System and method for managing ephemeris requests from client devices
A system and method for reducing peak loads on a network, includes: a server in communication with a plurality of GPS receivers, the receivers sending requests for an ephemeris to the server when a time of ephemeris (TOE) for a previous ephemeris expires; and the ephemeris received by the receivers being adjusted by the addition of a value to the TOE of the ephemeris, the value being randomly adjusted to a 16 second interval between 16 seconds and 30 minutes.
1. A method of reducing peak loads on a server transmitting ephemeris to a plurality of GPS receivers, comprising:
a) said server receiving a request for an ephemeris from a clients, said ephemeris having a time of ephemeris parameter;
b) adjusting said time of ephemeris (TOE) parameter by adding a value to said time of ephemeris; and
c) providing said adjusted ephemeris to a GPS receiver of said client.
2. The method of claim 1 wherein a Mean Anomaly at Reference Time (M 0 ) parameter of said ephemeris is adjusted relative to said value.
3. The method of claim 2 wherein an Inclination Angle at Reference Time (i 0 ) parameter of said ephemeris is adjusted relative to said value.
4. The method of claim 3 wherein a Longitude of Ascending Node of Orbit Plane at Weekly Epoch ((OMEGA) 0 ) parameter of said ephemeris is adjusted relative to said value.
5. The method of claim 4 wherein said TOE parameter, said M 0 parameter, said i 0 parameter and said (OMEGA) 0 parameter are adjusted at said server.
6. The method of claim 4 wherein said TOE parameter, said M 0 parameter, said i 0 parameter and said (OMEGA) 0 parameter are adjusted at said GPS receiver.
7. The method of claim 4 wherein said value is a 16 second multiple between 16 seconds and 30 minutes.
8. The method of claim 6 wherein said (OMEGA) 0 parameter is adjusted according to the formula:
(OMEGA) 0 =(OMEGA) 0+OMEGA DOT×dt
wherein dt equals said value and OMEGADOT represents a Rate of Right Ascension parameter of said ephemeris.
9. The method of claim 8 wherein said M 0 parameter of said ephemeris is adjusted according to the formula:
M
0
=
M
0
+
dt
×
(
GME
A
3
2
)
+
Δ
n
GME
=
3.986005
×
10
14
(
m
2
s
2
)
wherein A represents a semi-major axis parameter of said ephemeris, Δn represents a mean motion difference of computed value parameter of said ephemeris, m 3 is meters cubed and s 2 is seconds squared.
10. The method of claim 9 wherein said i 0 parameter of said ephemeris is adjusted according to the formula:
i 0 =i 0 +IDOT×dt
wherein IDOT represents a rate of inclination angle parameter of said ephemeris.
11. The method of claim 10 wherein said server receives a multiplicity of requests for ephemeris from said clients, and the determination of said value is randomized for each of said adjusted ephemeris provided to said receiver.
12. A system for reducing peak loads on a network, comprising:
a server of the network in communication with a plurality of GPS receivers, said GPS receivers sending requests for an ephemeris to said server when a time of ephemeris (TOE) for a previous ephemeris expires;
said ephemeris received by said receivers being adjusted by the addition of a value to said TOE of said ephemeris, said value being randomly adjusted to a 16 second interval between 16 seconds and 30 minutes.