Estimation system and method for aviation GPS signal delay
阅读说明：本技术 一种用于航空gps信号延迟的估算系统及其方法 (Estimation system and method for aviation GPS signal delay ) 是由 丛超 杨良勇 孙闻 邴志光 曾杰 王飞 肖振飞 于 2019-10-23 设计创作，主要内容包括：本发明公开了一种用于航空GPS信号延迟的估算系统,同时公开了航空GPS信号延迟的估算方法,是针对GPS信号定位的时间延迟提出了一种估算方法,通过比较GPS更新时间和导航服务器更新时间,选择延迟估算时间相对接近的一种,并且增加一个时间延迟的估计值△test,最大限度的减少未知延迟时间的影响,且将误差最大值限定在△test范围内；采用本技术方案,得出的估算值能最大限度的靠近真实值,并且可以将延迟误差限定在一定范围内,实施起来也较为方便。(The invention discloses an estimation system for aviation GPS signal delay, and simultaneously discloses an estimation method for aviation GPS signal delay, which provides an estimation method for time delay of GPS signal positioning, selects one of delay estimation time which is relatively close by comparing GPS update time with navigation server update time, and adds an estimated value △ test of time delay to reduce the influence of unknown delay time to the maximum extent, and limits the maximum value of error to the range of △ test.)
1. An estimation system for airborne GPS signal delay, characterized by: the GPS signal receiver comprises a signal receiver (C101) used for receiving GPS signals and an aviation computing resource partition (C102) in communication connection with the signal receiver, wherein the aviation computing resource partition (C102) comprises a GPS server (C103) and a navigation server (C104), the GPS server (C103) and the navigation server (C104) are in communication connection through a signal interface, and the GPS server (C103) receives the GPS signals through the signal receiver (C101) and outputs the GPS signals to the navigation server (C104).
2. An estimation system for aviation GPS signal delay as claimed in claim 1, wherein said signal receiver (C101) is connected with GPS server in communication to receive GPS position signal input by the signal receiver (C101) and convert it into communication signal to be transmitted to the GPS server, the GPS server processes and distributes the received GPS signal to the communication interface connected with the navigation server (C104), and the navigation server (C104) acquires data through the communication interface and uses it.
3. An estimation method for an airborne GPS signal delay, comprising an estimation system for an airborne GPS signal delay according to any of claims 1 to 2, comprising the steps of:
s1, comparing the GPS updating time with the navigation server updating time, and selecting one of the delay estimation time which is relatively close to the delay estimation time;
s2, adding an estimated value △ test of time delay, reducing the influence of unknown delay time to the maximum extent, and limiting the maximum value of the error within the △ test range;
and S3, obtaining an optimal time delay estimation strategy.
4. An estimation method for aviation GPS signal delay as claimed in claim 3, wherein said step S1 includes the GPS time (△ t) elapsed between GPS updatesGPSB102) Elapsed message reception interval between navigation server updates (△ t)NavB112) Unknown time delay at first update (△ t)0B110) The unknown time delay during this update period (△ t)nB104) Time when the GPS server issues an interface to the navigation server for use at the first update (△ t)acr,0B111) The nth time this update was issued by the GPS server to the time of interface to navigation server usage (△ t)acr,nB105) Actual time of calculation (T) of first GPS fix0B101) Actual time of calculation (T) of nth GPS fixnB103) The actual time of use (T) of the navigation server receiving the nth GPS positioningn+1B106) (ii) a The estimation equation is as follows:
estimating the actual reception time of the nth GPS fix without including an unknown time delay:
TNav,n＝T0+△tNav+△tacr,0estimating by navigation server time
TGPS,n＝T0+△tGPS+△tacr,n＝Tn+△tacr,nEstimation according to GPS time
Actual time delay:
Tn+1-Tn
estimated time delay, not including unknown time delay:
TNav,n-Tn
error in estimated time:
Tn+1-TNav,n＝△t0estimating by navigation server time
Tn+1-TGPS,n＝△tnEstimation according to GPS time
Difference in estimated time due to elapsed time
TGPS,n-TNav,n＝△t0-△tn
If T isGPS,n-TNav,n>0, i.e. △ t0>△tnThen the error estimated as GPS time is smaller and the unknown time delay updated is smaller, therefore, TGPSAnd TNavIn contrast, TGPSThe estimation of the actual time is more accurate, and the time of the navigation server is expressed by TGPS,nSynchronizing;
on the contrary, if TGPS,n-TNav,n<0, then the error in GPS time estimation is larger because △ t0<△ tn, therefore, the time representation T of the navigation serverNav,nIs a more accurate estimate of the actual time.
5. An estimation method for the aviation GPS signal delay according to claim 3, wherein the scientific error in the estimated time in the step S2 is that the influence of the unknown time delay is further reduced by adding an estimated value △ test of the time delay to divide the time delay into two parts and estimating △ test by observation test, and the specific analysis is as follows:
suppose △ tu,0The portion of the unknown component of the total unknown time delay that is not covered by △ test, then
△t0＝△test+△tu,0Unknown time delay of first update
△tn＝△test+△tu,nUnknown time delay of nth update
Applying the estimated time delay to the GPS updated actual time estimate and its corresponding error to obtain an actual receive time estimate for the nth GPS fix:
TNav,n＝T0+ΔtNav+Δtacr,0+Δtestestimating by navigation server time
TGPS,n＝T0+ΔtGPS+Δtacr,n+ΔtestEstimation according to GPS time
Estimating a time error:
Tn+1-TNav,n＝Δtu,0estimating by navigation server time
Tn+1-TGPS,n＝Δtu,nEstimation according to GPS time
Estimated time difference due to elapsed time:
TGPS,n-TNav,n＝Δtu,0-Δtu,n
if the estimate △ test is close to the actual time delay △ t0&△tnThe error can be significantly reduced and the size of the error is limited to △ test.
Because of Δ tn>＝0&Δtn＝Δtest+Δtu,n,
If Δ tu,n<0,
|Δtu,n|＝<Δtest。
6. An estimation method for airborne GPS signal delay according to claim 3, characterized in that the recorded data of the flight data is collected a plurality of times, the actual deviation values of the deviation values between the attitude heading reference system ADAHR of the atmospheric data and the turns of the GPS track in the flight data are compared, the average value of the deviation values is found, and the optimum △ test value suitable for the aircraft is found in combination with the update cycle of the GPS.
Technical Field
The invention belongs to the field of aviation flight, and particularly relates to a system and a method for estimating GPS signal delay in an aviation flight process.
Background
Time-synchronized delay estimation of GPS signals is crucial to achieving a solution for aircraft position and velocity. The asynchronous motion due to the time delay has a large influence on the guidance control.
In the existing research on GPS positioning delay, a mirror combination capable of reflecting sunlight vertically is arranged on a ground reference point with known coordinates in foreign countries, and when an airplane flies over the mirror combination at a certain speed, a circuit device of the airplane can detect a light beam and record time. Comparing the time of flight GPS output location with the reference point location can result in a positioning offset due to post positioning. The study does not directly calculate the positioning lag time, and the measured data is used for deducing the lag time. However, the method requires that the GPS has high positioning accuracy, and is difficult to implement and difficult to popularize and apply. Still another scholars propose to establish a nonlinear system state equation by the positioning lag time, the positioning output of the autonomous positioning instrument and the positioning output of the GPS, and to perform calculation by the extended kalman filter. The assumption that this equation of state holds is that the lag time is considered to be a fixed, constant quantity. Therefore, the method is only suitable for the situation that the lag time fluctuation is not large, and the motion error such as speed change is large. The method has great limitations, is difficult to popularize and apply, and is particularly not suitable for flying motion.
Disclosure of Invention
The invention aims to solve the technical problem of providing an estimation system and method for GPS signal delay in the aviation flight process.
In order to achieve the purpose, the invention adopts the technical scheme that: an estimation system for aviation GPS signal delay comprises a signal receiver (C101) for GPS signal reception and an aviation computing resource partition (C102) in communication connection with the signal receiver, wherein the aviation computing resource partition (C102) comprises a GPS server (C103) and a navigation server (C104), the GPS server (C103) and the navigation server (C104) are in communication connection through a signal interface, and the GPS server (C103) receives GPS signals through the signal receiver (C101) and outputs the GPS signals to the navigation server (C104).
The invention discloses an estimation system for aviation GPS signal delay, wherein a signal receiver (C101) is in communication connection with a GPS server to receive a GPS position signal input by the signal receiver (C101) and convert the GPS position signal into a communication signal to be transmitted to the GPS server, the GPS server processes and distributes the received GPS signal to a communication interface connected with a navigation server (C104), and the navigation server (C104) acquires data through the communication interface and uses the data
The invention discloses an estimation method for aviation GPS signal delay, which comprises the following steps:
s1, comparing the GPS updating time with the navigation server updating time, and selecting one of the delay estimation time which is relatively close to the delay estimation time;
s2, adding an estimated value △ test of time delay, reducing the influence of unknown delay time to the maximum extent, and limiting the maximum value of the error within the △ test range;
and S3, obtaining an optimal time delay estimation strategy.
The invention discloses an estimation method for aviation GPS signal delay, wherein the step S1 comprises the GPS time (△ t) passing between GPS updatesGPSB102) Elapsed message reception interval between navigation server updates (△ t)NavB112) Unknown time delay at first update (△ t)0B110) The unknown time delay during this update period (△ t)nB104) Time when the GPS server issues an interface to the navigation server for use at the first update (△ t)acr,0B111) The nth time this update was issued by the GPS server to the time of interface to navigation server usage (△ t)acr,nB105) Actual time of calculation (T) of first GPS fix0B101) Actual time of calculation (T) of nth GPS fixnB103) Navigation systemThe server receives the actual time of use (T) of the nth GPS positioningn+1B106) (ii) a The estimation equation is as follows:
estimating the actual reception time of the nth GPS fix without including an unknown time delay:
TNav,n＝T0+△tNav+△tacr,0estimating by navigation server time
TGPS,n＝T0+△tGPS+△tacr,n＝Tn+△tacr,nEstimation according to GPS time
Actual time delay:
Tn+1-Tn
estimated time delay, not including unknown time delay:
TNav,n-Tn
error in estimated time:
Tn+1-TNav,n＝△t0estimating by navigation server time
Tn+1-TGPS,n＝△tnEstimation according to GPS time
Difference in estimated time due to elapsed time
TGPS,n-TNav,n＝△t0-△tn
If T isGPS,n-TNav,n>0, i.e. △ t0>△tnThen the error estimated as GPS time is smaller and the unknown time delay updated is smaller, therefore, TGPSAnd TNavIn contrast, TGPSThe estimation of the actual time is more accurate, and the time of the navigation server is expressed by TGPS,nSynchronizing;
on the contrary, if TGPS,n-TNav,n<0, then the error in GPS time estimation is larger because △ t0<△ tn, therefore, the time representation T of the navigation serverNav,nIs a more accurate estimate of the actual time.
The invention discloses an estimation method for aviation GPS signal delay, wherein scientific errors exist in the estimation time in the step S2, an estimation value △ test of time delay is added, unknown time delay is divided into two parts, an observation test is used for measuring and calculating △ test, and the influence of the delay can be further reduced, and the specific analysis is as follows:
suppose △ tu,0The portion of the unknown component of the total unknown time delay that is not covered by △ test, then
△t0＝△test+△tu,0Unknown time delay of first update
△tn＝△test+△tu,nUnknown time delay of nth update
Applying the estimated time delay to the GPS updated actual time estimate and its corresponding error to obtain an actual receive time estimate for the nth GPS fix:
TNav,n＝T0+ΔtNav+Δtacr,0+Δtestestimating by navigation server time
TGPS,n＝T0+ΔtGPS+Δtacr,n+ΔtestEstimation according to GPS time
Estimating a time error:
Tn+1-TNav,n＝Δtu,0estimating by navigation server time
Tn+1-TGPS,n＝Δtu,nEstimation according to GPS time
Estimated time difference due to elapsed time:
TGPS,n-TNav,n＝Δtu,0-Δtu,n
if the estimate △ test is close to the actual time delay △ t0&△tnThe error can be significantly reduced and the size of the error is limited to △ test.
Because of Δ tn>＝0&Δtn＝Δtest+Δtu,n,
If Δ tu,n<0,
|Δtu,n|＝<Δtest。
The invention discloses an estimation method for aviation GPS signal delay, which is characterized in that recorded data of flight data for multiple times are collected, actual asynchronous deviation values between an atmospheric data attitude heading reference system (ADAHR) and a turn of a GPS track in the flight data are compared, the average value of the deviation values is calculated, and the optimal △ test value suitable for the aircraft is obtained by combining the update cycle of a GPS.
By adopting the technical scheme, the passing time between the GPS time stamps is compared with the passing time between the GPS messages used by the navigation server through an algorithm so as to reduce unknown components and reduce the error, T, of the estimation of the GPS timeGPSAnd TNavIn contrast, TGPSThe estimation of the actual time is more accurate, and the time of the navigation server is expressed by TGPS,nBecause the estimated value △ test is added in the algorithm, the influence of unknown delay time is reduced to the maximum extent, and the error value is limited in the estimated value, the estimated GPS signal delay is more accurate, and has a greater auxiliary effect on GPS signal positioning in flight dynamic.
The invention will be explained in more detail below with reference to the drawings and examples.
Drawings
The contents of the description and the references in the drawings are briefly described as follows:
FIG. 1 is a prior art non-synchronized GPS update diagram of the present invention;
FIG. 2 is a flow chart of the present invention for GPS signal reception;
FIG. 3 is a diagram illustrating the delay between GPS updates according to the present invention.
Marked in the figure as C101, a signal receiver, C102, an aviation computing resource partition, C103, a GPS server, C104, a navigation server and △ tGPSB102 GPS time elapsed between GPS updates △ tNavB112 message reception interval elapsed between navigation server updates △ t0B110 unknown time delay in first update △ tnB104 unknown time delay of nth update period △ tacr,0B111: for the first timeTime when GPS server releases interface to navigation server use △ tacr,nB105: the nth time when the GPS server is used by the interface to the navigation server during the updating; t is0B101: actual calculation time of the first GPS fix; t isnB103: actual calculation time of the nth GPS positioning; t isn+1B106: the navigation server receives the actual time of use of the nth GPS fix.
Detailed Description
The following description of the embodiments of the present invention, with reference to the accompanying drawings, will be made in further detail for the purpose of providing a more complete, accurate and thorough understanding of the inventive concepts and technical solutions of the present invention, including the shapes of the components, the structures, the mutual positions and connection relationships of the components, the functions and operating principles of the components, the manufacturing processes, the operation and use methods, and the like.
FIG. 1 is a prior art non-synchronized GPS update diagram of the present invention; the position of the airplane propagated in the flight management system at the time point of T1 is at A101, the actual position of the airplane at the time point is at A102, the updating at the time point of T1 starts, the updating at the time point of T2 is finished, the flight management system calculates according to the position and the speed of the airplane flying at the time point of A101, the airplane is displayed at A105 at the time point of T2, but the updating is finished, the actual position A102 of the airplane at the time point of T1 is updated to the flight management system, so that the displayed position of the airplane jumps to the updated A104 from the A105 before the updating to the actual position A102 of the airplane at the time point of T1. But now the aircraft has actually flown to a 106; it follows that the presence of a time delay causes an instantaneous jump in the position of the aircraft and the position propagated by the flight management system is subject to a large error from the actual position of the aircraft.
FIG. 2 is a flow chart of the present invention for GPS signal reception; an estimation system for aviation GPS signal delay as shown in the figure comprises a signal receiver (C101) for GPS signal reception and an aviation computing resource partition (C102) in communication connection with the signal receiver, wherein the aviation computing resource partition (C102) comprises a GPS server (C103) and a navigation server (C104), the GPS server (C103) is in communication connection with the navigation server (C104) through a signal interface, and the GPS server (C103) receives GPS signals through the signal receiver (C101) and outputs the GPS signals to the navigation server (C104); the signal receiver (C101) is in communication connection with the GPS server so as to receive the GPS position signal input by the signal receiver (C101) and convert the GPS position signal into a communication signal to be transmitted to the GPS server, the GPS server processes and distributes the received GPS signal to a communication interface connected with the navigation server (C104), and the navigation server (C104) acquires data through the communication interface and uses the data.
The factors for generating the time delay mainly include 4 parts, namely the inherent calculation time of the GPS, namely the time from the signal sending to the processing completion of the receiver; second, the transmission time from GPS receiver to the aviation computing resource partition ACR; thirdly, the time consumed by the GPS server in the ACR to process and update the interface; and fourthly, the time taken for the navigation server in the ACR to read the interface data and use.
The method adopts three steps to estimate the delay time, firstly, the GPS update time is compared with the navigation server update time, one of the delay estimation time is selected to be relatively close to the navigation server update time, secondly, the estimated value △ test of the time delay is added, the influence of unknown delay time is reduced to the maximum extent, and the maximum value of the error is limited in the range of △ test, and thirdly, the optimal time delay estimation strategy is given, which is described in detail below:
comparing GPS update time with navigation server update time
FIG. 3 is a diagram illustrating the delay between GPS updates according to the present invention, wherein △ tGPSB102 is the GPS time elapsed between GPS updates (i.e., the time between GPS time stamps); △ tNavB112 is the ACR time (i.e., message reception interval time) elapsed between navigation server updates, △ t0B110 is the unknown time delay at the first update △ tnB104 is the unknown time delay of the nth update period, △ tacr,0B111 is the time delay measured during the first update (time of the first update the GPS server issues to interface to the navigation server use); △ tacr,nB105 is the time delay measured during the nth update (at which time the GPS server issues to the interface)Time to navigation server usage); t is0B101 is the actual calculated time of the first GPS fix; t isnB103 is the actual calculation time of the nth GPS positioning; t isn+1B106 is the actual usage time of the navigation server receiving the nth GPS fix.
Estimating the actual reception time of the nth GPS fix without including an unknown time delay:
TNav,n＝T0+△tNav+△tacr,0estimating by navigation server time
TGPS,n＝T0+△tGPS+△tacr,n＝Tn+△tacr,nEstimation according to GPS time
Actual time delay:
Tn+1-Tn
estimated time delay, not including unknown time delay:
TNav,n-Tn
error in estimated time:
Tn+1-TNav,n＝△t0estimating by navigation server time
Tn+1-TGPS,n＝△tnEstimation according to GPS time
Difference in estimated time due to elapsed time
TGPS,n-TNav,n＝△t0-△tn
Since the time delay consists of one known and unknown component, the algorithm minimizes the unknown component by comparing the elapsed time between GPS time stamps to the elapsed time between GPS messages used by the navigation server.
If T isGPS,n-TNav,n>0, i.e. △ t0>△tnThen the error estimated as GPS time is smaller and its updated unknown time delay is smaller. Thus, TGPSAnd TNavIn contrast, TGPSThe estimation of the actual time is more accurate, and the time of the navigation server is expressed by TGPS,nSynchronization, the time delay can be further reducedLate estimated error.
On the contrary, if TGPS,n-TNav,n<0, then the error in GPS time estimation is larger because △ t0<△ tn. thus, the time representation T of the navigation serverNav,nIs a more accurate estimate of the actual time because the elapsed time accounts for the increased time delay.
(II) adding an estimate of the time delay △ test
The error in the estimated time is due to the unknown time delay (△ t in FIG. 2)0B110&△tnB104) The effect of this delay can be further reduced by adding an estimate of the time delay △ test, dividing the unknown time delay into two parts, and measuring △ test using observation tests.
1. Principle analysis of increasing △ test
Suppose △ tu,0The portion of the unknown component of the total unknown time delay that is not covered by △ test, then
△t0＝△test+△tu,0Unknown time delay of first update
△tn＝△test+△tu,nUnknown time delay of nth update
Applying the estimated time delay to the GPS updated actual time estimate and its corresponding error to obtain an actual receive time estimate for the nth GPS fix:
TNav,n＝T0+ΔtNav+Δtacr,0+Δtestestimating by navigation server time
TGPS,n＝T0+ΔtGPS+Δtacr,n+ΔtestEstimation according to GPS time
Estimating a time error:
Tn+1-TNav,n＝Δtu,0estimating by navigation server time
Tn+1-TGPS,n＝Δtu,nEstimation according to GPS time
Estimated time difference due to elapsed time:
TGPS,n-TNav,n＝Δtu,0-Δtu,n
if the estimate △ test is close to the actual time delay △ t0&△tnThe error can be significantly reduced and the size of the error is limited to △ test.
Because of Δ tn>＝0&Δtn＝Δtest+Δtu,n,
If Δ tu,n<0,
|Δtu,n|＝<Δtest
Estimation method of △ test
△ test is estimated by empirical data analysis and refinement, collecting recorded data of multiple flight data, comparing actual deviation values of asynchronism between the air data attitude heading reference system ADAHR and the turn of the GPS track in the flight data, calculating the average value of the deviation values, and combining the update cycle of the GPS to obtain the optimal △ test value suitable for the aircraft.
(III) giving an optimal strategy
And (4) the navigation server gives an optimal estimation strategy according to the results of the step (I) and the step (II) to obtain a final delay time estimation value.
By adopting the technical scheme, the passing time between the GPS time stamps is compared with the passing time between the GPS messages used by the navigation server through an algorithm so as to reduce unknown components and reduce the error, T, of the estimation of the GPS timeGPSAnd TNavIn contrast, TGPSThe estimation of the actual time is more accurate, and the time of the navigation server is expressed by TGPS,nBecause the estimated value △ test is added in the algorithm, the influence of unknown delay time is reduced to the maximum extent, and the error value is limited in the estimated value, the estimated GPS signal delay is more accurate, and has a greater auxiliary effect on GPS signal positioning in flight dynamic.
The invention has been described above with reference to the accompanying drawings, it is obvious that the invention is not limited to the specific implementation in the above-described manner, and it is within the scope of the invention to apply the inventive concept and solution to other applications without substantial modification.