Radbeacon x4 range android#
As the blog page explains, Android 8.1 requires a filter in order to work. In fact, I believe the example on the page is incorrect, since it sets up the regionBootstrap without any filtering. While I can make the "Monitoring" example work (thus making sure there are not layout issues etc), I cannot for the life of me make the fast beacon detection work. My understanding is the "Starting an App in the Background" example on this page allows the set-up of the fast beacon detection. Instead of doing it from scratch I am using the latest beacon library linked on the page.
Radbeacon x4 range how to#
Fast beacon detection in this context simply means that I want the beacons to be detected even when the app is not running or is in the background, similarly how to iOS detects beacons on a hardware level once you specify the regions. However, good radar detector should be able to detect a radar before the radar detects the vehicle, but not always.I am trying to implement the fast beacon detection by David G Young as shown here under Android 8.1. The radar has the advantage of a much larger antenna (more gain) and more sensitive (to radar signal) receiver. Radar propagation loss is proportional to 1/R 4 (2-way signal path), while a radar detector would be picking up the signal on the direct (1-way) path with loss proportional to 1/R 2 (a hugh advantage for the detector).Īnother hugh advantage is the radar is receiving a reflection (RCS), most of the reflective energy is directed away from the radar. By substituting radar detector minimum signal for power received, detector maximum range can be estimated if radar power and antenna gain are known (ERP - effective radiated power). Signal power received (by a radar detector), where G det is detector antenna gain, can be expressed as shown below. Radio communications range losses are inversely proportional to range squared (one-way path is 1/R 2). Radar has a range loss inversely proportional to range to the 4th power (1/R 4). The radar range equation above can be written for power received as a function of range for a given transmit power, wavelength, antenna gain, and RCS. The available input thermal noise power ( background noise) is proportional to the product kTB where k is Boltzmann's constant, T is temperature (degrees Kelvin) and B is receiver noise bandwidth (approximately receiver bandwidth) in hertz. (S/N) min = Minimum Signal to Noise Ratio K = Blotzmann's Constant = 1.38 x 10 -23 (Watt*sec/°Kelvin)į = Noise Factor (ratio), Noise Figure (dB) Increasing temperature affects receiver sensitivity by increasing input noise. Noise figure is a measure of how much noise a device (the receiver) contributes to a signal: the smaller the noise figure, the less noise the device contributes. A narrow bandwidth receiver will be more sensitive than a wider bandwidth receiver.
Minimum detectable signal (P min) depends on receiver bandwidth (B), noise figure (F), temperature (T), and required signal-to-noise ratio (S/N). The accuracy of the radar range equation is only as good as the input data. Minimum detectable signals are on the order of picowatts RCS for an automobile might be on the order of 100 square meters. Transmit power will be on the order of 1 mW (0 dBm) and antenna gain around 100 (20 dB) for an effective radiated power (ERP) of 100 mW (20 dBm). The variables in the above equation are constant and radar dependent except target RCS. The target is assumed to be in the center of the antenna beam. Below is one of the more basic forms for a single antenna system (same antenna for both transmit and receive).
-89cb7.jpg "radbeacon x4 range")
There exist hundreds of versions of the radar range equation.
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