction algorithm, and all possible errors in a data block of the ADS-B signal are limited in bits with low confidence coefficient by using judgment of high and low confidence coefficients, so that the error correction range is determined.
Step S32: calculating a syndrome;
specifically, when the current bit is 1 and the other bits are 0, the bit syndrome is the remainder obtained after the bits of the demodulated data pass through the CRC check circuit; if the bit syndrome corresponding to a plurality of bits is selected, and the plurality of bits are subjected to exclusive-or addition to obtain a combined syndrome, the combined syndrome is equal to the bit syndrome generated by the combined result of the plurality of bits through the CRC decoding circuit, wherein the combined result of the plurality of bits is that the plurality of bits are set to be 1, and other bits are all 0.
Step c 3: performing powerful error correction;
and obtaining a final message with the target digit of 112 bits by a powerful error correction method according to the known bit syndrome and 24-bit error pattern corresponding to each bit of 88-bit data. This step is performed in 112 bits, with the bit syndrome and 24-bit error pattern corresponding to each bit of all 88-bit data known, as follows:
firstly, judging whether no bit with low confidence coefficient exists in a data block or whether the number of the bit with low confidence coefficient exceeds 5, if so, not performing error correction, and discarding the current response data;
secondly, judging whether the number of the bits with low confidence coefficient is more than or equal to 1 and less than or equal to 5, if so, possibly carrying out error correction, and entering the next step for carrying out error correction;
then, randomly combining the bit syndromes with low confidence (exclusive or according to bits), and if a certain combination is equal to the error pattern, negating the bit corresponding to the bit syndrome forming the combination, setting the bit syndrome as high confidence, and finishing error correction; otherwise, the error can not be corrected, if a bit with high confidence level is in error, the current message frame is discarded.
The brute force error correction method further comprises the following steps: there is a special case where two or more bit syndrome combinations match the error pattern. Since the smaller the number of bit errors, the greater the probability of occurrence, the one with the fewer combinations of bit syndromes should be selected at this time.
When the method is implemented, a certain model is taken as an example, a single CPU of the model is TMS320C6455, source program codes are written by using C language, signal demodulation and error correction processing are carried out on the ADS-B signals received by the seven paths of PPM codes, and finally 112-bit ADS-B1090 ES messages are output.
As can be seen from the above, the processing method adopted by the receiver system obtains the header information and the power reference value based on the principle of maximum likelihood correlation decision; bit demodulation and confidence degree calibration are carried out by adopting a baseline multi-sampling point technology; strong CRC error correction is carried out on the demodulated bits according to the confidence degree, so that the method has strong real-time data processing capability and meets the application requirements of wide receiving coverage range and numerous airplanes in the region; the method has the advantages of low requirement on power adaptability of received signals, good sensitivity, good capability of separating overlapped signals, low transmission error rate, and good universality and expansibility.
The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be able to make modifications or substitutions within the technical scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (6)
1. A satellite-borne multi-channel ADS-B signal processing method is characterized by comprising the following steps:
s1: performing header detection on the ADS-B signal subjected to AD sampling according to a preset multiplying power to acquire header information and reference power;
s2: according to the reference power, bit demodulation and confidence degree calibration are carried out on the ADS-B signal by adopting a baseline multi-point technology; wherein the calibrated confidence is a high confidence or a low confidence, and the compensating for the demodulated bit according to the calibrated confidence is specifically: if any bit is calibrated to be low confidence, judging whether the amplitude sum of the front half sampling points in all the sampling points is larger than the amplitude sum of the rear half sampling points, and if so, modifying the bit to be 1; simultaneously judging whether the amplitude sum of the front half sampling points in all the sampling points is greater than the preset multiple of the amplitude sum of the rear half sampling points, if so, modifying the confidence coefficient of the bit to be high;
s3: and performing strong CRC error correction on the demodulated bit according to the marked confidence degree, and finally outputting the ADS-B1090 ES message of the target bit.
2. The on-board multi-channel ADS-B signal processing method of claim 1, wherein the step S1 further comprises:
s11: sampling the received ADS-B signal with the preset multiplying power of 10 times to obtain AD sampling data, and performing frame header synchronization processing of 8 bytes;
s12: according to the ADS-B protocol requirement, for four pulses of a message header on 0us, 1.0us, 3.5us and 4.5us, firstly determining a pulse at the starting position of 0us, then detecting the pulses at the positions of 1.0us, 3.5us and 4.5us and allowing the position offset of two bits before and after any position of 1.0us, 3.5us and 4.5us to be +/-0.2 us to obtain header information;
s13: selecting the peak amplitudes of 4 leading pulses of the ADS-B information header to calculate the reference power, eliminating sampling points with amplitude variation exceeding a preset threshold value, and sampling the residual sampling points after elimination according to the principle of minimum variance to calculate the reference power of the amplitude to obtain the reference power.
3. The on-board multi-channel ADS-B signal processing method according to claim 1 or 2, wherein the step S2 further includes:
s21: classifying the AD sampled data into class I sampling points and class II sampling points according to the reference power, and establishing an amplitude discrimination window for classifying the class I sampling points and the class II sampling points;
s22: performing bit demodulation, specifically: firstly, judging the number of class I sampling points and class II sampling points in all the sampling points in the AD sampled data through the amplitude discrimination window, wherein the weight of the number of the sampling points in a preset range close to a pulse transition section in all the sampling points is a first weight, and the weight of the number of the sampling points in the preset range close to the peak value of a pulse is a second weight; calculating the difference between the number of the class I sampling points and the number of the class II sampling points in all the weighted sampling points, if the difference value is greater than 0, demodulating the bit positions corresponding to all the sampling points to be 1, otherwise, demodulating the bit positions to be 0;
s23: if the absolute value of the difference is larger than 5, the confidence coefficient is calibrated to be high confidence coefficient, otherwise, the confidence coefficient is calibrated to be low confidence coefficient.
4. The on-board multi-channel ADS-B signal processing method of claim 3, wherein in step S11, an amplitude discrimination window defines class I sampling points within a range of ± 3dB of the reference power in the AD sampled data, and class II sampling points within a range of 6dB less than the reference power in the AD sampled data.
5. The on-board multi-channel ADS-B signal processing method of claim 1, wherein the step S3 further comprises:
s31: according to the calibrated confidence coefficient, determining the application range of CRC error correction as a bit with low confidence coefficient;
s32: calculating a bit syndrome, wherein when the current bit is 1 and the other bits are 0, the bit syndrome is a remainder obtained after the bits of the demodulated data pass through a CRC (cyclic redundancy check) circuit; if the bit syndrome corresponding to a plurality of bits is selected, and the plurality of bits are subjected to exclusive-or addition to obtain a combined syndrome, the combined syndrome is equal to the bit syndrome generated by a CRC decoding circuit after the plurality of bits are combined, wherein the plurality of bits are set to be 1 after the plurality of bits are combined, and other bits are all 0;
s33: obtaining a final message with a target bit number of 112 bits by a powerful error correction method for a bit syndrome and a 24-bit error pattern corresponding to each bit of known 88-bit data, wherein the powerful error correction method comprises the following steps:
s331: judging whether no bit with low confidence coefficient exists in the data block or whether the number of the bit with low confidence coefficient exceeds 5, if so, discarding the current response data;
s332: judging whether the number of the bits with low confidence coefficient is more than or equal to 1 and less than or equal to 5, if so, entering the next step for error correction;
s333: randomly combining the bit syndromes of the bits with low confidence, and if a certain combination is equal to the error pattern, negating the bit corresponding to the bit syndrome forming the combination, setting the bit syndrome as high confidence, and completing error correction; otherwise, the message frame is discarded.
6. The on-board multi-channel ADS-B signal processing method of claim 5,
the brute force error correction method further comprises the following steps: when there are two or more combinations of bit syndromes that match the error pattern, the one with the smaller combination of bit syndromes is selected.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
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| CN108574565B (en) * | 2018-04-25 | 2024-05-31 | 四川省安道速博科技有限公司 | Signal quality detection device and method for S-mode transmitter |
| CN108737030B (en) * | 2018-05-17 | 2020-12-15 | 中国电子科技集团公司第五十四研究所 | A low-sensitivity receiving method for ADS-B signals based on spaceborne scenarios |
| CN110068340B (en) * | 2019-04-25 | 2020-08-18 | 电子科技大学 | Double-satellite time difference and frequency difference combined passive positioning device and method based on frequency compensation |
| CN111147411B (en) * | 2019-12-10 | 2022-06-28 | 北京航空航天大学杭州创新研究院 | A Dynamic Threshold Acquisition Method for Determining Confidence of ADS-B Signal Demodulation Results |
| CN111585639B (en) * | 2020-04-27 | 2021-05-04 | 上海航天计算机技术研究所 | Monitoring method and device for satellite-borne ADS-B message and storage medium |
| CN111896920B (en) * | 2020-05-27 | 2023-08-04 | 上海航天计算机技术研究所 | Configuration method of satellite-borne ADS-B load based on AD9361 |
| CN111988115B (en) * | 2020-08-31 | 2023-02-03 | 四川九洲空管科技有限责任公司 | ADS-B Distributed Processing System Based on Parallel Computing on General Platform |
| CN112468214B (en) * | 2020-11-13 | 2022-04-22 | 西安空间无线电技术研究所 | A kind of satellite-borne ADS-B group signal receiving and processing method |
| CN113114337B (en) * | 2021-03-25 | 2022-07-01 | 电子科技大学 | AIS baseband signal receiving system and method suitable for satellite-borne environment |
| CN113949486B (en) * | 2021-09-23 | 2023-10-20 | 武汉正维电子技术有限公司 | ADS_B signal analysis method and system based on symbol accumulation and correlation operation |
| CN114567340B (en) * | 2022-04-28 | 2022-07-12 | 成都和为时代科技有限公司 | ADS-B signal receiving baseband processing method and system based on correlation algorithm |
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| CN103401565B (en) * | 2013-07-09 | 2016-08-24 | 宁波成电泰克电子信息技术发展有限公司 | A kind of error correction and detection method of S mode ADS_B system |
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| CN104330774A (en) * | 2014-11-15 | 2015-02-04 | 安徽四创电子股份有限公司 | FPGA (Field Programmable Gate Array)-based S-mode secondary radar decoder and testing and error correction method thereof |
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