CN103198666A - Highway traffic stream space average speed observation method based on fixed wing model airplane - Google Patents

Abstract

The invention discloses a highway traffic flow space average speed observation method based on a fixed wing model airplane. The method is applied to the fixed wing model airplane with specific functions flying in a fixed height, evenly and in an inverse traffic stream direction, photographic equipment is carried to take traffic stream photos at specific time intervals, photos of the measured and calculated space are extracted, vehicle changing numbers in two adjacent photos are counted, data of relative vehicle streams, traffic stream density, time intervals, relative speeds and the like are obtained, and then space average speed is calculated and obtained. The highway traffic stream space average speed observation method based on the fixed wing model airplane is simple, fast and convenient, observation results are reasonable and reliable, and the problem that an existing method cannot directly measure and calculate the space average speed is solved.

Description

A kind of highway communication fluid space average speed observation procedure based on the fixed-wing model plane

Technical field

The present invention relates to a kind of highway communication fluid space average speed observation procedure.

Background technology

Space mean speed refers in a certain specified moment, exercises the mean value of the speed of a motor vehicle distribution of the rolling stock in a certain length-specific of road.Space mean speed is an important control index in the roading design, is again a main evaluation index of car operation efficient, for transportation economics, safe, fast, comfortable significant.

Because all vehicles are in diverse location on the synchronization path space, classic method is difficult to measure simultaneously the speed separately of all vehicles, therefore select for use the harmonic-mean of the place speed of a motor vehicle (by the instantaneous speed of a motor vehicle of a certain observation place) observed reading to come the approximation space average speed usually, and have certain error between the actual value.

Summary of the invention

Technical matters: obtain loaded down with trivial details, direct weak points such as computer memory average speed, accuracy error for overcoming existing space average speed observation procedure data, the invention provides a kind of data obtain convenient, energy is computer memory average velocity accurately, the more reasonable reliable highway communication space mean speed observation procedure based on the fixed-wing model plane of result.

Technical scheme: the highway communication fluid space average speed observation procedure based on the fixed-wing model plane that the present invention proposes, what comprise time interval of carrying out successively asks for step, traffic flow data sampling step and highway communication fluid space average speed calculation procedure:

Wherein, the step of asking in the above-mentioned time interval specifically comprises:

Step 1: set the basic parameter that aviation is taken, obtain the design speed V of observation road simultaneously _d, the basic parameter that aviation is taken comprises model plane flying height H, stable flying speed V _aAnd the wide-angle α of digital camera;

Step 2: according to model plane flying speed V _aWith the highway layout vehicle velocity V _dBe calculated as follows relative velocity V _r:

V _r=V _a+V _d

In the formula, V _aBe the model plane flying speed, the km/h of unit, V _dBe the highway layout speed of a motor vehicle, the km/h of unit, V _rBe the relative velocity of model plane and wagon flow, the km/h of unit;

Step 3: the physical length L that is calculated as follows the interior road of photo of model plane shooting:

L=2H?tan(α/2)

In the formula, L is the physical length of road in the photo, the m of unit, and H is the height of taking photo by plane, the m of unit, α are the camera wide-angle;

Step 4: with the real road length L 1/3 divided by relative velocity V _r, obtaining the initial time interval T, computing method are as follows:

$T=\frac{L}{{3V}_r}\×\frac{3600}{1000}=\frac{1.2L}{V_r}$

In the formula, T is the initial time interval, the s of unit,

After calculating the initial time interval T, T is carried out round, obtain the time interval T of final integer form ^*

The fixed-wing model airplane of the traffic flow data sampling step application is integrated front end camera, digital camera, GPS module, flight control module and image transmission module is as the scope carrier, the front end environment image of the front end camera real time record model plane of fixed-wing model airplane flight, and by image transmission module image is sent to surface-monitoring equipment; Terrestrial operation person observes the flight environment of vehicle of model airplane by surface-monitoring equipment, and send the flight steering order by surface-monitoring equipment to model airplane, the flight of control model airplane is to waiting to observe the road sky, with speed of a ship or plane Va and the height H contrary traffic flow direct of travel flight of setting along the track; In the model airplane flight course, the digital camera of lift-launch is straight down with time T ^*Be that the time interval takes the road traffic flow photo continuously, and it is pending that captured photo is sent to surface-monitoring equipment etc. by image transmission module;

Highway communication fluid space average speed calculation procedure specifically comprises:

1) specify observation t1 constantly, check the vehicle fleet N in the t1 model plane shooting constantly highway photo, the imperfect vehicle conversion that all observe in the picture is 0.5; Then, at t1+T ^*Check t1+T in the highway photo that model plane are taken constantly ^*Constantly relative t1 rolls the vehicle fleet n of photo picture constantly away from, is 0.5 for incomplete vehicle conversion;

2) the physical length L of road in vehicle fleet N and the photo calculated t1 traffic density K constantly in model plane were taken pictures constantly according to t1, and computing formula is as follows:

$K=\frac{1000N}{L}$

In the formula, K is traffic density, unit/km, and N is the t1 model plane interior vehicle fleet of taking pictures constantly, unit, L is the physical length of road in the photo, the m of unit;

3) ask for time interval T ^*Relative hour flow rate Q of interior traffic flow, computing formula is as follows:

$Q=\frac{3600n}{T^{*}}$

In the formula, Q is relative hour flow rate, unit/h, and n is t1+T ^*Constantly relative t1 rolls the vehicle fleet of photo picture, the h of unit, T constantly away from ^*Be the time interval, the s of unit;

4) according to traffic flow three parameter-definition relational expressions, ask for the space average velocity V of t1 traffic flow constantly _R, computing formula is as follows:

$V_R=\frac{Q}{K}=\frac{3.6\mathrm{nL}}{{\mathrm{NT}}^{*}}=\frac{7.2\mathrm{nH}\tan (\mathrm{\α}/2)}{{\mathrm{NT}}^{*}}$

In the formula, V _RBe space average velocity, the km/h of unit;

5) try to achieve actual traffic stream at t1 space mean speed constantly by the relative wagon flow speed with model plane of the speed of model plane; Computing formula is as follows:

$V_S=V_R-V_a=\frac{7.2\mathrm{nH}\tan (\mathrm{\α}/2)}{{\mathrm{NT}}^{*}}-V_a$

In the formula, V _SFor actual traffic flows the space mean speed constantly at t1, the km/h of unit.

Beneficial effect: the present invention compared with prior art has the following advantages:

Because all vehicles are in diverse location on the synchronization path space, classic method is difficult to measure simultaneously the speed separately of all vehicles, therefore select for use the harmonic-mean of the place speed of a motor vehicle (by the instantaneous speed of a motor vehicle of a certain observation place) observed reading to come the approximation space average speed usually, accuracy error is big, and data are obtained loaded down with trivial details.And the present invention can observe the locus of all vehicles in the zone, by the direct computer memory average velocity of traffic flow three parameter-definition formulas, does not need approximate estimation, and the result is more reasonable reliable, and data obtain convenient.

Description of drawings

Fig. 1 is the logical flow chart of the inventive method.

Fig. 2 is t1 aerial photograph signal constantly.

Fig. 3 is t1+T ^*Aerial photograph signal constantly.

Embodiment

Below in conjunction with description of drawings application case of the present invention is made into detailed description, but present case is not limited to the present invention, everyly is similar to method of the present invention, all should list protection scope of the present invention in.

Certain the two-way six-lane Class II highway half range road that with the design rate is 60km/h is that example is observed unidirectional space mean speed:

One, determines time interval T ^*

Step 1: set the basic parameter that aviation is taken, obtain the design speed of observation road simultaneously: flying height H is 200m, flying speed V _aBe 80km/h, digital camera wide-angle α is 62 °, the design speed V of road _dBe 60km/h;

Step 2: according to model plane flying speed V _aWith the highway layout vehicle velocity V _dBe calculated as follows relative velocity V _r:

V _r=V _α+V _d=80+60=140km/h

Step 3: the physical length L that calculates the interior road of photo of model plane shooting:

L=2Htan(α/2)=2×200×tan31°=240.3m

Step 4: with the real road length L 1/3 divided by relative velocity V _r, obtain the initial time interval T:

$T=\frac{L}{{3V}_r}\×\frac{3600}{1000}=\frac{1.2L}{V_r}=\frac{1.2\×240.3}{140}=2.06S$

After calculating the initial time interval T, T is carried out round, obtain the time interval T of final integer form ^*Be 2s.

Two, traffic flow data sampling

Application integration front end camera, digital camera (TX20, camera wide-angle 62 degree), the fixed-wing model airplane (skywalker 168) of GPS module (MTK), flight control module (APM2.5) and image transmission module (Luo Mei 2.4G, 1W) is as the scope carrier, the front end environment image of the front end camera real time record model plane of described fixed-wing model airplane flight, and by image transmission module image is sent to ground monitoring system (missionplanner).Terrestrial operation person observes the flight environment of vehicle of model airplane by surface-monitoring equipment, and send the flight steering order by surface-monitoring equipment to model airplane, the flight of control model airplane is to waiting to observe the road sky, with speed of a ship or plane 80km/h and the height 200m contrary traffic flow direct of travel flight of setting along the track.In the model airplane flight course, the digital camera of lift-launch is the time interval to take the road traffic flow photo continuously straight down with 2s.After taking end, extract photo and carry out analyzing and processing.

Three, calculate highway communication fluid space average speed

1) browse photo, seek the best picture corresponding with the target observation highway section, the time t1 of record this moment, shown in Fig. 2,3, check t1 constantly in the photo picture the initial vehicle number N of the wagon flow direction of observing and t1+T ^*The constantly equidirectional t1 of rolling away from the vehicle number n(of photo picture constantly asks for indirectly by differentiating the vehicle number that does not roll picture away from), for t1 and t1+T ^*Constantly in the photo picture incomplete vehicle number average by half counting: for t1 picture shot constantly, there are 6 complete vehicles in equidirectional three tracks on every track, and complete vehicle invariably in the whole image is so the total vehicle number N in conversion back is 18.For t1+T ^*Constantly, the vehicle number that relative t1 does not roll picture constantly away from is complete 12, so the complete vehicle number that rolls away from is 6, incomplete vehicle number is 0, does not need to calculate the vehicle that sails into from the picture rear portion, so conversion back outgoing vehicles sum n is 6.

2) the physical length L of road in vehicle fleet N and the photo in model plane are taken pictures constantly according to t1, calculate t1 traffic density K constantly:

$K=\frac{1000N}{L}=\frac{1000\×18}{240.3}=74.9\mathrm{veh}/\mathrm{km}$

3) ask for time interval T ^*Relative hour flow rate Q of interior traffic flow:

$Q=\frac{3600n}{T^{*}}=\frac{3600\×6}{2}=10800\mathrm{veh}/h$

4) according to traffic flow three parameter-definition relational expressions, ask for the space average velocity V of t1 traffic flow constantly _R:

$V_R=\frac{Q}{K}=\frac{10800}{74.9}=144.2\mathrm{km}/h$

5) try to achieve actual traffic stream at t1 space mean speed constantly: V by the relative wagon flow speed with model plane of the speed of model plane _S=V _R-V _α=144.2-80=64.2km/h.

Claims (1)

1. One kind based on highway communication fluid space average speed observation procedure, it is characterized in that what this method comprised time interval of carrying out successively asks for step, traffic flow data sampling step and highway communication fluid space average speed calculation procedure;

   The step of asking in the described time interval specifically comprises:

   Step 1: set the basic parameter that aviation is taken, obtain the design speed V of observation road simultaneously _d, the basic parameter that described aviation is taken comprises model plane flying height H, stable flying speed V _aAnd the wide-angle α of digital camera;

   Step 2: according to model plane flying speed V _aWith the highway layout vehicle velocity V _dBe calculated as follows relative velocity V _r:

   V _r=V _a+V _d

   In the formula, V _aBe the model plane flying speed, the km/h of unit, V _dBe the highway layout speed of a motor vehicle, the km/h of unit, V _rBe the relative velocity of model plane and wagon flow, the km/h of unit;

   Step 3: the physical length L that is calculated as follows the interior road of photo of model plane shooting:

   L=2Htan(α/2)

   In the formula, L is the physical length of road in the photo, the m of unit, and H is the height of taking photo by plane, the m of unit, α are the camera wide-angle;

   Step 4: with the real road length L 1/3 divided by relative velocity V _r, obtaining the initial time interval T, computing method are as follows:

   $T=\frac{L}{{3V}_r}\×\frac{3600}{1000}=\frac{1.2L}{V_r}$

   In the formula, T is the initial time interval, the s of unit,

   After calculating the initial time interval T, T is carried out round, obtain the time interval T of final integer form ^*

   The fixed-wing model airplane of described traffic flow data sampling step application is integrated front end camera, digital camera, GPS module, flight control module and image transmission module is as the scope carrier, the front end environment image of the front end camera real time record model plane of described fixed-wing model airplane flight, and by image transmission module image is sent to surface-monitoring equipment; Terrestrial operation person observes the flight environment of vehicle of model airplane by surface-monitoring equipment, and send the flight steering order by surface-monitoring equipment to model airplane, the flight of control model airplane is to waiting to observe the road sky, with speed of a ship or plane Va and the height H contrary traffic flow direct of travel flight of setting along the track; In the model airplane flight course, the digital camera of lift-launch is straight down with time T ^*Be that the time interval takes the road traffic flow photo continuously, and it is pending that captured photo is sent to surface-monitoring equipment etc. by image transmission module;

   Described highway communication fluid space average speed calculation procedure specifically comprises:

   1) specify observation t1 constantly, check the vehicle fleet N in the t1 model plane shooting constantly highway photo, the imperfect vehicle conversion that all observe in the picture is 0.5; Then, at t1+T ^*Check t1+T in the highway photo that model plane are taken constantly ^*Constantly relative t1 rolls the vehicle fleet n of photo picture constantly away from, is 0.5 for incomplete vehicle conversion;

   2) the physical length L of road in vehicle fleet N and the photo calculated t1 traffic density K constantly in model plane were taken pictures constantly according to t1, and computing formula is as follows:

   $K=\frac{1000N}{L}$

   In the formula, K is traffic density, unit/km, and N is the t1 model plane interior vehicle fleet of taking pictures constantly, unit, L is the physical length of road in the photo, the m of unit;

   3) ask for time interval T ^*Relative hour flow rate Q of interior traffic flow, computing formula is as follows:

   $Q=\frac{3600n}{T^{*}}$

   In the formula, Q is relative hour flow rate, unit/hour, and n is t1+T ^*Constantly relatively t1 rolls the vehicle fleet of photo picture constantly away from, unit, T ^*Be the time interval, the s of unit;

   4) according to traffic flow three parameter-definition relational expressions, ask for the space average velocity V of t1 traffic flow constantly _R, computing formula is as follows:

   $V_R=\frac{Q}{K}=\frac{3.6\mathrm{nL}}{{\mathrm{NT}}^{*}}=\frac{7.2\mathrm{nH}\tan (\mathrm{\α}/2)}{{\mathrm{NT}}^{*}}$

   In the formula, V _RBe space average velocity, the km/h of unit;

   5) try to achieve actual traffic stream at t1 space mean speed constantly by the relative wagon flow speed with model plane of the speed of model plane; Computing formula is as follows:

   $V_S=V_R-V_a=\frac{7.2\mathrm{nH}\tan (\mathrm{\α}/2)}{{\mathrm{NT}}^{*}}-V_a$

   In the formula, V _SFor actual traffic flows the space mean speed constantly at t1, the km/h of unit.

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