-
Home
- Ece 301 projects fall 2003
- Radar simulation in matlab
- Approach for range
Basically M multiplied by L is the entire length of the signal and (M-N) is the last value of the first chirp right on the falling edge.
Characterizing match filter
We characterize the match filter impulse response as being h(t)=s*(-t)=exp(-j*W/T*t^2) with t on the range of [-T/2,T/2]. See
"Background" module under the section"Match Filter"for more details.
Range analysis
The approach taken now to analyze the corresponding range of the target for the received signal is the following:
- Process recieved signal through a match filter with impulse response described above and in"Backgrounds"
- Process originally transmitted signal through same match filter
- Pick out the peaks from outputs via setting a threshold value as a starting point
- Compare the location of the first peak from each output
- The difference in locations of the 1st peaks is the time delay (Td) value
- Plug Td into discrete time range equation to get approximate range
The reason why we only need to analyze the first peak is because we are assuming that the object is not moving. Also, for future work, if the range and velocity systems were to be integrated (i.e. can take into account a moving target ) an initial range would be calculated from the first returned pulse. Velocity would be calculated as well from the rest of the recieved signal. Then, a relationship could be found for the object's range as a function of time. More specifically R(t) = Ro - vt where assuming the target is approaching the radar and since the velocity was calculated the simple distance = rate x time relationship can be used ( where x = multiplication). Note, this is all assuming a constant velocity and that the target is still not at an angle to the radar's transmission path.
The matlab function"
rangecalc "does the above stated list and an exampe of how it is called follows. It is interesting to note that the"rangecalc"function calls a subfunction to actually pick out the peaks in the outputs of the matched filters. The subfunction is called"
pkpicker " "and was provided by the"Computer-Based Exerciese for Signal Processing Using MATLAB"book by Burrus [ et al.]. Given the number of peaks to look for, a threshold value to use, and a vector, the function will go through a vector and will output the locations of the highest peaks above the threshold as well as their values.
Example of"Rangecalc"Matlab function call
[timedelay,range,rsigmatchlocs] = rangecalc(rsig,tsig,h,number,thresh,Ts) with inputs:
with outputs:
- timedelay = difference in location of 1st peaks from outputs of both match filters
- range = corresponding real world target range (units: meters)
- rsigmatchlocs = vector containing locations of peaks from output of match filter of recieved signal
Example of"Pkpicker"Matlab function call
[peaks,locs] = pkpicker( x, thresh, number, sortem ) with inputs:
with outputs:
- peaks : peak values
- locs : location of peaks (index within a column)
Putting it all together
The function that we designed to combine all of the previously mentioned functions is called"
burst4 ".
Example of"Burst4"Matlab function call
[noisytestecho,noisyshifttestecho,rsigmatchlocs,timedelay,range,h] = burst4(L,TW,p,M,n,sampfreq,TD) with inputs:
with outputs:
- noisytestecho: noisy burst waveform of L lfm chirps of the same TW,p
- noisyshifttestecho: shifted (i.e. time-delayed) of noisy burst waveform
- rsigmatchlocs: vector containing locations of peaks from output of match filter of recieved signal
- timedelay: difference in location of 1st peaks from outputs of both match filters
- range: real world target range (units: meters)
- h: impulse response for match filter
Method of comparison
Using the"
radar "function provided by"Computer-Based Exerciese for Signal Processing Using MATLAB"by Burrus [ et al.] (see page 328 of book for full explanation of usage) we were able to compare our simulated returned signal.
Range equation
Range equation (continuous time)
Characteristics of continous-time range equation
The equation is designed for continuous time signal where the two parameters are:
- Td = time delay between transmitted signal and recieved signal
- c = speed of light (3 x 10^8 m/s) (where x = multiplication)
Range equation (discrete time)
Characteristics of discrete-time range equation
The equation that matlab will have to use to calculate range and get corresponding real world values from three paramters:
- Td = difference in terms of actual physical location of the same value in 2 vectors
- c = speed of light (3 x 10^8 m/s) (where x = multiplication)
- Ts = 1/sampling frequency (used to create LFM chirp from beginning)
Where to next
Next, look at
"Range Results" as next step.
Questions & Answers
A golfer on a fairway is 70 m away from the green, which sits below the level of the fairway by 20 m. If the golfer hits the ball at an angle of 40° with an initial speed of 20 m/s, how close to the green does she come?
A mouse of mass 200 g falls 100 m down a vertical mine shaft and lands at the bottom with a speed of 8.0 m/s. During its fall, how much work is done on the mouse by air resistance
Can you compute that for me. Ty
Jude
what is the dimension formula of energy?
Chemistry is a branch of science that deals with the study of matter,it composition,it structure and the changes it undergoes
Adjei
please, I'm a physics student and I need help in physics
Adjanou
chemistry could also be understood like the sexual attraction/repulsion of the male and female elements. the reaction varies depending on the energy differences of each given gender. + masculine -female.
Pedro
A ball is thrown straight up.it passes a 2.0m high window 7.50 m off the ground on it path up and takes 1.30 s to go past the window.what was the ball initial velocity
2. A sled plus passenger with total mass 50 kg is pulled 20 m across the snow (0.20) at constant velocity by a force directed 25° above the horizontal. Calculate (a) the work of the applied force, (b) the work of friction, and (c) the total work.
you have been hired as an espert witness in a court case involving an automobile accident. the accident involved car A of mass 1500kg which crashed into stationary car B of mass 1100kg. the driver of car A applied his brakes 15 m before he skidded and crashed into car B. after the collision, car A s
can someone explain to me, an ignorant high school student, why the trend of the graph doesn't follow the fact that the higher frequency a sound wave is, the more power it is, hence, making me think the phons output would follow this general trend?
Nevermind i just realied that the graph is the phons output for a person with normal hearing and not just the phons output of the sound waves power, I should read the entire thing next time
Joseph
Follow up question, does anyone know where I can find a graph that accuretly depicts the actual relative "power" output of sound over its frequency instead of just humans hearing
Joseph
"Generation of electrical energy from sound energy | IEEE Conference Publication | IEEE Xplore" ***ieeexplore.ieee.org/document/7150687?reload=true
Ryan
what are the types of wave
Maurice
fine, how about you?
Mohammed
A string is 3.00 m long with a mass of 5.00 g. The string is held taut with a tension of 500.00 N applied to the string. A pulse is sent down the string. How long does it take the pulse to travel the 3.00 m of the string?
Who can show me the full solution in this problem?
Got questions? Join the online conversation and get instant answers!
Source:
OpenStax, Ece 301 projects fall 2003. OpenStax CNX. Jan 22, 2004 Download for free at http://cnx.org/content/col10223/1.5
Google Play and the Google Play logo are trademarks of Google Inc.
