CN114966641B - A spread spectrum distance measurement method based on Sunzi theorem distance deambiguation - Google Patents
A spread spectrum distance measurement method based on Sunzi theorem distance deambiguation Download PDFInfo
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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
- G01S11/00—Systems for determining distance or velocity not using reflection or reradiation
- G01S11/02—Systems for determining distance or velocity not using reflection or reradiation using radio waves
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
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Abstract
The invention discloses a spread spectrum ranging method for resolving ambiguity based on a grandson theorem distance, which comprises the steps of generating three pseudo code sequences at a transmitting end, generating spread spectrum intermediate frequency signals, mixing analog signals of an uplink mixer with the spread spectrum intermediate frequency signals, generating uplink radio frequency signals, sending the uplink radio frequency signals through an antenna, despreading the signals through processing after a satellite receives the uplink radio frequency signals sent by a ground antenna to obtain three pseudo code sequences, comparing the three pseudo code sequences at a receiving end to obtain remainder when the three pseudo codes are measured, calculating the number of chips by using a grandson theorem formula, calculating the total time delay of a microwave round trip space, removing ground zero values and on-satellite zero values, and obtaining the space distance from a ground antenna port to the satellite. The invention can select proper number and length of the pseudo codes according to the distance of the actual distance, and the ranging precision is consistent with the traditional pseudo code ranging precision.
Description
Technical Field
The invention discloses a spread spectrum ranging method for performing distance de-blurring based on a grandson theorem, which can be applied to a frequency-spreading ranging device for performing distance de-blurring based on the grandson theorem, which is integrated with transceiver, is suitable for a satellite system with frequency conversion forwarding, and can perform single-station ranging or multi-station ranging orbit determination on satellites.
Background
In the field of aerospace measurement and control, the traditional distance measurement generally adopts two systems of sounding distance measurement and pseudo code distance measurement, the USB system adopts sounding distance measurement, and utilizes various sounding and sounding mechanisms to perform distance defuzzification, the mechanism has long distance capturing time and low distance measurement precision, and is a more traditional distance measurement method.
Disclosure of Invention
The invention aims to avoid the defects in the background art and provide a spread spectrum ranging method for performing distance defuzzification based on the grandson theorem, which is suitable for a satellite system with frequency conversion forwarding.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
A spread spectrum ranging method for resolving ambiguity based on a grandchild theorem distance comprises the following steps:
(1) Initializing parameters, determining a pseudo code period M 1、m2、m3, calculating a product M of the three, and respectively finding out the number M i divided by M i by the remainder 1 and the other two numbers by integer, wherein i=1, 2 and 3;
(2) Code clock f w with pseudo code and code element width The phase value of the chips less than an integer is PHn;
(3) Generating a pseudo code clock through a pseudo code frequency generator, driving three pseudo code generators to generate pseudo code sequences with three lengths, and sending the pseudo code clock to a carrier frequency generator to generate a local intermediate frequency single carrier signal;
(4) Summing the pseudo codes generated by the three pseudo code generators, carrying out phase modulation on the local intermediate frequency single carrier signal by using a sequence obtained by summation, and converting the modulated signal into a spread spectrum intermediate frequency signal through a digital-to-analog converter;
(5) After receiving an uplink radio frequency signal sent by a ground antenna, a satellite sends the uplink radio frequency signal back to the ground after frequency conversion and forwarding by a satellite frequency converter, and mixes the uplink radio frequency signal with a ground downlink local oscillator to generate a downlink intermediate frequency input signal;
(6) After the downlink intermediate frequency input signal is subjected to intermediate frequency sampling and digital down-conversion, the signal is despread through a capture tracking module to obtain three pseudo code sequences;
(7) Comparing the three pseudo code sequences obtained in the step (6) with the pseudo code sequences generated in the step (3) to obtain a remainder C 1、C2、C3 when the three pseudo codes are measured;
(8) C Total (S) 'is obtained through calculation by using a grandson theorem formula C Total (S) '＝C1*M1+C2*M2+C3*M3, and a remainder C Total (S) of dividing C Total (S) ' by M is calculated;
(9) The total time delay tau Total (S) ＝τw*(C Total (S) +PHn of the microwave round trip space is calculated, the ground zero value tau Ground zero value and the satellite zero value tau On-board zero value are removed, and the space distance from the ground antenna port to the satellite is obtained according to the light speed C:
compared with the background technology, the invention has the following advantages:
1. the invention provides a method for measuring pseudo codes with different pseudo code periods in a system without track forecast or without data frames to perform distance defuzzification, which improves the maximum fuzzification-free distance by respectively measuring the target by two or three pseudo code periods which are prime numbers pseudo codes on the basis of a pseudo code system, and can select a proper pseudo code period to adjust the maximum fuzzification-free distance according to the actual situation.
2. The distance range measured by the traditional pseudo code distance measurement method is related to the pseudo code period length, the measured distance range is far when the pseudo code period is long, the capturing difficulty of a receiving end is improved when the pseudo code period length is long, if the distance is larger than the pseudo code period length, the distance is defuzzified by means of orbit prediction and the like, and the method is based on the solution idea of the grandson theorem, namely the Chinese residual theorem, and the satellite is respectively measured by using pseudo codes with two or three pseudo code periods being prime numbers, so that the residual chip numbers of each pseudo code length when the distance is measured can be respectively obtained, and the total chip number of the pseudo code of the current measured distance can be accurately obtained by using the residual chip numbers.
3. The invention can select proper number and length of the pseudo codes according to the distance of the actual distance, and the ranging precision is consistent with the traditional pseudo code ranging precision. Compared with the traditional ranging, the ranging algorithm is compatible with a hardware platform of a traditional ranging system without changing hardware design, and long-distance ranging can be realized without providing a distance forecast or other auxiliary measures by a system.
Drawings
Fig. 1 is a schematic diagram of an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail below.
A spread spectrum ranging method based on the sun-son theorem distance ambiguity resolution. Pseudo-code ranging obtains a distance value by measuring a phase value PHn of a total chip number C Total (S) + less than the whole chip in the bidirectional space, so that the key of whether the measurement can be successful is to accurately measure C Total (S) , and the total chip number C Total (S) =pseudo-code period length P i ×pseudo-code period number N i + and residual chip number C i. Since the measured distance may be greater than the code length of the current pseudo code period, a plurality of pseudo code periods may be included in the space, and if there is no track forecast or data frame, the number N i of pseudo code periods in the space cannot be obtained, and the method directly obtains C Total (S) by adding pseudo code measurements of different lengths without adding auxiliary measures to the system.
The method utilizes the pseudo codes with two or more pseudo code periods being prime numbers to measure the distance of the satellite, the bidirectional distance value to be measured is a dividend, the pseudo code periods with the prime numbers are equivalent to divisors, corresponding quotient and remainder can be obtained, the grandson theorem shows that the minimum value meeting the requirements of all equations is the bidirectional distance value to be measured, the value is smaller than the product of all divisors, and the actual distance value is accurately measured, so that the no-ambiguity value is larger than the actual measured value, namely the product of all divisors is larger than the maximum measured bidirectional distance value.
The frequency-spread distance measuring device which is integrated with the transceiver and performs distance dissociation and ambiguity based on the grandson theorem respectively performs two-way distance measurement on the target under the scheduling of a program, can respectively obtain the chip remainder C i during each measurement, can directly calculate and obtain the total complete chip total number C Total (S) according to the grandson theorem formula, obtains space delay according to the pseudo code clock rate, and then converts the space delay into a distance value according to the light speed.
The method is particularly suitable for distance measurement or orbit determination service of high-orbit synchronous satellites.
The method can be applied to a frequency-spread distance measuring device which is integrated with the transceiver and is used for carrying out distance dissociation and blurring based on the grandson theorem, and the device comprises the following modules:
The device comprises an AD sampler 1, a carrier frequency generator 2, a short code and carrier capturing and tracking unit 3, a pseudo code frequency generator 4, a pseudo code 1 generator 5, a pseudo code 2 generator 6, a pseudo code 3 generator 7, a grandson theorem de-ambiguity module 8, a distance resolution 9, a pseudo code frequency generator 10, a pseudo code 1 generator 11, a pseudo code 2 generator 12, a pseudo code 3 generator 13, a carrier frequency generator 14 and a DA converter 15.
The workflow of the method is as follows:
Initializing parameters, namely determining a seed pseudo code period M 1、m2、m3 according to the actual selected proper parameters, calculating a product M of the seed pseudo code period M 1、m2、m3, and respectively finding out a number M i divided by M i by 1 and divided by two other numbers;
Taking the pseudo code clock as f w, code element width If the phase value of the chips is PHn, the total time delay tau Total (S) ＝τw*(C Total (S) +PHn of the microwave round trip space is smaller than the integral number;
The local pseudo code frequency generator generates a pseudo code clock, drives the three pseudo code generators to generate pseudo code sequences with three lengths, and simultaneously sends the pseudo code sequences to the carrier frequency generator to generate a local intermediate frequency single carrier signal;
the sequence obtained after the pseudo codes generated by the three pseudo code generators are summed carries out phase modulation on a local intermediate frequency single carrier wave to generate a DA converter to generate a spread spectrum intermediate frequency signal, the analog signal of an uplink mixer mixes with the spread spectrum intermediate frequency signal to generate a radio frequency uplink signal, and the radio frequency uplink signal is sent out through an antenna;
After receiving an uplink radio frequency signal sent by a ground antenna, a satellite sends the uplink radio frequency signal back to the ground for mixing with a ground downlink local oscillator after frequency conversion and forwarding by a satellite frequency converter, and a downlink intermediate frequency input signal is generated;
the down intermediate frequency input signal is subjected to intermediate frequency sampling, digital down conversion and despreading of the signal by a capture tracking module to obtain three pseudo code sequences;
Comparing the three pseudo codes obtained by the receiving end with the pseudo codes of the transmitting end to obtain a remainder C 1、C2、C3 when the three pseudo codes are measured;
Calculating to obtain C Total (S) 'by using a grandson theorem formula C Total (S) '＝C1*M1+C2*M2+C3*M3, wherein C Total (S) is necessarily smaller than the achievement M of the three, subtracting M by using C Total (S) ' until all obtained values are smaller than M, and the obtained values are the obtained C Total (S) ;
after C Total (S) is obtained, the total time delay of the measured microwave round trip space is obtained according to a formula of τ w*(C Total (S) +PHn), the ground zero value τ Ground zero value and the satellite zero value τ On-board zero value are removed, and the space distance from the ground antenna port to the satellite can be obtained according to the light speed C.
The following description will take a practical engineering as an example.
A spread spectrum ranging method for resolving ambiguity based on a grandchild theorem distance comprises the following steps:
Parameter design
Initializing parameters, selecting a pseudo code clock as f w =500 KHz according to the bandwidth condition of a system signal,Each symbol corresponds to a distance of C x τ w =600 meters. Wherein C is the speed of light;
the working principle of distance measurement is to measure the delay between transmitting code and receiving code, because the delay is the delay of the signal reaching the target and returning, the number of code elements
Setting three pseudo code periods M 1、m2、m3 as 79, 83 and 107 respectively according to the grand-son theorem as prime conditions, which are equivalent to divisors in grand-son theorem, and the product M=m 1*m2*m3 = 701559 of the three, which satisfies the condition of being more than 666666 and the final calculation result is necessarily less than M;
Finding out the number M i divided by M i by 1 and divided by the other two, respectively, and calculating M 1＝12*83*107、M2＝51*79*107、M3 = 25 x 79 x 83;
(II) ranging procedure
The flow of the originating device is as follows:
the local pseudo code frequency generator 10 generates a pseudo code clock, drives the pseudo code 1 generator 11, the pseudo code 2 generator 12 and the pseudo code 3 generator 13 to generate pseudo code sequences with three lengths, and simultaneously sends the pseudo code sequences to the carrier frequency generator 14 to generate a local intermediate frequency single carrier signal;
The sequences obtained after the pseudo codes generated by the pseudo code 1 generator 11, the pseudo code 2 generator 12 and the pseudo code 3 generator 13 are summed carry out phase modulation on the intermediate frequency carrier wave generated by the carrier frequency generator 14 to generate a spread spectrum intermediate frequency signal;
The uplink phase lock device of the uplink generates an analog signal of the uplink mixer by using the reference local oscillator clock, the analog signal of the uplink mixer mixes with the spread spectrum intermediate frequency signal output by the DA converter 15, and the generated radio frequency uplink signal is sent out through an antenna.
The receiving device flow:
After receiving an uplink radio frequency signal sent by a ground antenna, a satellite sends the uplink radio frequency signal back to the ground for mixing with a ground downlink local oscillator after frequency conversion and forwarding by a satellite frequency converter, and a downlink intermediate frequency input signal is generated;
The intermediate frequency receiving module AD sampler 1 performs intermediate frequency sampling on a downlink intermediate frequency input signal, and performs digital down-conversion on the downlink intermediate frequency input signal and two paths of orthogonal signals generated by the local carrier frequency generator 2 to obtain I, Q paths of orthogonal spread spectrum signals COS and SIN;
An initial carrier frequency and a pseudocode initial phase are set. Adjusting the time delay of the local oscillator and the pseudo code of the carrier frequency generator 2, and carrying out energy detection on the signal until the energy of the signal exceeds a threshold, wherein the Doppler and the time delay of the signal fall into an initially set capture window, and the spread spectrum signal is despread;
after capturing the signals, the carrier ring and the pseudo code ring are switched into a tracking state, and the carrier and the pseudo code phase are tracked respectively;
(III) distance dissociation calculation
Comparing the three pseudo codes obtained by the receiving end with the pseudo codes of the transmitting end to obtain a remainder C 1、C2、C3 when the three pseudo codes are measured;
Using the grandson theorem formula C Total (S) '＝C1*M1+C2*M2+C3*M3, because C Total (S) must be less than the product M of the three, the final C Total (S) is C Total (S) ' minus M until C Total (S) is less than M;
After obtaining C Total (S) , according to the formula τ w*(C Total (S) +PHn), obtaining the total time delay of the measured space, removing the ground zero value τ Ground zero value and the satellite zero value τ On-board zero value , and according to the light speed C, obtaining the space distance from the ground antenna port to the satellite Wherein τ Ground zero value can be measured by a bias feed loop using the apparatus of the present invention, τ On-board zero value can be provided by the satellite manufacturer;
the calculation of the target distance can be completed through the steps.
In addition to the embodiments described above, other embodiments of the invention are possible. All technical schemes adopting equivalent substitution or equivalent transformation form fall within the protection scope of the invention.
Claims (1)
1. A spread spectrum ranging method for range ambiguity resolution based on a grandson theorem is characterized by comprising the following steps:
(1) Initializing parameters, determining a pseudo code period M 1、m2、m3, calculating a product M of the three, and respectively finding out the number M i divided by M i by the remainder 1 and the other two numbers by integer, wherein i=1, 2 and 3;
(2) Code clock f w with pseudo code and code element width The phase value of the chips less than an integer is PHn;
(3) Generating a pseudo code clock through a pseudo code frequency generator, driving three pseudo code generators to generate pseudo code sequences with three lengths, and sending the pseudo code clock to a carrier frequency generator to generate a local intermediate frequency single carrier signal;
(4) Summing the pseudo codes generated by the three pseudo code generators, carrying out phase modulation on the local intermediate frequency single carrier signal by using a sequence obtained by summation, and converting the modulated signal into a spread spectrum intermediate frequency signal through a digital-to-analog converter;
(5) After receiving an uplink radio frequency signal sent by a ground antenna, a satellite sends the uplink radio frequency signal back to the ground after frequency conversion and forwarding by a satellite frequency converter, and mixes the uplink radio frequency signal with a ground downlink local oscillator to generate a downlink intermediate frequency input signal;
(6) After the downlink intermediate frequency input signal is subjected to intermediate frequency sampling and digital down-conversion, the signal is despread through a capture tracking module to obtain three pseudo code sequences;
(7) Comparing the three pseudo code sequences obtained in the step (6) with the pseudo code sequences generated in the step (3) to obtain a remainder C 1、C2、C3 when the three pseudo codes are measured;
(8) C Total (S) 'is obtained through calculation by using a grandson theorem formula C Total (S) '＝C1*M1+C2*M2+C3*M3, and a remainder C Total (S) of dividing C Total (S) ' by M is calculated;
(9) The total time delay tau Total (S) ＝τw*(C Total (S) +PHn of the microwave round trip space is calculated, the ground zero value tau Ground zero value and the satellite zero value tau On-board zero value are removed, and the space distance from the ground antenna port to the satellite is obtained according to the light speed C:
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| CA2409319A1 (en) * | 2001-11-02 | 2003-05-02 | Spectrum Target Detection Inc. | Spread spectrum radar with leak compensation at baseband |
| CN101241186A (en) * | 2008-03-11 | 2008-08-13 | 陕西长岭电子科技有限责任公司 | Transmitting altimeter based on pseudo-code ranging and pseudo-code method |
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| US6314128B1 (en) * | 1998-07-17 | 2001-11-06 | World Wireless Communications, Inc. | Spread spectrum synchronized receiver and synchronizing methods |
| CN104062646B (en) * | 2014-07-03 | 2016-08-24 | 四川九洲电器集团有限责任公司 | Segmentation correlation unit, pseudo-random code ranging devices and methods therefor |
| CN106842166B (en) * | 2017-03-31 | 2019-04-30 | 东南大学 | A Velocity Ambiguity Solution Applicable to Chirp Continuous Wave Radar System |
| CN108845338B (en) * | 2018-07-26 | 2022-04-01 | 西南电子技术研究所（中国电子科技集团公司第十研究所） | Satellite-ground combined carrier smoothing pseudorange ranging method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CA2409319A1 (en) * | 2001-11-02 | 2003-05-02 | Spectrum Target Detection Inc. | Spread spectrum radar with leak compensation at baseband |
| CN101241186A (en) * | 2008-03-11 | 2008-08-13 | 陕西长岭电子科技有限责任公司 | Transmitting altimeter based on pseudo-code ranging and pseudo-code method |
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