Feasibility of Pulsed Radar System for Autonomous Driving - Calculation-Based Questions

Please answer each question below with relevant calculations and written comments, opinions and judgements, No Matiab programmes are required for this assignment. Please show all your working, rather than just the answer you arrive at, as marks may be awarded for partially correct answers. You may use the equation editor in Word to type calculations, but this is not a requirement.

Marks will not be awarded for typographical neatness, but for darity of expression. 5o 'P.,. and i'Pmln Is proportional to 13,4). will be assessed equally; the marks will !seaward. as long as h is an accurate expression, relevant to the particular question and Pmin and R are properly defined. There is no minimum or maximum word count required. The work will be assessed on the relevance and accuracy of the answers you provide.

Marks will be awarded for mentioning the relevant facts and thinking through the problem and using your judgement, rather than precision.

Questions 1-13 require numerical answers, rather than just equations or 'It depends on._'.

The company British Motor Utilities Unlimited BMUU, wishes to develop a pulsed radar system for use In autonomous and/or drimr-assisted cars. BMUU have employed a specialist /that's you, to assess the feasibility of the radar system. In particular, they would like to know whether a system can be built with the following specifications:

• The radar should be able to see oncoming vehicles three seconds before they pass the ego vehicle (the vehicle which has the radar installed), allowing evasive action, such ...king, if necessary.
• The radar should be able to detect a pedestrian at its maximum range.
• The radar should still work when in proximity to 100 other similar radar systems.
• The average ',Meer required for radar operation should not exceed 100 watts.
• Target vehicles should not move more than 8m between sweeps of the radar.
• The radar should fit within a 25 cm cube.
• The minimum SNR to Identify a target should be 20 dB.
• The radar will work within the band of frequencies designated for medium-range vehicle radar systems, namely 77.0— 81.0 Glie and will switch Its operating frequency within that band to avoid interference from other vehicle radar systems.

All Questions carry equal weight and will be marked using the following mark-scheme.

No understandable answer=0;

attempted but wrong=1;

reasonable attempt=2;

complete and intelligent answer=3

Q1.

Consider 90 mph as the maximum speed of vehicles and from this, estimate the maximum range needed for this radar system.

Q2.

What Is the approximate wavelength of the carrier wave?

Q3.

By considering the radar aperture and wavelength, estimate the maximum gain that could be achieved.

Q4.

Estimate the spectral noise density for a temperature of 27°C.

Q5.

By considering interference from other automotive radar systems, suggest a suitable bandwidth for the radar system.

Q6.

The radar receiver has a noise figure of 10dB. What would be the minimum received signal power that could be detected above the nolse7

Q7.

Estimate the bearnwidth. Assume half of the total power of the radar Is directed into the main beam, which is b radians wide in azimuth and b radians wide in elevation. calculate the beamwithh, given the your gain value and the equation: Gain = 0.5140/(6.2). Convert this value to degrees.

Q8.

Estimate the resolution in azimuth (in metres) at the maximum range defined in Q1.

Q9.

Assuming the radar rotates 360° in azimuth and the elevation is constant, suggest a reasonable rotation rate.

Q10.

 What would the dwell time be?

Q11.

Given the bandwidth you calculated, what is the approximate minimum pulse width,

Q12.

Estimate the range resolution. Does this depend on the targets range?

Q13.

Given that at least 4 hits per scan are required for clarity, what would you choose for the pulse repetition time?