CN101137226A - Single antenna terminal direction-finding method - Google Patents

Abstract

The invention discloses a monopole antenna terminal direction-finding method, relates to wireless communication technology field. The method aims at difficult extracting of positional parameters in practical application, utilizes antenna information of present mobile communication network, establishes antenna gain difference and signal arrival angle corresponding list; through measuring received pilot frequency intensity difference, calculating field strength difference value of pilot signals on a handheld terminal, according to the field strength difference value finding antenna gain difference and signal arrival angle corresponding list to get AOA parameters, the direction-finding is finished. The method has the advantages of good secrecy, without occupying special channel expense, simple operation, without need of antenna change. The invention can be widely used for positioning of mobile terminal, especially for terminal positioning in military field.

Description

Single antenna terminal direction-finding method

Technical field

The present invention relates to wireless communication technology field, relate in particular to wireless positioning field, specifically is to realize from the direction finding function in the single antenna handheld terminal.

Background technology

Along with the development of mobile communication, location-based service (LBS) more and more is subject to people's attention.This business relates to numerous areas such as traffic, logistics, public security, emergency and daily life, numerous business such as navigation, logistics management, transport information, schedule can be provided, use very extensively, will reach 11,700,000,000 dollars according to the business revenue that predicts global LBS in 2008.

Traditional localization method of realizing LBS is mainly by measuring the time of advent (TOA), and the time of advent poor (TDOA), observed time difference (OTD) arrives the location of angle (AOA) and GPS assist location methods such as (AGPS) realization to portable terminal.For said method, obtaining of various parameters is the key of location algorithm.In traditional localization method, there is following problem:

A. the obtaining of TDOA positional parameter based on terminal needs three and above base station transmit signals of not standing altogether synchronously; Based on network TDOA location algorithm, three of needs and above base station of not standing altogether synchronously thereof obtain transmitting of terminal.In this case, the location probability is very low.

B. in the TOA of terminal location algorithm, need two and above base station transmit signals of not standing altogether synchronously; Based on network TOA location algorithm, two of needs and above base station of not standing altogether synchronously thereof obtain transmitting of terminal.In this case, require terminal and base station synchronization, Fa She signal has time tag simultaneously, estimates so that terminal is finished TOA.

The C.OTD localization method applies to the locating measurement method of asynchronous base station, and this method needs three and above base station equally, and the location probability is lower.

D. traditional AOA localization method all is to realize at network side, and can not realize in end side.Need two and above antenna or smart antenna to finish direction finding at network side to terminal.On dedicated channel, the direction finding parameter is sent to terminal to terminal by network then, perhaps finish the location computing and by dedicated channel positioning result is sent to terminal then by network.These two kinds of methods all need to take dedicated channel and Internet resources.The hidden danger that exists terminal location to divulge a secret simultaneously.

E. AGPS uses satellite and Cellular Networks mixed positioning, and positioning accuracy is higher, but needs repeatedly Network Transmission in the position fixing process, occupies the air traffic channel resource in a large number.Because handheld terminal need be searched for satellite-signal, has increased power consumption, has reduced stand-by time.AGPS need increase the GPS receiver on handheld device simultaneously, has increased use cost.

Because in areas such as wilderness or seabeaches, be difficult to capture a plurality of signal of base station sometimes, this makes first three methods have application limit, and adopt the method for AOA and TOA combination to finish at single base station, the scope of application is wider.Therefore research realizes that to portable terminal the method for location is necessary by obtaining the AOA parameter.

The main approaches of terminal direction-finding technology is included in terminal and uses many antennas and smart antenna.These two kinds of methods all need terminal antenna is transformed, the volume of terminal and the complexity of structure have been increased, its enforcement difficulty is also bigger simultaneously, and particularly smart antenna is difficult under the current components and parts condition and uses smart antenna to finish the direction finding function in terminal because operand is very big.

Summary of the invention

The present invention is directed to AOA localization method traditional in the prior art can only realize at network side, need take dedicated channel and Internet resources, the terminal location defective of hidden danger such as divulge a secret easily, a kind of direction finding function that realizes the single antenna handheld terminal under the less occasion in single base station or base station based on the AOA parameter is proposed, at prior art AOA difficult extracting of positional parameters in actual applications, the present invention proposes a kind of software or the less single antenna direction-finding method of hardware costs is realized finishing the self-align of terminal from direction finding.

The technical scheme that the present invention solves the problems of the technologies described above is for proposing a kind of single antenna terminal direction-finding method based on positional parameter AOA, after specifically comprising the steps: the handheld terminal access network, obtain the base station identity code Base ID of serving BS and the pilot offset Pilot-PN of serving sector by network acquisition descending pilot frequency and broadcast channel; When handheld terminal receive need finish direction finding and positioning instruction after, from the information table that is stored in terminal memory or obtain the gain table and the antenna direction information of serving BS fan antenna by the common signal channel of system; Handheld terminal utilizes antenna gain and antenna direction information to set up gain difference and antenna direction correspondence table; By increasing the reference signal length of handheld terminal, adjust the received signal treated length, catch other sector pilot signals of serving BS, obtain corresponding pilot offset; Computing module carries out related calculation with the pilot offset of the terminal received signal serving sector consistent with phase of received signal, obtains signal peak, determines three sector pilot signal strengths that receive thus; Field intensity difference value according to pilot signal strength differentiate frequency signal.Direction finding module is then searched the gain difference and the direction correspondence table of storing in the memory according to pilot signal field intensity difference value and is determined the direction that signal arrives, and finishes direction finding.

Serving BS adopts three sector configuration, has the directional antenna of 120 ° of deflections, and each fan antenna points to fixing.

When the AOA of capture terminal base station transmit signals, can obtain the positional information of serving BS, the pilot offset of sector by common signal channel, obtain function-pilot signal strength about signal propagation direction θ, search the gain difference and the direction correspondence table of storing in the memory according to pilot signal field intensity difference value and determine the direction that signal arrives, simultaneously can be according to the propagation time (TOT-Time of Transmit) of pilot channel estimation terminal to base station, to realize the self-align of terminal.The hardware that this method does not need existing terminal to be carried out antenna is changed, and does not also need to change for base station side, more need not increase dedicated channel and send corresponding information.

Therefore, the single antenna terminal direction-finding method that adopts the present invention to propose based on positional parameter AOA, save channel and Internet resources, all need not the extra hardware device that is used for the direction finding computing that increases at network side and end side, need on channel, not transmit locating information (as AOA or TOA), eliminate the channel that terminal positional information is divulged a secret, guaranteed the fail safe of terminal.

Description of drawings

Figure 1 shows that the single antenna terminal direction-finding method flow chart

Figure 2 shows that terminal receives the pilot signal schematic diagram

Embodiment

Terminal direction-finding method of the present invention is finished in the handheld terminal side with single antenna, handheld terminal is obtained information such as relevant serving BS of direction finding and pilot signal from channel or terminal memory by information acquisition module, the control treatment module received signal is carried out relevant treatment and is carried out the calculating of pilot signal field intensity and difference etc. by computing module, the direction finding module is finished terminal direction-finding function of the present invention according to gain difference of storing in the result of calculation inquiry terminal memory and direction correspondence table.

At the drawings and specific embodiments realization of the present invention is described specifically below.

Figure 1 shows that and adopt the single antenna terminal direction-finding method flow chart based on AOA of the present invention, specifically comprise the steps:

1. behind the handheld terminal access network, terminal is carried out initialization, acquisition module obtains the base station identity code Base ID of serving BS and the pilot offset Pilot-PN of serving sector by network acquisition downlink pilot frequency channel and broadcast channel, obtain serving BS fan antenna gain table and antenna direction information, and it is stored in the handheld terminal memory.

2. start the direction finding function, the user to the terminal input command, starts the direction finding and the positioning function of direction finding module by man-machine interfaces such as keyboards.

3. the list information in the terminal inquiry module searches memory obtains serving BS fan antenna gain table and antenna direction information, and perhaps the common signal channel by system directly obtains above-mentioned information.

4. control treatment module is utilized antenna gain table and antenna direction information architecture gain difference and direction correspondence table, deposits in the terminal memory.

5. terminal control treatment module adjustment, reference signal and received signal treated length, acquisition module are caught other sector pilot signals of serving BS, determine corresponding pilot offset.

6. after acquisition module captures other two sector pilot signals of serving BS, utilize the pilot offset of three sectors to calculate the pilot signal strength that three sectors receive.

7. computing module is according to the field intensity difference value of pilot signal strength differentiate frequency channel.

8. gain difference and direction correspondence table that direction finding module is searched in the memory according to pilot signal field intensity difference value are determined the direction that signal arrives.

Be illustrated in figure 2 as terminal and receive the pilot signal schematic diagram, localization method of the present invention is realized based on single base station, use three sector configuration in the base station of network side, three directional antennas with 120 ° of deflections are set up in each base station, in base station construction, adopt unified antenna, the gain diagram of each antenna horizontal direction is identical or known, guarantees that the sensing of three antennas is fixed, and the angle of declination of three antennas is all identical with antenna performance simultaneously.

Suppose that handheld terminal is positioned at sector G, at first captures the pilot signal of sector G.By increasing received signal treated length, reference signal length, catch all the other sector A of serving BS and the pilot signal of sector B then.Handheld terminal can come into effect the direction finding function after capturing other sector pilot signals of serving BS.

1. terminal is obtained the pilot signal and the base station information of serving sector by pilot tone and broadcast channel

Behind the handheld terminal access network, acquisition module scans downlink pilot frequency channel and broadcast channel, selects the strongest sector of pilot tone as serving sector.Capture the pilot signal of serving sector when handheld terminal after, the handheld terminal demodulation module demodulates the base station identity code Base ID of serving BS in the broadcast channel information and the pilot offset Pilot-PN of serving sector etc.Unique Base ID is only distributed in each sector, and each pilot tone also has Pilot-PN one to one.

2. obtain fan antenna gain and directional information

Serving BS issues base station position information, antenna gain information, antenna direction information by common signal channel, perhaps corresponding information is stored in the handheld terminal memory in advance.Handheld terminal obtains information such as antenna direction, antenna gain: the handheld terminal information acquisition module is by gathering the information that common signal channel sends, and perhaps searches in the canned data from terminal memory according to the base station position information of networking information stores in the mobile phone terminal memory, antenna gain information, antenna direction information etc. according to base station Base ID.

3. handheld terminal is caught the information of adjacent sectors pilot signal

The handheld terminal processor controls increases reference signal length, adjusts the received signal treated length, catches other two the sector pilot signals information except that the service sector, and demodulation module is determined corresponding pilot offset according to above-mentioned pilot information.Because a little less than the signal of signal than serving sector of all the other two sectors, same base station, therefore need to adopt longer reference signal to increase the signal processing length of terminal, the peak value that makes reference signal and received signal do to produce behind the related operation can be detected.In addition, owing to increased the length of handheld terminal reference signal, might detect the pilot signal of other base stations, therefore the handheld terminal demodulation module carries out demodulation to the information of obtaining from broadcast channel, and the Base ID of the serving sector that contrast obtains guarantees that handheld device catches the pilot signal of same base station.

After capturing a certain pilot signal, continue to obtain the Base id information in its broadcast channel.This Base ID is compared with the Base ID of the serving sector that captures before, if it is identical then think and captured other sector pilot signals under the serving BS, if difference then continue to search for other pilot tones is up to capturing under the serving BS till other two sector pilot signals.Three pilot signals of serving BS are all after the acquisition success, the handheld terminal demodulation module demodulates the pilot offset of other sectors of serving BS in the broadcast channel information, the common signal channel of terminal by system directly obtains or enquiry module is searched list information in the memory, obtains other fan antenna gain table of serving BS and antenna direction information.

4. terminal measurement pilot signals field intensity

According to terminal received signal R (t), with the short code biasing PN of the serving sector of getting out of phase _ACarry out related calculation, get and R (t) when phase place is consistent when phase place, signal produces peak value, obtains the pilot signal strength that handheld device receives according to signal peak.

Pilot signal needed to handle through short code before carrier modulation, and different pilot tones adopts different short code biasings (pilot offset).If the signal R (t) that terminal receives but approximate representation be:

R(t)＝10 ^Fd/2010 ^Gr/2010 ^GA(θ)/20S _P(t-τ)PN _A(t-τ)

+10 ^Fd/2010 ^Gr/2010 ^GB(θ)/20S _P(t-τ)PN _B(t-τ) (1)

+10 ^Fd/2010 ^Gr/2010 ^GG(θ)/20S _P(t-τ)PN _G(t-τ)

+10 ^Fd/2010 ^Gr/20Sother(t-τ)

Wherein parameter τ is a time delay, S _PBe the signal of transmission, each sector of serving BS is identical; PN _A, PN _BAnd PN _GBe respectively the short code that sector A, sector B and sector G adopt with certain biasing; Sother is the stack of other signals of receiving; GA (θ), GB (θ) and GG (θ) are respectively the gains in the θ direction of sector A, sector B and sector G antenna; Because the communication environments basically identical of three road signals, therefore can regard them as has identical space attenuation F _d, the receiving terminal processing gain Gr of three road signals is also identical simultaneously.Actual conditions are the signals for each sector transmission, the signal of incoming terminal all is the set of multipath signal, but because three sector pilot signals are put the wireless channel environment basically identical of terminal center point along base station center, so can use one-channel signal to be equivalent to the multipath signal set.(1) formula show the terminal received signal by three sectors transmit and noise form.

Use the pseudo noise code short code PN of three sectors respectively _A, PN _B, PN _GR (t) obtains its peak signal R (τ as related operation to received signal _A):

$R\left(t\right)\⊕{\mathrm{PN}}_A\left(t_A\right)={10}^{\mathrm{Fd}/20}{10}^{\mathrm{Gr}/20}{10}^{\mathrm{GA}\left(\mathrm{\θ}\right)/20}{S}_P(t-\mathrm{\τ})P{N}_A(t-\mathrm{\τ})\⊕{\mathrm{PN}}_A\left(t_A\right)$

$+{10}^{\mathrm{Fd}/20}{10}^{\mathrm{Gr}/20}{10}^{G\left(\mathrm{\θ}\right)B/20}{S}_P(t-\mathrm{\τ})P{N}_B(t-\mathrm{\τ})\⊕{\mathrm{PN}}_A\left(t_A\right)$

$+{10}^{\mathrm{Fd}/20}{10}^{\mathrm{Gr}/20}{10}^{\mathrm{GG}\left(\mathrm{\θ}\right)/20}{S}_P(t-\mathrm{\τ})\⊕{\mathrm{PN}}_A\left(t_A\right)$

$+{10}^{\mathrm{Fd}/20}{10}^{\mathrm{Gr}/20}\mathrm{Sother}(t-\mathrm{\τ})\⊕{\mathrm{PN}}_A\left(t_A\right)---\left(2\right)$

Because PN _A, PN _BAnd PN _GAll be pseudo random sequence, they have good autocorrelation performance, promptly only in pseudo random sequence when self making related operation generation peak value R (τ _A), and with other sequences (comprising the sequence different) with itself having only phase place when making related operation convergence be 0.Therefore,

$R\left(t\right)\⊕{\mathrm{PN}}_A\left(t_A\right)\≈{10}^{\mathrm{Fd}/20}{10}^{\mathrm{Gr}/20}{10}^{\mathrm{GA}\left(\mathrm{\θ}\right)/20}{S}_P(t-\mathrm{\τ})R\left({\mathrm{\τ}}_A\right)---\left(3\right)$

In like manner, $R\left(t\right)\⊕{\mathrm{PN}}_B\left(t_B\right)\≈{10}^{\mathrm{Fd}/20}{10}^{\mathrm{Gr}/20}{10}^{\mathrm{GB}\left(\mathrm{\θ}\right)/20}\mathrm{SP}(t-\mathrm{\τ})R\left({\mathrm{\τ}}_B\right)---\left(4\right)$

$R\left(t\right)\⊕{\mathrm{PN}}_G\left(t_G\right)\≈{10}^{\mathrm{Fd}/20}{10}^{\mathrm{Gr}/20}{10}^{\mathrm{GG}\left(\mathrm{\θ}\right)/20}\mathrm{SP}(t-\mathrm{\τ})R\left({\mathrm{\τ}}_G\right)---\left(5\right)$

Computing module calls following formula according to peak signal, data processing length and calculates three sector pilot signals intensity that handheld terminal receives, and the intensity expression formula of its pilot signal is:

${\mathrm{SOA}}_{-A}=\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{10}^{\mathrm{Fd}/10}{10}^{\mathrm{Gr}/10}{10}^{\mathrm{GA}\left(\mathrm{\θ}\right)/10}{S}_P^2\left(i\right)R\left({\mathrm{\τ}}_A\right)---\left(6\right)$

${\mathrm{SOA}}_{-B}=\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{10}^{\mathrm{Fd}/10}{10}^{\mathrm{Gr}/10}{10}^{\mathrm{GB}\left(\mathrm{\θ}\right)/10}{S}_P^2\left(i\right)R\left({\mathrm{\τ}}_B\right)---\left(7\right)$

${\mathrm{SOA}}_{-G}=\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{10}^{\mathrm{Fd}/10}{10}^{\mathrm{Gr}/10}{10}^{\mathrm{GG}\left(\mathrm{\θ}\right)/10}{S}_P^2\left(i\right)R\left({\mathrm{\τ}}_G\right)---\left(8\right)$

Wherein parameter N is the data processing length of carrying out related operation when being used to detect.Analysis mode (6) (7) (8) three formulas as can be known, influence receives in each parameter of intensity of pilot signal because R (τ _A), R (τ _B), R (τ _G) approximate identical, except GA (θ), GB (θ) and GG (θ), other each parameter is identical.The reception pilot signal strength described of above three formulas be function about signal propagation direction θ.

5. handheld terminal is set up gain difference and the direction correspondence table that is used for direction finding

The handheld terminal control treatment module is according to above-mentioned the fan antenna gain table and the antenna direction that 3. obtains in the step, make up gain difference and direction corresponding informance table, this table is according to the relation of pilot tone field intensity difference value and two pilot tone field intensity difference values, call its functional relation and determine the aspect angle, be stored in the terminal memory.This information table is triantennary gain difference and antenna direction correspondence table.Be with 120 ° of lobe antennas shown in the table 1, it is example that its level is pointed to three sectors that are respectively 0 °, 120 °, 240 °, the gain difference of structure and direction correspondence table.

Table 1: gain difference and direction correspondence table

SDOA _B_A(dB)	AOA(deg)	SDOA _B_G	AOA(deg)	SDOA _A_G	AOA(deg)
						SDOA _B_G>0 and SDOA _A_G>0		SDOA _B_A>0 and SDOA _A_G<0		SDOA _B_A<0 and SDOA _B_G<0
-26	60	-26	300	-26	-60
						-20	75	-20	285	-20	-45
-17	80	-17	280	-17	-40
						-14	90	-14	270	-14	-30
-10	95	-10	265	-10	-25
						-6	105	-6	255	-6	-15
-2	115	-2	245	-2	-5
						0	0	0	240	0	0
2	125	2	235	2	5
						6	135	6	225	6	15
10	145	10	215	10	25
						14	150	14	210	14	30

17	160	17	200	17	40
						20	165	20	195	20	45
26	180	26	180	26	60
						Other condition		Other condition		Other condition
-26	420	-26	-60	-26	300
						-20	390	-20	-30	-20	270
-17	380	-17	-20	-17	260
						-14	360	-14	0	-14	240
-10	345	-10	15	-10	225
						-6	325	-6	35	-6	205
-2	310	-2	50	-2	190
						0	300	0	60	0	180
2	290	2	70	2	170
						6	275	6	85	6	155
10	255	10	105	10	135
						14	240	14	120	14	120
17	220	17	140	17	100
						20	210	20	150	20	90
26	180	26	180	26	60

6. determine that terminal receives the pilot signal difference value

The three sector pilot signal strength SOA that receive that 4. the handheld terminal computing module is determined according to above-mentioned steps _-A, SOA _-B, SOA _-G, call following formula and calculate pilot tone field intensity difference value: SDOA _{_ B_A}, SDOA _{_ A_G}And SDOA _{_ B_G}With sector A and sector B is example, and establishing pilot transmit power is P ₀, the antenna gain GA (θ) of sector A and sector B, GB (θ) they are the functions that points to angle θ, the space attenuation is F _d, the receiving terminal processing gain is Gr.Receiving terminal pilot frequency intensity SOA _-AAnd SOA _-BExpression formula can be reduced to:

SOA _-A＝P ₀+GA(θ)+G _r-F _d (9)

SOA _-B＝P ₀+GB(θ)+G _r-F _d (10)

SDOA _{_B_A}＝SOA _-B-SOA _-A (11)

In like manner:

SDOA _{_A_G}＝SOA _-A-SOA _-G (12)

SDOA _{_B_G}＝SOA _-B-SOA _-G (13)

7. determine sense

The side direction module is searched the gain difference and the direction correspondence table of storing in the handheld terminal memory according to three field intensity difference values determining and is determined received signal direction (azimuth).Obtain the direction finding value of handheld terminal.

By adopting direction-finding method of the present invention to obtain the azimuth of handheld terminal, can realize the self-align of handheld terminal according to the propagation time of pilot channel estimation terminal to base station simultaneously.All direction findings, position fixing process are all finished in end side, and terminal only need dispose single antenna, do not need additionally to increase the expense of base station and end side, and have effectively prevented the approach of divulging a secret of terminal location.

Above embodiment is that example specifies enforcement of the present invention with the situation of configuration three sectors in the base station only, but the present invention is not limited thereto, in the scope that those skilled in the art can understand, can there be other forms of configuration the base station, also can adopt in the prior art other similar computing formula that relevant parameter is calculated.

Claims (6)

1. handheld terminal direction-finding method that arrives angle AOA based on signal, it is characterized in that, finish signal direction-finding in end side based on single antenna, comprise the steps: that specifically the end message acquisition module catches the base station identity code of serving BS and the pilot offset of each sector, base station, obtain the gain information and the antenna direction information of each fan antenna of serving BS; Control treatment module is utilized antenna gain information and antenna direction information architecture antenna gain difference and direction correspondence table; Computing module calculates the pilot signal strength of its reception according to the pilot offset of terminal received signal, each sector of serving BS, determines the field intensity difference value of pilot signal according to each sector pilot signals intensity; The direction finding module is searched in the memory antenna gain difference and direction correspondence table according to pilot signal field intensity difference value and is determined the direction that signal arrives.

2. handheld terminal direction-finding method according to claim 1 is characterized in that described serving BS adopts three sector configuration, has the directional antenna of 120 ° of deflections, and each fan antenna points to fixing.

3. handheld terminal direction-finding method according to claim 1 is characterized in that, the end message acquisition module obtains the gain information and the antenna direction information of fan antenna by common signal channel.

4. terminal direction-finding method according to claim 1 is characterized in that, the end message acquisition module obtains the gain information and the antenna direction information of fan antenna by the information in the memory.

5. terminal direction-finding method according to claim 1, it is characterized in that, the step that the end message acquisition module is caught each sector pilot offset specifically comprises: acquisition module scans downlink pilot frequency channel and broadcast channel, selects the strongest sector of pilot tone as serving sector; Demodulation module demodulates the pilot offset of serving sector according to the serving sector pilot signal; Increase reference signal length, adjust received signal length and catch other sector pilot signals of serving BS, determine corresponding pilot offset.

6. terminal direction-finding method according to claim 1, it is characterized in that, described pilot signal strength is the function about signal propagation direction θ, the step of calculating pilot signal strength specifically comprises: computing module is according to the terminal received signal, the pilot offset of the serving sector consistent with phase of received signal carries out related calculation, obtain signal peak, determine the pilot signal strength that receives thus.

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