Under-vehicle surveillance systems (UVSS) at port gates: how they work and what to specify

What is a UVSS and what does it show?

A UVSS takes pictures of the underside of a vehicle while it drives over a scanning unit. Software joins the pictures into one composite image of the whole under-body. A guard looks at that image on a screen to spot anything that should not be there, such as a package taped near the fuel tank or a hidden space.

It does not open the vehicle or see inside solid parts. It shows surfaces that a camera can see from below.

Port specifications pair the UVSS with two more cameras. One reads the number plate (ANPR). One photographs the driver. New Mangalore Port Authority's 2024 specification asks for a "UVSS-ANPR system at entry and exit of all gates" with a driver image camera. V.O. Chidambaranar Port Authority's 2026 tender asks that the under-body image, driver photo, front image and plate all show "almost instantaneously". So a guard sees one record per vehicle, not three separate feeds.

What do the security rules ask for?

No rule we found names a UVSS. The rules ask for vehicle checks and searches, and leave the method to the port facility security plan (PFSP). The text below is from the ISPS Code as reproduced in EU Regulation 725/2004. That text defines the Code as Part A, "treated as mandatory", and Part B, "treated as recommendatory".

Part A, section 14.2, says that at security level 1 certain activities "shall be carried out through appropriate measures in all port facilities". The list includes "controlling access to the port facility".

Part B gives the detail. Paragraph 16.14 says the PFSP should name where person and vehicle searches happen, and that these places "should be covered to facilitate continuous operation, regardless of prevailing weather conditions". That matters for a UVSS: a covered lane keeps rain off the scanner and the guard. Paragraph 16.17 lists "checking vehicles used by those seeking entry to the port facility in connection with a ship" and "undertaking searches of persons, personal effects, vehicles and their contents". Paragraph 16.18 says that at level 1, "all those seeking access to the port facility should be liable to search."

The search grows with the threat. At level 2, paragraph 16.19 adds "increasing the frequency of searches of persons, personal effects, and vehicles". For cargo handling, paragraph 16.32 lists "searches of vehicles" at level 1 and paragraph 16.35 lists "intensified searches of vehicles" at level 2. Paragraph 16.33 says cargo checks may use "scanning/detection equipment, mechanical devices, or dogs." At level 3, the port facility "should comply with instructions issued by those responding to the security incident or threat thereof."

India's own port security rules are covered in our note on BoPS and ISPS rules in India. We could not fetch the official text of the 2026 rules for this page, so we quote none of their clauses here.

Area-scan or line-scan, in-ground or surface-mounted?

There are two ways to build the image. A line-scan camera records one thin strip at a time and stacks the strips as the vehicle moves. An area-scan camera takes full frames and the software stitches them. With either one, the software has to know how fast the vehicle is moving, or the image stretches or squashes.

Both Indian port specs we read choose area-scan. New Mangalore's says the UVSS "should not use either a digital Line-Scan camera-based technology or any type of analog cameras to form composite image". It also asks for a clean image "even when a vehicle completely stops / halts over the scanning unit". Both specs use induction loops to measure speed and adjust the image to it.

The second choice is how the unit is fitted. An in-ground unit sits in a pit under a cover. A surface-mounted unit sits on the road like a low ramp. New Mangalore's spec is for a pit, with a pump to drain it. V.O. Chidambaranar's says the unit "should be surface mounted to avoid any kind of water logging or maintenance issue."

Where does the UVSS sit in the gate lane?

Put the UVSS before the barrier, in a straight part of the lane where vehicles drive slowly and in line. One workable order is: loop to detect the vehicle, plate camera, UVSS unit and driver camera, then the guard post and the barrier. V.O. Chidambaranar's ALPR starts when the system detects "a four-wheeler approaching the installed location by means of inductive loops."

Link the barrier to the UVSS, so a vehicle cannot pass before its image is checked. New Mangalore's scope includes integrating the existing boom barriers, with "Infrared Beam set, PE sensor & Push Button", and supplying traffic light signals at each gate. Its spec also asks the UVSS to work with "boom barrier/bollard/tyre killer/RFID" and to run in "free flow mode, security mode and emergency mode".

Plan for heavy traffic. A port gate takes trucks and trailers as well as cars. Both specs ask for a 20 tonne rating. Check that the lane width, the turning space before the unit and the ramp height suit the longest vehicle the gate takes. Our page on port gate automation covers lane layout and exception lanes in more depth.

How does a UVSS connect to ANPR and the ICCC?

The plate number is the key that ties everything together. It links today's under-body image to past images of the same vehicle and to any watch list. V.O. Chidambaranar's ALPR lets authorised staff mark plates as "Wanted", "Suspicious", "Stolen" or "Expired" and alerts the control room when one is read. It also lets an operator correct a misread plate by hand. Our note on ANPR accuracy explains why plates get misread.

Comparison with a reference image is what makes a UVSS more than a camera. New Mangalore's spec asks the system to compare the left and right views against a "license plate/type database of underside images" and to use AI to compare the vehicle with its standard model and "highlight the differences of original make and present vehicle with Audio and Video alert."

Send each UVSS event to the port's command centre as one record: time, lane, plate, images, alert and the guard's decision. New Mangalore's request puts the UVSS, CCTV and a video wall in one scope, and asks for an NTP server, so every device keeps the same time. In India, CERT-In's 2022 directions require organisations to sync ICT system clocks with NIC or NPL time servers, or servers traceable to them. They also require logs of all ICT systems to be kept "for a rolling period of 180 days" within India, and listed incidents reported within 6 hours.

What should a UVSS specification include?

Use the two port specs as a starting point, then write each item so it can be tested on site.

• Speed range, from a full stop up to the lane's top speed, with an image that stays clear if the vehicle stops or changes speed
• Camera type and resolution, and the size of the composite image
• In-ground or surface-mounted, chosen from the site's drainage, traffic and civil work limits
• Load rating for the heaviest axle the gate takes, at any point on the unit
• IP 68 sealing with a test certificate from an accredited Indian lab, and automatic cleaning of the camera window
• ANPR and driver camera in the same record, with manual plate correction and a watch list
• Comparison with past images of the same plate, and with a reference image for the vehicle model
• Links to the boom barrier and the command centre, with the operating modes written down
• How long images and logs are kept and where, sized in TB, with time sync to NIC or NPL
• Uptime target and penalties; V.O. Chidambaranar sets 95% availability for its scanners
• Lightning protection, and training for the security force that will run it

What goes wrong with UVSS at ports?

Many failures come from the site, not the camera. The specs show what ports have learned to ask for.

• Water: a pit fills in the monsoon. New Mangalore asks for an automatic pump; V.O. Chidambaranar chose a surface unit to avoid water logging
• Dirt: dust and mud cover the camera window. Both specs ask for automatic air or water cleaning
• Lightning: V.O. Chidambaranar calls its site "a high lightning zone" and asks for lightning arrest
• Stop-and-go traffic: a truck that stops on the unit can blur a poor image. Both specs ask for a clean image even when the vehicle stops
• Light: changing daylight at the lane edge spoils the image. V.O. Chidambaranar asks the system to adjust brightness and contrast automatically; New Mangalore rejects halogen or CFL lighting
• No reference image: without past scans of the same plate, a guard has nothing to compare against on a first visit
• No rule for the guard: the PFSP should say what happens when the image looks wrong, who checks the vehicle, and where it waits

How Ahuva approaches gate security

Ports and maritime is one of the sectors Ahuva serves. Its surveillance line covers IP surveillance, AI/ML analytics and ANPR on a centralised VMS. Its access control line covers turnstiles, boom barriers and visitor management, integrated with CCTV. Its ICCC / CCC line covers command centre design and the integration of CCTV and analytics.