Overview on Automatic Packet Reporting System – APRS
Bob Bruninga, a senior research engineer at the United States Naval Academy, implemented the earliest ancestor of APRS on an Apple II computer in 1982. This early version was used to map high frequency Navy position reports. The first use of APRS was in 1984, when Bruninga developed a more advanced version on a Commodore VIC-20 for reporting the position and status of horses in a 100-mile (160 km) endurance run. 
During the next two years, Bruninga continued to develop the system, which he now called the Connectionless Emergency Traffic System (CETS). Following a series of Federal Emergency Management Agency (FEMA) exercises using CETS, the system was ported to the IBM Personal Computer. During the early 1990s, CETS (then known as the Automatic Position Reporting System) continued to evolve into its current form. 
As GPS technology became more widely available, “Position” was replaced with “Packet” to better describe the more generic capabilities of the system and to emphasize its uses beyond mere position reporting. 
The Automatic Packet Reporting System was designed to support rapid, reliable exchange of information for local, tactical real-time information, events or nets. The concept, which dates back to the mid 1980’s, is that all relevant information is transmitted immediately to everyone in the net and every station captures that information for consistent and standard display to all participants. Information was refreshed redundantly but at a decaying rate so that old information was updated less frequently than new info. Since the primary objective is consistent exchange of information between everyone, APRS established standard formats not only for the transmission of POSITION, STATUS, MESSAGES, and QUERIES, it also establishes guidelines for display so that users of different systems will still see the same consistent information displayed in a consistent manner (independent of the particular display or maping system in use). See the original APRS.TXT. The two images below should give you an idea of the kinds of information available to the mobile operator on his APRS radio. On the left is the Kenwood D710 radio showing the station list, and on the right is the attached GPS with map display showing the location of other APRS stations. 
APRS is not a vehicle tracking system. It is a two-way tactical real-time digital communications system between all assets in a network sharing information about everything going on in the local area. On ham radio, this means if something is happening now, or there is information that could be valuable to you, then it should show up on your APRS radio in your mobile. See typical oversights and hear my talk on the 3 Oct 08 Rain Report See also some original APRSdos views and concepts overlooked in some new programs. 
APRS Internet System (APRS-IS): Like most other Ham radio systems, APRS has been fully integrated with the internet beginning with the efforts of Steve Dimse and the Sproul Brothers in 1997. Currently there are many web pages for live viewing of APRS activity such as APRS.FI, or FINDU.COM. 
APRS also supports global callsign-to-callsign messaging, bulletins, objects email and Voice because every local area is seen by the Internet System (APRS-IS)! APRS should enable local and global amateur radio operator contact at anytime-anywhere and using any device. See the APRS Messaging/Contact Initiative. 
APRS SPEC! . APRS continuously evolves. There have been several initiatives that have drastically improved APRS network performance and useability for users. The original APRS spec was updated in 2004 with the APRS1.1 addendum and since then with the APRS1.2 updates. 
Sample APRS VHF frequencies 
- 144.390 MHz — North America, Colombia, Chile, Indonesia, Malaysia, Thailand
- 144.575 MHz — New Zealand
- 144.640 MHz — Taiwan
- 144.660 MHz — Japan
- 144.800 MHz — South Africa, Europe, Russia
- 144.930 MHz — Argentina, Uruguay
- 145.175 MHz — Australia
- 145.570 MHz — Brazil
- 145.825 MHz — International Space Station
There is NO known assigned frequency for APRS by the NTC in the Philippines.
APRS in the Philippines
AFAIK, there is not too much APRS activity in the Philippines. Most of the stations are DMR and Echolink beacons through APRS-IS.
Here is an image capture from APRS.FI website.
RF-to-RF and RF-to-IS: There is an active APRS SatGate and Igate in District 6 by DU6DKL. Experimental APRS Stations are currently made, as of writing, in Cebu.
DV7HAA spearheaded the APRS System development in Cebu as his amateur project for 2020. Together with the DX7CBU-Ham Radio Cebu, Inc. members, slowly the APRS system in Cebu is making progress, with the specific motivation to aid Disaster Resiliency in Communications.
The project has a facebook group APRS-PH. As of the moment the APRS frequency is at 145.825MHz, same as to ARISS.
Automatic Packet Reporting System, Bob Bruninga, WB4APR , http://www.aprs.org/
Automatic Packet Reporting System, From Wikipedia, the free encyclopedia, https://en.wikipedia.org/wiki/Automatic_Packet_Reporting_System .