CN109541564B - Detection Method of Anti-jamming Performance of ADS-B Ground Station Based on Mean Filtering - Google Patents

Abstract

The invention discloses an ADS-B ground station anti-interference experiment verification method based on mean value filtering, which comprises the following steps of constructing an anti-interference antenna array; step two, establishing a wireless signal transmission model; step three, generating ADS-B simulated deception signals by the ADS-B transmitter; step four, 8 directional antennas receive ADS-B simulated deception signals, whether the deviation of the analyzed information and ADS-B information analyzed by an ADS-B receiver theory is within a set deviation range is analyzed and judged, if the deviation is within the set deviation range, the next step is carried out, and if not, alarm information is generated; step five, calculating a received signal strength RSSI value by adopting a wireless signal transmission model; step six, filtering the collected RSSI values; and step seven, comparing the RSSI value generated by the signal input by the directional antenna to determine whether alarm information is generated. When the invention is applied, whether the ADS-B ground station receiver can analyze and identify the deception jamming signal or not is conveniently judged, and the deception jamming resistance of the ADS-B ground station receiver can be further tested.

Description

Detection Method of Anti-jamming Performance of ADS-B Ground Station Based on Mean Filtering

technical field

The invention relates to aviation monitoring technology, in particular to a method for detecting anti-jamming performance of an ADS-B ground station based on mean filtering.

Background technique

ADS-B technology is the aviation surveillance technology mainly promoted by the International Civil Aviation Organization, and it is also one of the four new navigation technologies that my country's civil aviation is vigorously promoting at this stage. Standalone radar-based technological means changed to satellite-based surveillance technological means. As a mandatory technology, in the next few years, most of the airspace in the world will face the convenience that this new technology of ADS-B will bring us. At the same time, we must actively deal with ADS-B technology New challenges will be brought to us.

As a new type of aircraft surveillance technology under development, ADS-B technology has major security risks: ADS-B information can be forged, ADS-B information can be illegally received, and valid ADS-B information will be illegally interfered . These potential safety hazards can cause the ground air traffic control system and the airborne system of the aircraft to be interfered with by erroneous data, seriously affecting air traffic control and flight safety. Forging ADS-B information and interfering with ADS-B information, these illegal means bring serious safety hazards to flight safety that cannot be ignored. At present, international research on ADS-B anti-jamming and anti-spoofing is also in full swing.

The main function of the ADS-B ground station receiver is to complete the transmission and reception of ADS-B signals, which are divided into two parts: the transmitting channel and the receiving channel. The transmit channel includes units such as baseband interface, signal modulation, power amplification, power control, power detection, transmit detection, standing wave detection, and antenna presence detection; the receive channel includes low-noise amplification, local oscillator, frequency mixing, intermediate amplifier, demodulation, Baseband shaping and other units. At present, manufacturers and users at home and abroad are still intensively conducting a series of research on ADS-B ground station receivers. However, there is no corresponding test plan for the ability of ADS-B ground station receivers to resist spoofing jamming signals. To a certain extent, it affects the popularization and application of ADS-B technology.

Contents of the invention

The object of the present invention is to overcome the deficiencies in the prior art, and provides a kind of ADS-B ground station anti-jamming performance detection method based on mean filtering, it is convenient to judge whether ADS-B ground station receiver can resolve and identify cheating when it is applied It can test the anti-spoofing jamming ability of ADS-B ground station receiver.

The purpose of the present invention is mainly achieved through the following technical solutions: the ADS-B ground station anti-jamming performance detection method based on the mean value filtering comprises the following steps:

Step 1. Build an anti-jamming antenna array, the anti-jamming antenna array includes 8 parabolic directional antennas with a working frequency of 1090MHZ, and the 8 directional antennas are equally spaced on the same circumference, according to the included angle of 45° at intervals Build a 360° antenna array around a circle, and each directional antenna is connected to an ADS-B ground station receiver;

Step 2, establishing a wireless signal transmission model inside the ADS-B ground station receiver;

Step 3, control the ADS-B transmitter to be located within the receiving range of any directional antenna, and generate the ADS-B analog spoofing signal by the ADS-B transmitter;

Step 4, the 8 directional antennas all receive the ADS-B analog spoofing signal and transmit it to its corresponding ADS-B ground station receiver, and the ADS-B ground station receiver analyzes the received signal to obtain the signal containing The longitude and latitude data of the aircraft; judge whether the deviation between the analyzed ADS-B information and the ADS-B information analyzed by the ADS-B receiver theory is within the set deviation range, and if it is within the set deviation range, go to the next step ; Otherwise, the ADS-B ground station receiver generates an alarm message;

Step 5, using the wireless signal transmission model to calculate the received signal strength RSSI value;

Step 6. Filtering the collected RSSI values by means of mean value filtering;

Step 7. Transmit the RSSI values generated by the input signals of all directional antennas to any ADS-B ground station receiver, and judge whether the RSSI values generated by the input signals of the directional antennas within the receiving range of the directional antenna where the ADS-B transmitter is located are Greater than the RSSI value generated by the input signal of other directional antennas, if greater, no alarm information will be generated; otherwise, the ADS-B ground station receiver will generate alarm information.

ADS-B message information includes: aircraft ID and type message, air position message, ground position message, air speed message, aircraft status and status message, aircraft operating status message, test message, ground system status message, route change message, extension Intermittent oscillation aircraft identity message, etc. The deviation range between the ADS-B information analyzed by the ADS-B ground station receiver adopted in the present invention and the ADS-B information analyzed theoretically by the ADS-B receiver is set according to the actual detection environment. The present invention analyzes the received radio signal through the ADS-B ground station receiver connected with the directional antenna system, if the ADS-B information deviation that is correct and analyzed with the ADS-B receiver theory is within If it is within the set deviation range, it indicates that the signal received by the present invention is an acceptable signal. Otherwise, if the present invention does not receive the ADS-B information or the deviation between the received ADS-B information and the ADS-B information analyzed theoretically by the ADS-B receiver is not within the set deviation range, then the information is not available signal of.

The present invention sets up a plurality of directional antennas, adopts the space angle domain to divide the virtual channel to carry out the method of space diversity control, namely Space Division Multiple Access SDMA (Space Division Multiple Access), also known as multi-beam frequency multiplexing, by marking different azimuths The antenna beams of the same frequency are used for frequency multiplexing. The invention analyzes the ADS-B spoofed signal through the space division multiple access SDMA technology.

The antenna has different radiation or receiving capabilities for different directions in space, which is the directivity of the antenna. There are two types of antennas, omnidirectional and directional, depending on the directionality. The necessary facilities to realize space division multiple access technology are directional antennas. Directional antenna refers to an antenna that transmits and receives electromagnetic waves particularly strongly in one or several specific directions, while transmitting and receiving electromagnetic waves in other directions is zero or extremely small. Compared with the omnidirectional antenna used in the traditional ADS-B system, the purpose of using a directional transmitting antenna is to increase the effective utilization of radiation power and increase confidentiality; the main purpose of using a directional receiving antenna is to enhance signal strength and increase anti-interference ability.

The purpose of the verification experiment of the present invention is to decode the same signal in different directions by the ADS-B ground station receiver, obtain the aircraft latitude and longitude data contained in the signal, and obtain the RSSI value (Received Signal Strength Indication) of the signal in different directions simultaneously , received signal strength indication), and then compare the RSSI value to determine the validity of the aircraft latitude and longitude data contained in the signal. Among them, RSSI is an optional part of the wireless transmission layer, and is used to determine the link quality. It can be obtained in every data transfer, without additional bandwidth and energy, and without additional hardware costs. However, due to the complex environment in which sensor nodes are deployed, the receiving strength of the signal will be affected by multipath effects, non-line-of-sight and antenna gain, which will significantly change the propagation loss of the signal, resulting in a large error when obtaining distance information. . Therefore, in order to obtain a better positioning effect through the RSSI method, it is necessary to eliminate the error in the RSSI ranging process as much as possible. In order to reduce the error, the present invention first filters out the data with low probability by means of mean value filtering, and then calculates the average value, thus avoiding the influence of these data with small probability and large interference, thereby improving the accuracy.

Further, the formula for calculating the received signal strength RSSI value using the wireless signal transmission model in the step five is as follows:

RSSI＝A-10nlogd+ _XdB

Among them, RSSI is the received signal strength, A is the RSSI value at one meter, n is the path loss index, d is the measurement distance, and X _dB is a Gaussian random variable.

Further, m data are collected in the step six, and then their average value is calculated, and the formula is as follows:

Wherein, the value of i is an integer between 1 and m, which is the ith sampling. In this way, when the present invention is applied, data is sampled m times to filter out low-probability events, thereby achieving the purpose of improving accuracy.

Further, the directional antenna is a directional cut grid parabolic antenna with a working frequency of 1.1G±0.1 and an antenna gain of 15dBi.

In summary, the present invention has the following beneficial effects compared with the prior art: (1) the principle of the verification experiment of the present invention is realized based on the wireless signal propagation model and error analysis, by laying 8 directional antennas to form an antenna array, And generate ADS-B analog spoofing signal through ADS-B transmitter. The invention verifies the azimuth of the radio wave signal sent by the information source, ensures the consistency between the signal source and the information content, and prevents other ADS-B signals from affecting the implementation of the invention by verifying the consistency of the incoming wave direction of the ADS-B signal. The present invention can identify the external interference source affecting the ADS-B ground station receiver, and achieve the purpose of verifying whether the ADS-B ground station receiver can analyze and identify the ADS-B analog spoofing signal generated by the ADS-B transmitter. It is convenient to test its ability to resist deceptive jamming.

(2) the present invention is the parabolic directional antenna of 1090MHZ by setting 8 operating frequencies, each directional antenna is correspondingly connected with an ADS-B ground station receiver, can increase the analysis data volume of the present invention, and then can guarantee the present invention Verify accuracy.

Description of drawings

The drawings described here are used to provide a further understanding of the embodiments of the present invention, constitute a part of the application, and do not limit the embodiments of the present invention. In the attached picture:

Fig. 1 is the flowchart of a specific embodiment of the present invention;

Figure 2 shows the RSSI value of 300 times of sending and receiving at 1m.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the examples and accompanying drawings. As a limitation of the present invention.

Example:

As shown in Figure 1, the ADS-B ground station anti-jamming performance detection method based on mean filtering includes the following steps in sequence: Step 1, build an anti-jamming antenna array; Step 2, establish a wireless signal transmission model; Step 3, generate ADS-B simulates a spoofing signal; step 4, judge whether the deviation between the ADS-B information analyzed and the ADS-B information analyzed theoretically by the ADS-B receiver is within the set deviation range, if it is within the set deviation range, then Go to the next step, otherwise an alarm message will be generated; step five, use the wireless signal transmission model to calculate the received signal strength RSSI value; step six, use the mean value filter to filter the collected RSSI value; step seven, judge the coverage Whether the RSSI value generated by the directional antenna of the ADS-B transmitter is greater than the RSSI value generated by other directional antennas, if so, end, otherwise generate an alarm message.

Step 1 of this embodiment specifically includes the following steps: building an anti-jamming antenna array, wherein the anti-jamming antenna array includes 8 parabolic directional antennas with a working frequency of 1090MHZ, and the 8 directional antennas are equally spaced on the same circle, according to the interval A 45° included angle is used to build a 360° antenna array around a circle, and each directional antenna is connected to an ADS-B ground station receiver. The wireless signal transmission model established in step 2 of this embodiment is a Shadowing model, which is established inside the receiver of the ADS-B ground station. When step three of this embodiment is implemented, the ADS-B transmitter is first controlled to be within the receiving range of any directional antenna, and then the ADS-B transmitter generates an ADS-B analog spoofing signal.

Step 4 of the present embodiment is in concrete implementation, and the 8 directional antennas all receive the ADS-B analog spoofing signal and transmit it to its corresponding ADS-B ground station receiver, and the ADS-B ground station receiver analyzes the received signal , to get the latitude and longitude data of the aircraft contained in the signal. Then, it is judged whether the deviation between the ADS-B information analyzed and the ADS-B information analyzed theoretically by the ADS-B receiver is within the set deviation range, and if it is within the set deviation range, then enter the next step; otherwise , an alarm message is generated by the ADS-B ground station receiver.

Step 5 of the present embodiment is implemented in detail, and the formula for calculating the received signal strength RSSI value using the wireless signal transmission model is as follows:

RSSI＝A-10nlogd+ _XdB

Among them, RSSI is the received signal strength, A is the RSSI value at one meter, n is the path loss index, and the path loss index is usually measured by a specific site, generally between 2 and 6. d is the measurement distance, and X _dB is a Gaussian random variable without any meaning.

Collect m data in the step 6 of the present embodiment, then calculate its average value, the formula is as follows:

Wherein, the value of i is an integer between 1 and m, which is the ith sampling.

Figure 1 shows the RSSI value obtained by sending and receiving 300 times when the distance between the sending node and the receiving node is 1m. Since the RSSI value is easily affected by environmental factors, resulting in relatively large errors, in order to obtain a relatively stable RSSI value, this embodiment performs filtering processing on it first.

Step 7 of the present embodiment is in concrete implementation: transmit the RSSI value that all directional antennas input signals produce to any one ADS-B ground station receiver, judge the directional antenna within the directional antenna receiving range where ADS-B transmitter is located Whether the RSSI value generated by the input signal is greater than the RSSI value generated by the input signal of other directional antennas, if it is greater, no alarm information will be generated; otherwise, the ADS-B ground station receiver will generate alarm information.

The ADS-B ground station receiver system performance that present embodiment adopts is as shown in table 1:

Table 1 ADS-B ground station receiver system performance

In order to verify the anti-interference performance of the ADS-B ground station receiver, there must be an interference source available for experimental detection. In this embodiment, the ADS-B transmitter generates an ADS-B analog spoofing signal. The system composition of the ADS-B transmitter includes data transmitter, GNSS receiver, signal processor and information processor and other hardware modules, which broadcast key data such as the attitude, position, speed and acceleration of the carrier itself. The ADS-B transmitter of this embodiment is used as a transmitting device, and various parameters of the analog signal can be realized through its open interface. The ADS-B transmitter system performance that present embodiment adopts is as shown in table 2:

Table 2 ADS-B transmitter system performance

serial number category performance requirements 1 transmit power ≥37dBm 2 working frequency 1090MHz±1MHz 3 Standards compliant DO-260B 4 Encoding format DF17/DF18 5 positioning accuracy Better than 10m (95% confidence level) 6 positioning update rate 5Hz 7 Data interface RS232 serial port 8 Working power internal rechargeable battery 9 Operating temperature 10～40℃

The directional antenna performance parameters of the present embodiment are as shown in Table 3:

Table 3 Directional antenna performance parameters

The directional antenna of this embodiment is a directional cutting grid parabolic antenna with a working frequency of 1.1G ± 0.1 and an antenna gain of 15dBi. The antenna is a die-cast aluminum reflective grid with an anti-ultraviolet aging coating. Polarized or horizontally polarized mounts come standard with adjustable angle swivel clips for wireless remote transmission.

The ADS-B ground station receiver output information of the present embodiment comprises: receiver serial number, signal strength, target ICAO address, call sign, longitude, latitude, speed, height and course; All information all adopts ASCII frame transmission, and the data of every frame Separate items with commas.

The 8 ADS-B ground station receiver numbers of this embodiment are 01, 02, 03, 04, 05, 06, 07 and 08 respectively; -08 for numbering, ADS-B ground station anti-jamming corresponds to the directional antenna of the corresponding number. A specific example of anti-interference verification when this embodiment is applied is as follows:

The location of this experiment is Guanghan Airport, and the coordinates of the receiving station are 30.94842N, 104.32194E. In this experiment, we independently decode the signal of the ADS-B transmitter, and verify the validity of the signal through the RSSI value.

The first is to conduct an RSSI comparison test on the actual position signal of the ADS-B transmitter. The ADS-B transmitter is located within the receiving range of the No. 01 directional antenna, and eight ADS-B ground station receivers decode and process the signal respectively. The decoded data is:

MSG,01,-6.52,FFAABB,TESTADSB,104.22187,31.46842,1450,320,000;

MSG,02,-9.11,FFAABB,TESTADSB,104.22187,31.46842,1450,320,000;

MSG,03,-11.56,FFAABB,TESTADSB,104.22187,31.46842,1450,320,000;

MSG,04,-13.67,FFAABB,TESTADSB,104.22187,31.46842,1450,320,000;

MSG,05,-18.21,FFAABB,TESTADSB,104.22187,31.46842,1450,320,000;

MSG,06,-13.24,FFAABB,TESTADSB,104.22187,31.46842,1450,320,000;

MSG,07,-10.91,FFAABB,TESTADSB,104.22187,31.46842,1450,320,000;

MSG,08,-8.97,FFAABB,TESTADSB,104.22187,31.46842,1450,320,000;

The ICAO address of the ADS-B transmitter is FFAABB, the call sign is TESTADSB, the longitude is 104.22187, the latitude is 31.4684, the altitude is 1450 feet, the course is 320°, and the speed is zero. The obtained RSSI values of each ADS-B ground station receiver channel are shown in Table 4:

Table 4 RSSI value of each ADS-B ground station receiver channel before correction

aisle 01 02 03 04 05 06 07 08 RSSI -6.52 -9.11 -11.56 -13.67 -18.21 -13.24 -10.91 -8.97

It has been verified that the actual position of the ADS-B transmitter is consistent with the decoded position of the signal, and the RSSI ₀₁ is greater than the RSSI values of other channels. It can be judged that the signal is a valid signal, so the system displays normally and no alarm information appears.

Next, set the simulated coordinates of the ADS-B transmitter. The actual position of the ADS-B transmitter does not change. The simulated coordinates are corrected to be within the receiving range of the No. 05 directional antenna. Eight ADS-B ground station receivers decode and process the signals respectively. The decoded data is

MSG,01,-6.58,FFAABB,TESTADSB,104.22187,31.46842,1450,320,000;

MSG,02,-9.04,FFAABB,TESTADSB,104.22187,31.46842,1450,320,000;

MSG,03,-11.41,FFAABB,TESTADSB,104.22187,31.46842,1450,320,000;

MSG,04,-12.97,FFAABB,TESTADSB,104.22187,31.46842,1450,320,000;

MSG,05,-18.2,FFAABB,TESTADSB,104.22187,31.46842,1450,320,000;

MSG,06,-12.84,FFAABB,TESTADSB,104.22187,31.46842,1450,320,000;

MSG,07,-11.51,FFAABB,TESTADSB,104.22187,31.46842,1450,320,000;

MSG,08,-8.93,FFAABB,TESTADSB,104.22187,31.46842,1450,320,000;

The RSSI values of each ADS-B ground station receiver channel obtained after correction are shown in Table 5:

Table 5 The RSSI value of each ADS-B ground station receiver channel after correction

aisle 01 02 03 04 05 06 07 08 RSSI -6.58 -9.04 -11.41 -12.97 -18.2 -12.84 -11.51 -8.93

It can be seen that because the actual position of the ADS-B transmitter is inconsistent with the decoded position of the signal, if the real position of the signal is the decoded position, it should be RSSI ₀₅ , but the actual situation is RSSI ₀₁ , so the actual position of the signal can be judged The location should be within the receiving range of the No. 01 directional antenna, so the system generates an alarm message for this signal.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the scope of the present invention. Protection scope, within the spirit and principles of the present invention, any modification, equivalent replacement, improvement, etc., shall be included in the protection scope of the present invention.

Claims (4)

1. The ADS-B ground station anti-interference performance detection method based on mean value filtering is characterized by comprising the following steps:

the method comprises the steps that firstly, an anti-interference antenna array is built, the anti-interference antenna array comprises 8 parabolic directional antennas with the working frequency of 1090MHZ, the 8 directional antennas are distributed on the same circumference at equal intervals, an antenna array which surrounds the circumference to form 360 degrees is built according to an included angle of 45 degrees, and each directional antenna is correspondingly connected with an ADS-B ground station receiver;

step two, establishing a wireless signal transmission model in the ADS-B ground station receiver;

step three, controlling the ADS-B transmitter to be positioned in the receiving range of any one directional antenna, and generating an ADS-B simulated deception signal by the ADS-B transmitter;

step four, 8 the directional antennas receive ADS-B simulated deception signals and transmit the ADS-B simulated deception signals to corresponding ADS-B ground station receivers, and the ADS-B ground station receivers analyze the received signals to obtain airplane longitude and latitude data contained in the signals; judging whether the deviation of the analyzed ADS-B information and the ADS-B information analyzed by the ADS-B receiver theory is within a set deviation range, and entering the next step if the deviation is within the set deviation range; otherwise, generating alarm information by the ADS-B ground station receiver;

step five, calculating a received signal strength RSSI value by adopting a wireless signal transmission model;

step six, filtering the collected RSSI values by adopting a mean value filtering mode;

step seven, transmitting RSSI values generated by signals input by all the directional antennas to any ADS-B ground station receiver, judging whether the RSSI values generated by the signals input by the directional antennas in the receiving range of the directional antennas where the ADS-B transmitters are located are larger than the RSSI values generated by the signals input by the other directional antennas, and if so, not generating alarm information; otherwise, generating alarm information by ADS-B ground station receiver.

2. The ADS-B ground station anti-interference performance detection method based on mean value filtering of claim 1, wherein the formula for calculating the received signal strength RSSI value by using the wireless signal transmission model in the fifth step is as follows:

RSSI＝A-10nlogd+X _dB

wherein RSSI is the received signal strength, n is the path loss exponent, d is the measurement distance, X _dB Are gaussian random variables.

3. The ADS-B ground station anti-interference performance detection method based on mean value filtering of claim 1, wherein m data are collected in the sixth step, and then an average value is obtained, wherein the formula is as follows:

wherein, the value of i is an integer between 1 and m and is the ith sampling.

4. The ADS-B ground station anti-interference performance detection method based on mean value filtering of any one of claims 1-3, wherein the directional antenna is a directional cutting grid parabolic antenna with an operating frequency of 1.1G +/-0.1 and an antenna gain of 15 dBi.

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