Measurement accuracy
The maximum error (error) in the distance data issued by the parking sensors during operation. Simply put, this is a plus or minus figure that must be assigned to the indicator data in the practical application of the radar (if a digital indication is provided at all, see "Functions / Capabilities"). For example, if an accuracy of 5 cm is specified, then if the display reads 50 cm, the actual distance from the sensor to the obstacle can be anything between 45 and 55 cm inclusive.
Note that there is nothing wrong with the very existence of an error — it cannot be completely eliminated even in the most advanced devices. Therefore, we are only talking about its meaning: the smaller the number indicated in this paragraph, the more accurate the readings of the parking sensors will be. High accuracy is especially important if you have to manoeuvre in very tight spaces where distances often approach the value of the minimum detection distance (see below). In this regard, also note that the claimed error values are relevant only for the operating range of distances.
Scan distance
Working distance range of parking sensors; in other words, this is the interval from the response threshold to the smallest distance at which the device is still able to provide sufficiently reliable data on the distance to the obstacle.
The threshold of operation of modern devices usually does not exceed 3 m, and more often it is in the range of 1.5 – 2.5 m; the sensors themselves are capable of providing a longer range, but in fact there would be little benefit from this, but there are plenty of reasons for unnecessary worries. The minimum distance, usually, is 0.1-0.3 m (10-30 cm); a closer entrance is usually perceived by the device as a close approach, with a corresponding indication (for example, the transition of the sound signal to continuous). And if the response threshold is more of a reference value, then you should pay closer attention to the minimum distance, especially if you often have to deal with cramped conditions (for example, manoeuvring at a difficult entrance to a small garage). Indeed, in such cases, it is important that the parking sensors retain the ability to accurately indicate the distance for as long as possible, without switching to the “close” mode.
Sensors diameter
The diameter of the sensors supplied as standard with the parking radar is an important parameter when installing them: it determines the size of the landing slots, in other words, the holes in the bumper. Many parking sensors are equipped with a special cutter for drilling such sockets — it optimally matches the diameter of the complete sensors, and in this case this parameter actually becomes irrelevant. However, if there is no cutter in the kit, you will not be able to select the drill of the right size without information about the diameter. Also, this information will be very useful if you install parking sensors on a car with existing holes in the bumper (for example, if the previous radar did not suit you according to its characteristics): by choosing a model with the same sensor diameter, you can install them directly into ready-made sockets, without too much fiddling with the fit. So the most popular
sensor size is 18 mm, but there are
19,
20,
21 and
22 mm. In this case, often in each option there is a deviation of half a millimetre.
