Remote Parking Assist (RPA)

Remote Parking Assist (RPA) is an advanced driver assistance feature that allows the driver, while outside the vehicle, to manoeuvre the car autonomously into or out of a parking bay using a smartphone app or smart key. Designed primarily to overcome the hassle of tight parking bays where opening doors becomes difficult, RPA serves as a crucial transitional stepping stone from Autonomous Parking Assist (APA) toward fully driverless automated parking.

Working Principle and System Architecture

In terms of hardware, RPA shares a similar setup with APA, relying mainly on peripheral sensors such as ultrasonic sensors (12 units comprising 8 short-range UPA and 4 long-range APA sensors) alongside 360-degree surround-view cameras to monitor vehicle surroundings. Higher-end variants may incorporate millimetre-wave radars or LiDAR sensors to enhance spatial detection accuracy. The key differentiator is the integration of a Bluetooth communication module, which establishes a wireless link between the smartphone app and the vehicle’s onboard Bluetooth (typically within an effective range of 10 to 20 metres) to enable seamless out-of-car remote parking control.

RPA operates on a closed-loop "sense-plan-act" framework: the system detects available parking bays via sensors, the RPA control unit plots the trajectory, and commands are sent to execution modules like Electric Power Steering (EPS), brake-by-wire, drive motor, and shift-by-wire (TCU) via the drive-by-wire chassis to autonomously manage steering, throttle, braking, and gear selection. Certain models require the driver to complete an in-app safety tutorial video and assessment prior to initial activation, ensuring a clear understanding of the system's operational limits.

Key Operating Modes

RPA typically offers three primary functions:

• Remote Straight-line Manoeuvre: The driver guides the vehicle straight forward or backward from outside the car, ideal for fetching items from tight parking spots or making minor parking adjustments.

• Remote Park-in: The driver initiates the system and confirms the bay while inside the car, engages Park (P) mode and the electronic parking brake (EPB), exits the vehicle, and triggers the park-in sequence via the app. The car then manoeuvres into perpendicular, parallel, or diagonal parking bays autonomously.

• Remote Park-out: When parked, the driver can remotely command the vehicle to drive out of the bay using the app without stepping inside, eliminating the difficulty of getting into a tightly parked vehicle.

Industry Landscape

RPA adoption is growing rapidly across the automotive sector. Data indicates that in 2024, RPA installations in the Chinese market reached 4.529 million units, charting a 91% year-on-year surge. Multiple carmakers have rolled out this feature in mass-production models, including BYD, Changan, GAC Trumpchi, and SAIC Volkswagen.

Operating Limitations and Safety Boundaries

As a driver assistance system rather than fully autonomous driving, RPA operates under clear physical and safety constraints:

• Speed Limit: The vehicle operates at a maximum speed of around 5 km/h during automated manoeuvres to ensure safety.

• Operating Distance: A standing distance of 2 to 6 metres from the vehicle is recommended to keep the car within direct line of sight at all times.

• Driver Responsibility: RPA does not replace visual checks. Drivers must stay alert to sensor blind-spot hazards such as children, pets, or low obstacles like kerbs and bollards. Releasing the control button on the app will immediately halt the vehicle.

• Restricted Conditions: RPA must not be used on extreme surfaces such as icy, wet, slippery roads, steep gradients, or unpaved gravel tracks, as compromised tyre traction can cause the vehicle to deviate from its calculated path and lead to collisions.

• Connectivity Reliability: Phone performance and Bluetooth signal strength can affect operation; the system will automatically pause parking manoeuvres if the app lags or the connection drops.

Important Note: RPA is strictly a parking aid and does not substitute driver judgment and accountability. The driver remains fully responsible for safety throughout the manoeuvre, and improper use may lead to vehicle damage or personal injury.