CN104181501A - Positioning system and positioning method based on ground digital radio and television signals - Google Patents
Positioning system and positioning method based on ground digital radio and television signals Download PDFInfo
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- CN104181501A CN104181501A CN201410414944.3A CN201410414944A CN104181501A CN 104181501 A CN104181501 A CN 104181501A CN 201410414944 A CN201410414944 A CN 201410414944A CN 104181501 A CN104181501 A CN 104181501A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
- G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
- G01S5/10—Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements, e.g. omega or decca systems
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Abstract
A positioning system based on ground digital radio and television signals comprises a down-conversion and sampling device, a fractional delay TDOA detection device, a receiver position calculation device and a signal-noise ratio estimating device. A positioning method includes the steps that (1) discrete signals are obtained through sampling, (2) related processing is carried out, (3) arrival time difference of signals of integral multiple sampling periods and fractional arrival time difference of different ground digital television emitter signals arriving at a positioning receiver are detected, (4) a total time delay differential is obtained through combination, (5) the total time delay differential is converted to distance, and coordinates of the receiver are obtained through the geometrical relation of the coordinates. By means of the system and the method, on the premise that good performance of integral multiple sampling period delay and low complexity of a system are guaranteed, small multiple sampling period delay can be accurately obtained, error limitations of a sampling period are broken through, precision of the system is improved again, and error estimation and precision compensation are carried out on results of a positioning system in advance through environment detection.
Description
Technical field:
What the present invention relates to is that a kind of use ground digital television broadcast signal carries out high precision poor extraction time of arrival, and utilizes the arrival mistiming to carry out the method for hi-Fix, belongs to wireless communication technology field.
Background technology:
Time of arrival, poor location technology (TDOA, Time Difference of Arrival), was a kind of wireless location technology.Be different from the technology of using absolute time location, TDOA technology is the mistiming arriving by detecting the signal of two transmitting base stations, rather than the absolute time arriving determines the position of mobile reception platform, has reduced time synchronized requirement.
TDOA location technology is as a research direction of wireless location technology, its technical characteristics is: TDOA technology detected by the mistiming, when calculating TDOA value, the error of calculation to all base stations, be all identical and itself and be zero, these errors comprise public multipath error and clock synchronous error.
TDOA location technology based on ground digital television broadcast, is that by broad sense simple crosscorrelation, to extract time of arrival of Different Ground digital TV transmitter signal poor, thereby determines the position of location receiver.Because the precision of TDOA location technology directly depends on the precision that records the mistiming, therefore the precision overwhelming majority of the TDOA location technology based on ground digital television broadcast depends on the precision of the mistiming of extracting by broad sense simple crosscorrelation.But the mistiming of extracting due to broad sense simple crosscorrelation is to postpone in the sampling period that shows integral multiple, therefore for discrete digital signal, broad sense simple crosscorrelation poor technology of extraction time only can obtain the delay in integral multiple sampling period accurately, and shows that the decimal times time delay on signal phase can not detect easy and accurately.This extraction time, poor error limitation caused the TDOA location technology based on ground digital television broadcast cannot reach very high precision.
Summary of the invention:
The problem existing for prior art, the object of the invention is to propose a kind of localization method and positioning system based on ground digital television broadcast signal, can accurately detect decimal sampling cycle delay but exceed raising system complexity, make to receive function and obtain fast, simply, accurately time delay, thereby improve the precision of location.
Main idea of the present invention is: ground digital television broadcast signal is actual in the process of propagating is the delay that has the decimal sampling cycle, but because the relevant method of the time domain based on traditional is difficult to detect, so limited the precision of the TDOA location technology based on ground digital television broadcast.The present invention uses FIR wave filter the decimal be difficult for detecting doubly to be postponed to change into signal after the processing of easy detection, makes system exceeding the delay that detect comparatively accurately signal increase system complexity in the situation that.In addition the correlation peak due to signal postpones the nonlinear characteristic having in time, using linear FIR wave filter not detect accurately decimal doubly postpones, in order to obtain more accurate result the low computation complexity in the situation that, can be by the delay drop point of signal in comparatively linear region in the delay that location receiver is additional certain, just can not only accurately but also simply obtain the time delay that signal is propagated, thus location receiver position fast and accurately.
The object of the invention is to rely on following technical scheme to realize:
A kind of high-accuracy position system based on ground digital television broadcast signal, its feature is, comprising: down coversion and sampling apparatus, minute several times time delay TDOA pick-up unit based on relevant, with receiver location calculation element and the SNR estimation device of data processing function;
Described down coversion and sampling apparatus by radio frequency, transfer the ground digital television broadcast signal receiving to intermediate frequency and sampling obtains after discrete signal, is transferred to described minute several times time delay TDOA pick-up unit and SNR estimation device based on relevant;
The PN sequence of described signal based on several times time delay TDOA pick-up unit received in relevant minute and known formation frame head is carried out simple crosscorrelation, and detect respectively integral multiple time delay and minute several times time delay, and after a minute several times time delay is calibrated, two parts time delay is merged, will obtain the poor receiver location calculation element that is transferred to of time delay;
Described SNR estimation device, by the signal to noise ratio (S/N ratio) receiving is estimated, adjusts filter parameter adaptively, and the offset calculating is transferred to receiver location calculation element;
Described receiver location calculation element utilizes each mistiming of TDOA algorithm process and position coordinates is exported, according to the detected tv signal-noise ratio SNR of SNR estimation device, come adaptively the poor deviation of time delay to be compensated to correction, improve accuracy of detection simultaneously.
A described minute several times time delay TDOA pick-up unit based on relevant comprises: detecting device, half integer multiple time delay estimator and TDOA time delay combiner when correlator, integral multiple time delay detection device, minute several times;
Described correlator, carries out relevant by the ground digital television broadcast signal receiving to the PN sequence of known formation frame head;
Described integral multiple time delay detection device, carries out Detection and Extraction integral multiple time delay to correlated results;
Detecting device during described minute several times, carries out Detection and Extraction minute several times time delay to correlated results, and minute several times time delay based on PN Serial relation is transformed to linear signal;
Described half integer multiple time delay estimator, for improving the estimated accuracy when minute several times time delay is less than 0.5 symbol;
Described TDOA time delay combiner, differs from integral multiple symbol delay mistiming and minute several times symbol delay time to add up to and calculates the total time delay difference of signal.
A high-precision locating method that utilizes the described high-accuracy position system based on ground digital television broadcast signal to carry out, is characterized in that, the method comprises the steps:
1. by radio frequency, transfer reception ground digital television broadcast signal to intermediate frequency and sampling obtains discrete signal;
2. the PN sequence of discrete signal and local known formation frame head is carried out to relevant treatment, obtain their cross correlation results;
3. utilize auto-correlation and the their cross correlation of PN sequence, detect the signal arrival time difference in integral multiple sampling period, it is poor time of arrival that the fractional time delay filter of utilization minute several times time delay detection device detects minute several times of Different Ground digital TV transmitter signal arrival location receiver;
4. integral multiple symbol delay mistiming and minute several times symbol delay mistiming are merged and obtain the total time delay difference of signal;
5. time delay difference is scaled apart from and obtains by the geometric relationship of coordinate the coordinate setting of receiver.
System of the present invention is used the method for up-sampling to improve the sampling rate of signal, location receiver to the PN sequence with known formation frame head, the signal receiving has had time delay in the process of propagating, by sampling rate being brought up to certain frequency, necessarily on depth, improve institute's energy detected time of arrival of difference precision, the method that still improves simply sampling rate will increase the complexity of hardware greatly.
Use minute several times filtering wave by prolonging time device to be converted into by being not easy minute several times time delay based on PN sequence phase that direct estimation goes out the linear signal easily obtaining.This wave filter can adopt the FIR wave filter of fixed coefficient to realize, so its complexity is very simple.
When minute several times time delay estimating is less than 0.5, nonlinear minute several times time delay detection result become and be close to linear result, thereby nonlinear test problems is converted into linear test problems, has reduced the complexity of time delay detection and estimation, and improved the precision of location algorithm.
By the signal to noise ratio (S/N ratio) estimating, adaptively detected result is carried out to estimation of error and accuracy compensation.
A kind of high-precision locating method based on ground digital television broadcast signal of the present invention is compared with traditional TDOA localization method based on ground digital television broadcast, guaranteeing under the characteristic of superperformance that the integral multiple sampling period postpones and the low complex degree of system, thereby using FIR wave filter to detect can to obtain exactly the error limitation in a decimal sampling cycle delay sampling period of breakthrough promotes the precision of system again; Use half time delay detecting method to compensate original detection method, can be so that the detection that decimal doubly postpones becomes linear, more simply accurately; Use the method that receives signal up-sampling under the precondition of speed that does not change signal transmission, to reduce exponentially the orientation distance error estimating; The signal to noise ratio (S/N ratio) that use estimates is carried out the method for adaptively correcting to detection error, can be by the detection of environment in advance the result of positioning system is carried out to estimation of error and accuracy compensation.
Accompanying drawing explanation:
Fig. 1 TDOA principle schematic of the present invention.
Fig. 2 system chart of the present invention.
Minute several times time delay TDOA of Fig. 3 based on relevant detects.
Fig. 4 the present invention divides several times time delay detection wave filter time domain shock response schematic diagram.
The frame structure schematic diagram of the digital television ground broadcast signal that Fig. 5 the present invention adopts.
Embodiment:
Below in conjunction with the drawings and specific embodiments, the present invention will be further described.The present embodiment is implemented take technical solution of the present invention under prerequisite, provided detailed embodiment and concrete operating process, but protection scope of the present invention is not limited to following content.
Fig. 1 is TDOA principle schematic of the present invention, and as shown in Figure 1, TDOA location is a kind of method that the mistiming positions of utilizing.Due to generally more difficult measurement of absolute time, therefore by the TV signal that relatively Different Ground digital TV transmitter is launched, arrive the mistiming of location receiver, just can make and take signal source as focus, the hyperbolic curve that range difference is major axis, hyp intersection point is exactly the position of receiver.In TDOA algorithm, positioning precision relies on time difference information to decide, so the method that the present invention utilizes ground digital television broadcast signal to provide high-precision time difference information to draw high-precision range information reaches high-precision positioning result.
At location receiver, use the method for up-sampling, for improving the sampling rate of signal, to shorten the sampling period; Use fractional time delay filter to estimate the time of arrival in fraction time sampling cycle from receive signal poor, the method can be in order to the distance between accurate Calculation terrestrial DTV transmitter and location receiver; Use the time delay of half integer multiple sampling period to estimate, improve the estimated accuracy when minute several times time delay is less than 0.5; Can also to detection error, compensate correction adaptively according to the signal to noise ratio (S/N ratio) of input signal, to improve accuracy of detection.
The frame head of ground digital television broadcast signal consists of PN sequence, and frame originating point information does not change with the data that send; The signal receiving is carried out relevant to the PN sequence of known formation frame head, and utilize auto-correlation and the their cross correlation of PN sequence, by detecting the relative position of the peak value of relevant peaks, the time of arrival that just can estimate the TV signal arrival location receiver that different terrestrial DTV transmitters launches is poor.Utilize method that PN is relevant can detect the signal arrival time difference in integral multiple sampling period, and utilize fractional time delay filter can detect Different Ground digital TV transmitter signal, to arrive minute several times of location receiver poor time of arrival, thereby obtain more accurate range information.
Because noise can bring negative impact to poor estimated accuracy time of arrival, by the signal to noise ratio (S/N ratio) receiving is estimated, then adjust filter parameter adaptively, can compensate estimated result, further to improve the precision of estimation.
System architecture of the present invention as shown in Figure 2, according to the location receiver based on ground digital television broadcast signal of a kind of example of the present invention, comprise down coversion and sampling apparatus, minute several times time delay TDOA pick-up unit based on relevant, with receiver location calculation element and the SNR estimation device of data processing function.
Location receiver receives directly through the ground digital television broadcast signal of channel, transfers the ground digital television broadcast signal receiving to intermediate frequency and sampling obtains discrete signal and sends into minute several times time delay TDOA pick-up unit and the SNR estimation device based on being correlated with in down coversion and sampling apparatus by radio frequency.As shown in Figure 3, in minute several times time delay TDOA pick-up unit based on relevant, there is independently module to be correlated with and separated TV signal respectively, and detect and merge the time delay of TV signal.According to this testing result, receiver location calculation element is by each mistiming of use TDOA algorithm process and obtain position output, and according to SNR estimation device, detected tv signal-noise ratio SNR comes adaptively detection error to be compensated to correction, to improve accuracy of detection.
The high-precision locating method that a kind of high-accuracy position system based on ground digital television broadcast signal is carried out comprises the steps:
1. by radio frequency, transfer reception ground digital television broadcast signal to intermediate frequency and sampling obtains discrete signal;
2. the PN sequence of discrete signal and local known formation frame head is carried out to relevant treatment, obtain their cross correlation results;
3. utilize auto-correlation and the their cross correlation of PN sequence, detect the signal arrival time difference in integral multiple sampling period, it is poor time of arrival that the fractional time delay filter of utilization minute several times time delay detection device detects minute several times of Different Ground digital TV transmitter signal arrival location receiver;
4. integral multiple symbol delay mistiming and minute several times symbol delay mistiming are merged and obtain the total time delay difference of signal;
5. time delay difference is scaled apart from and obtains by the geometric relationship of coordinate the coordinate setting of receiver.
As shown in Figure 5, itself just has the frame head consisting of PN sequence the frame structure of ground digital television broadcast signal, the data that this frame head is not sent change and change, and when extracting time information, only need to use this changeless frame head sequence, therefore do not need to change transmitter and the signal format of ground digital television broadcast signal.
In the process that signal is propagated in channel, had time delay, such time delay can be embodied on signal and can extract by auto-correlation.Because the frame head of ground digital television broadcast signal is to consist of the PN sequence of presetting, therefore can the signal receiving be sent into correlator with the PN sequence of the known formation frame head of this locality at receiver simultaneously carry out relevant treatment, just can obtain their cross correlation results, and due to the autocorrelation performance of PN sequence own, the acknowledge(ment) signal that comprises PN sequence can produce correlation peak because of its common PN sequence with the PN sequence of sending into correlator, because time delay can postpone the PN sequence generation in signal, the correlation peak obtaining so also can produce displacement and distortion, this has reflected the propagation delay of signal.The relevant treatment of the signal that receiver process is sent the transmitter of the different coordinates in office just can obtain the propagation delay that signal arrives different receivers, due to the definitely difficult detection of time delay, therefore make all transmitters keep clock synchronous just can obtain the propagation time delay difference that unlike signal arrives receiver, by time delay difference be scaled apart from and geometric relationship by the coordinate coordinate that just can obtain receiver complete location.Time delay difference consists of with the signal arrival time difference in the fraction time sampling cycle that can not directly read the signal arrival time difference in the integral multiple sampling period that can directly read.
Because correlated results is not easy directly to detect, therefore correlated results can be sent into fractional time delay filter, as shown in Figure 4, by detecting device signal afterwards after filtering, just can obtain more accurate range information.
Because the correlation peak of ground digital television broadcast signal postpones the nonlinear characteristic having in time, use linear fractional time delay filter can not extract accurate decimal and doubly postpone.Therefore as shown in Figure 3, system increased a half-integer time delay estimation module before detection obtains range information, by the time delay of artificial increase half integer multiple, only get between strong linear decimal times delay zone as between detection zone, by times deferred constraint of all decimals in the stronger part of linearity, just can obtain minute several times time delay more accurately, finally more detected integral multiple time delay and a minute several times time delay be merged.
Because noise can bring negative impact to poor estimated accuracy time of arrival, therefore after system obtains range information, need to estimate by signal to noise ratio (S/N ratio) (SNR) to the received signal, according to signal to noise ratio (S/N ratio), adjust adaptively wave filter output gain again, so that estimated result is compensated, and further improve the precision of estimating.
Claims (3)
1. the high-accuracy position system based on ground digital television broadcast signal, it is characterized in that, comprising: down coversion and sampling apparatus (1), minute several times time delay TDOA pick-up unit (2) based on relevant, with receiver location calculation element (3) and the SNR estimation device (4) of data processing function;
Described down coversion and sampling apparatus (1) by radio frequency, transfer the ground digital television broadcast signal receiving to intermediate frequency and sampling obtains after discrete signal, is transferred to described minute several times time delay TDOA pick-up unit (2) based on relevant and SNR estimation device (3);
The PN sequence of described signal based on several times time delay TDOA pick-up unit (2) received in relevant minute and known formation frame head is carried out simple crosscorrelation, and detect respectively integral multiple time delay and minute several times time delay, and after a minute several times time delay is calibrated, two parts time delay is merged, will obtain the poor receiver location calculation element (3) that is transferred to of time delay;
Described SNR estimation device (4), by the signal to noise ratio (S/N ratio) receiving is estimated, adjusts filter parameter adaptively, and the offset calculating is transferred to receiver location calculation element (3);
Described receiver location calculation element (3) utilizes each mistiming of TDOA algorithm process and position coordinates is exported, according to the detected tv signal-noise ratio SNR of SNR estimation device, come adaptively the poor deviation of time delay to be compensated to correction, improve accuracy of detection simultaneously.
2. the high-accuracy position system based on ground digital television broadcast signal according to claim 1, it is characterized in that, a described minute several times time delay TDOA pick-up unit (2) based on relevant comprising: detecting device (23), half integer multiple time delay estimator (24) and TDOA time delay combiner (25) when correlator (21), integral multiple time delay detection device (22), minute several times;
Described correlator (21), carries out relevant by the ground digital television broadcast signal receiving to the PN sequence of known formation frame head;
Described integral multiple time delay detection device (22), carries out Detection and Extraction integral multiple time delay to correlated results;
Detecting device (23) during described minute several times, carries out Detection and Extraction minute several times time delay to correlated results, and minute several times time delay based on PN Serial relation is transformed to linear signal;
Described half integer multiple time delay estimator (24), for improving the estimated accuracy when minute several times time delay is less than 0.5 symbol;
Described TDOA time delay combiner (25), differs from integral multiple symbol delay mistiming and minute several times symbol delay time to add up to and calculates the total time delay difference of signal.
3. a high-precision locating method that utilizes the high-accuracy position system based on ground digital television broadcast signal described in claim 1 or 2 to carry out, is characterized in that, the method comprises the steps:
1. by radio frequency, transfer reception ground digital television broadcast signal to intermediate frequency and sampling obtains discrete signal;
2. the PN sequence of discrete signal and local known formation frame head is carried out to relevant treatment, obtain their cross correlation results;
3. utilize auto-correlation and the their cross correlation of PN sequence, detect the signal arrival time difference in integral multiple sampling period, it is poor time of arrival that the fractional time delay filter of utilization minute several times time delay detection device detects minute several times of Different Ground digital TV transmitter signal arrival location receiver;
4. integral multiple symbol delay mistiming and minute several times symbol delay mistiming are merged and obtain the total time delay difference of signal;
5. time delay difference is scaled apart from and obtains by the geometric relationship of coordinate the coordinate setting of receiver.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105403858A (en) * | 2015-10-28 | 2016-03-16 | 上海电机学院 | Arrival time difference estimation method |
| CN109819516A (en) * | 2019-03-13 | 2019-05-28 | 北京航空航天大学 | A kind of television broadcasting signal forwarding localization method and device |
| CN110261819A (en) * | 2019-06-19 | 2019-09-20 | 南京航空航天大学 | Multiple no-manned plane co-located method based on delay compensation |
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| CN113702901B (en) * | 2021-09-02 | 2024-06-11 | 南京航空航天大学 | Cross-correlation time delay estimation method based on signal correlation enhancement |
| CN114442034A (en) * | 2022-02-10 | 2022-05-06 | 广东行远机器人技术有限公司 | Positioning method and device based on hyperbolic TDOA and computer readable storage medium |
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