If c is D₄D₂D₁Decoded result D when being one of 1,2,3,5,6,7, be judged to be the A schema code, end of identification when the result is one of 0,4, carries out next step;

The 3rd step: classification processing is carried out in the position by signal receiver, near receiver is positioned at the airport during 50km scope, is undertaken by near the recognition rule in the landing zone airport, otherwise carries out according to the recognition rule in air route/airline operation zone;

Near the 4th step: the recognition rule in the landing zone airport: behind answer codes of each acquisition, compare with the code listing of safeguarding:

(1) the adaptability number of times appears more than 3～5 times if the code of current acquisition is stable; Think that then this answer codes is constant code; This code is pressed C pattern rules decodings, if the decoding height thinks that then this code is a C pattern height code when 5100 meters～14900 meters of CAAC's regulation height layer scope (table 3); Otherwise think that this code is an A pattern height, end of identification;

(2), then deposit in and safeguard code listing as code undetermined if be new code;

(3) code listing safeguarded of each the adaptive processing cyclic check in 3～4 seconds to only receiving 1～2 time answer codes, is judged to be the C schema code, and confirms end of identification according to C schema code decoding rule;

The 5th step: the recognition rule in air route/airline operation zone: the height layer corresponding codes according to table 3 detects:

(1) if the code of receiving not in the scope of 5100 meters～14900 meters the height layer that CAAC stipulates (table 3), is then thought the A schema code, end of identification, otherwise got into for the 5th step (2);

(2) judge according to the flight course rule of C pattern height and aircraft; For example: the ABCD code of receiving is 5734 o'clock; Obtaining by the C mode decoding is at 11000 meters height layers; When if the heading of these other aircrafts of height layer and the direction of this target are inconsistent, think that then this code is A schema code rather than C schema code; Otherwise, think that it is the C schema code, end of identification.

The invention has the beneficial effects as follows: the present invention is directed to multipoint positioning etc. and send signal and realize in the technology of passive positioning, how to distinguish the code classification that airborne answering machine sends and invent through receiving airborne answering machine.This technological invention begins from the composition analysis of answer signal pulse; And combination real flight conditions; Carry out the recognition technology of A schema code and C schema code; Carry out signal sorting and identification provides useful help for the center processing station of multipoint location system, effectively improved the signal recognition efficiency and the bearing accuracy of multipoint location system, have bigger application prospect and use value.

Description of drawings

Fig. 1 is an A/C pattern answer codes sequence synoptic diagram of the present invention.

Embodiment

The airborne A/C pulse code rule of replying:

Technical scheme of the present invention is to analyze the A schema code that answering machine sends and the physical significance of C pattern height, uses clear and definite recognition rule and carries out class discrimination, thereby obtain final discriminator.Below describe the used substance of identification in detail.

A schema code that airborne answering machine is sent and C pattern height pulse train are as shown in Figure 1.

All information pulses are included between F1 pulse and the F2 pulse, and F1 and F2 are called as the framework pulse, and the SPI pulse is the position that is positioned at 4.35 microseconds after the F2 pulse, only appears in the A schema code, and the pilot is provided with answering machine as required and whether sends this pulse.Each information pulse width in the framework pulse is 0.45 microsecond, and continuous two rising edge of a pulses are at a distance of 1.45 microseconds.The framework pulse all must occur in replying at every turn, and other pulses then change according to information is different.Middle X pulse is subsequent use pulse, and perseverance is 0.

The coding rule of response message pulse at present is:

(1) A pattern answer codes coding rule:

12 A pattern-recognition codes that airborne equipment is replied have been divided into 4 groups, promptly go up the ABCD among Fig. 1, and every group by 3 pulses, and subscript is respectively 1,2,4, and the expression weight is exactly the octal numeral by three pulse bit representations.The order of 12 information from a high position to the low level is: A₄A₂A₁B₄B₂B₁C₄C₂C₁D₄D₂D₁

When being scale-of-eight 6571 like the A schema code, its expression A group is 6, by A₂And A₄Information code element is formed, and the B group is 5, by B₁And B₄Code element is formed, and the C group is 7, by C₁, C₂And C₄Code element is formed, and the D group is 1, by D₁Code element is formed, and the pulse train of its appearance is as shown in table 1:

The pulse train of table 1A schema code 6571 is formed

F1	C1	A1	C2	A2	C4	A4	X	B1	D1	B2	D2	B4	D4	F2
															1	1	0	1	1	1	1	0	1	1	0	0	1	0	1

Simultaneously in the A schema code, also stipulated three special codes, had special implication, be respectively: 7500 expression aircrafts such as are kidnapped at illegal interference the, 7600 expression aircraft communication faults, emergencies such as 7700 expression aircraft fuels, machinery.

(2) C pattern height code coding rule:

C pattern height code coded sequence from high to low is: D₁D₂D₄A₁A₂A₄B₁B₂B₄C₁C₂C₄, wherein high 9 employings be standard cycle coding (Gray code) rule, least significant bit (LSB) representes highly to be 500ft, low 3 is five loop cycle sign indicating number coding rules, least significant bit (LSB) representes highly to be 100ft.

According to the reflected code coding rule, work as D₁The position is 1 o'clock, and the height of expression has surpassed the flying height of aircarrier aircraft more than 30000 meters, therefore D in the airborne answer signal of Civil Aviation System₁The position is 0.

Low 3 five loop cycle sign indicating number coding rules are as shown in table 2.

Low 3 the five loop cycle sign indicating number coding rules of table 2C pattern response message

The airborne A/C pulse recognition of replying:

According to the A/C mode pulse coding rule that aforementioned airborne answering machine is sent, the present invention starts with from coding rule, and combines the aerospace applications environment, proposes following A/C pulse recognition code:

(1) with the framework pulse internal information pulse of receiving, big-endian is according to A₄A₂A₁B₄B₂B₁C₄C₂C₁D₄D₂D₁Series arrangement, promptly extract according to the order of A schema code; And check whether the SPI pulse occurs, if the SPI pulse occurs, then is judged to be the A schema code, end of identification, otherwise got into for (2) step;

(2) decoding according to A schema code decoding rule, if the ABCD decoded result thinks that this information code is an A pattern-recognition code when being one of 7500,7600,7700, and is special code;

(3) decode according to A schema code decoding rule, if C₄C₂C₁Decoded result when being one of 0,5,7, then think this information code be A pattern-recognition code (according to last table 2, C in the C pattern height code₄C₂C₁Decoded result can only be 1,2,3,4, one of 6);

(4) decode according to A schema code decoding rule, if D₄D₂D₁Decoded result when being one of 1,3,5,7, think that then this information code is the A pattern-recognition code (D of C pattern height code₁The position is 0); Shown in following table 3, at air route/course sector, as long as D₄D₂D₁Decoding when being one of 0,4, just be the C schema code, other situation are the A schema code;

(5) be near air route airline operation regional (other zones) outside landing zone (is center radius 50km like the airport) and the airport airport with area dividing.Aircraft is in the landing stage in the landing zone near the airport, and the A schema code that its answering machine is sent immobilizes, and the C schema code is the variation that does not stop; The control zone in the course line, air route; The A schema code of target and C pattern height; Generally can not change; C pattern height can take place to change among a small circle when running into situation such as inclement weather, and in addition C pattern height then is the height layer flight in regulation, and the above flight level of 5000m that CAAC delimit is as shown in table 3 below:

Table 3 CAAC delimit above flight level of 5000m and corresponding height made in Great Britain and coding

(6) near the landing zone airport and air route airline operation dividing region method: the position with the ground receiver that receives airborne answer signal is judged; In the time of promptly in the ground receiver is in the scope that the airport is center radius 50km; Its signal of receiving carries out according near the landing zone A/C pattern recognition rule airport, otherwise carries out according to air route airline operation zone A/C pattern recognition rule.

(7) A/C mode signal recognition rule near the landing zone, airport: behind answer codes of each acquisition; Compare with the existing code listing of safeguarding; Occur more than the adaptability number of times (3～5 times) if this code is stable; Think that then this answer codes is constant code, need to go on foot and discern differentiation, safeguard code listing otherwise deposit in as code undetermined by following (8).Each adaptive processing cycle (in 3～4 seconds) is checked the answer codes that those only receive 1～2 time, because of in the landing level interval being changes constantly, can judge that these codes are the C schema code, and confirms according to C schema code decoding rule.

(8) to landing zone (is in the scope of center radius 50km with the airport) near the airport, when receiving stable answer codes continuously, two kinds of situation are arranged: one of which is the A schema code, and it is two for leaping the overhead C schema code in this airport.Recognition rule to both of these case is: stable code is pressed the decoding of C pattern rules, if the decoding height is thought that then this code is a C pattern height code, otherwise thought that this code is an A pattern height when the height layer scope (5100 meters～14900 meters) of table 3.

(9) air route airline operation zone A/C mode signal recognition rule: the height layer corresponding codes according to table 3 detects, if the code of receiving is then thought the A schema code not in the scope of table 3; Otherwise the flight course rule according to C pattern height and aircraft is judged; For example: the ABCD code of receiving is 5734 o'clock; Obtaining by the C mode decoding is at 11000 meters height layers; When if the heading of these other aircrafts of height layer and the direction of this target are inconsistent, think that then this code is A schema code rather than C schema code, otherwise think that it is the C schema code.

Claims

1. the recognition methods of an airborne answering machine A/C pattern answer signal, the practical implementation step is following:

Second step: decode by the A pattern rules,

Near the recognition rule in the landing zone airport: behind answer codes of each acquisition, compare with the code listing of safeguarding:

(1) the adaptability number of times appears more than 3～5 times if the code of current acquisition is stable; Think that then this answer codes is constant code; This code is pressed C pattern rules decodings, if the decoding height thinks that then this code is a C pattern height code when 5100 meters～14900 meters of CAAC's regulation height layer scope; Otherwise think that this code is an A pattern height, end of identification;

The recognition rule in air route/airline operation zone: the height layer corresponding codes according to table 3 detects:

(4) if the code of receiving not in the scope of 5100 meters～14900 meters the height layer that CAAC stipulates, is then thought the A schema code, end of identification, otherwise got into for the 3rd step (5);

(5) judge according to the flight course rule of C pattern height and aircraft: the ABCD code to receiving obtains the height layer corresponding to table 3 by the C mode decoding; When if the heading of these other aircrafts of height layer and the direction of this target are inconsistent, think that then this code is A schema code rather than C schema code; Otherwise, think that it is the C schema code, end of identification;

Above-mentioned table 3 is: